The problem with many gardening books and programmes is that they tend to assume that you understand all the terms associated with the subject, whereas in truth even the most experienced gardener sometimes has to check on definitions. You should find most words and expressions you are likely to encounter in the following glossary!
ACID, ACIDITY: Most substances are either acid, alkaline or neutral. Acidity is measured on the pH scale, the term pH referring to the percentage of hydrogen ions in the material. Things are neutral at pH7; numbers above 7 indicate that a substance is alkaline, figures below mean it is acid. The right quantity of an alkaline compound can neutralize an acid one, and vice versa. It is important to know if a soil, potting compost, or even water is acid, alkaline or neutral, as the pH value can affect the type of plant intended to be grown.
Some plants will only thrive in an acid soil and cannot tolerate the alkaline conditions found in the presence of lime. These are known as calcifuges and examples are heathers and rhododendrons. Other plants (e.g. cabbages) are calcicoles — that is, they prefer an alkaline soil — and there are plants which will do well in either. The pH of a soil can be checked by means of a chemical soil-testing kit or meter; if the soil is found to be unsuitable to grow a particular type of plant, substances can be added to it to adjust the pH.
AERATION: Introducing air between the particles of a soil by digging, forking, spiking, etc., to encourage healthy growth of the roots and allow beneficial bacteria to break down decaying materials into plant foods.
AEROBIC: See bacteria.
ALGAE: Primitive plants usually seen in the garden in the form of green slime on paths and clay pots, green water and blanket weed in ponds.
ALKALINE: See acid.
ALPINE: Technically a plant whose natural habitat is a mountainous region, but the term has become used to describe many more types of plant suitable for planting in a rockery. See also rock plants.
ANAEROBIC: See bacteria.
ANNUAL: A plant which completes the cycle of germination, maturing, flowering, seeding and finally dying in the period of one year. Many perennial plants, such as antirrhinums and fibrous-rooted begonias, are treated as annuals as they are at their best in their first year. Bedding geraniums now fit into this category as good plants of new varieties can be easily grown from seed using nothing more elaborate than the kitchen windowsill.
hardy annuals (HA) originate in temperate climates such as our own so they are not damaged by cold weather and can be sown direct into their flowering positions outside. They can therefore spend the whole of their lifespan in the open garden (e.g. Virginian stock, candytuft), half-hardy annuals (HHA) come from warmer climates than that of the United Kingdom. They are damaged or killed by frost and the seed needs a higher temperature for germination. They therefore have to be raised in a heated greenhouse or similar and kept there until all chance of frost has passed (e.g. lobelia, salvia).
ANTHER: The part of a flower producing pollen grains which in turn produce the male cells for fertilization; these fuse with the female cells, ultimately to develop into a seed.
AQUATIC PLANTS: Those growing in water.
BACTERIA: These are microscopic primitive organisms existing in their countless millions everywhere, soil contains vast numbers of them, mostly beneficial to plants. Aerobic bacteria require air to exist and break down decaying matter in the soil into soluble foods which can be taken up for healthy plant growth by the roots. Anaerobic bacteria can live without air, generally thrive in soggy sour soil and conditions of poor cultivation, and sometimes do more harm to plants than good. Other less desirable members of the bacterial fraternity can cause diseases in plants, but, in general, bacteria are some of a gardeners best friends.
BARE ROOT: Plants dug out of the ground during the dormant season (usually late autumn to early spring) to transplant them are known as bare root plants.Because the plants run a risk of their growth being checked by this method, many commercial growers now use containers, or offer plants with a protected rootball.
BARK: The outer protective layer of the mature stems of woody plants, usually brown, but sometimes other quite spectacular colours and often of interesting textures, for which two reasons alone many ornamental plants are grown. Bark from stripped timber is now being shredded or pulverized and compressed and sold for mulching purposes, or as a substitute for peat.
BED: Usually an island area of soil in a garden, for stocking with ornamental plants, or sometimes edible crops. It can be surrounded by lawn, paving, gravel, or other decorative surfacing and can be edged with a dwarf hedge, or with bricks, tiles, or similar.
BEDDING PLANTS: Those usually raised in seed trays under glass or in nursery beds and planted out in a mass for temporary display — this is known as abedding scheme. Bedding plants are usually planted out in the autumn for a spring display (e.g. wallflowers, forget-me-nots) or in late spring and early summer for the summer and early autumn period (e.g., French marigolds, stocks, petunias). A winter bedding scheme of hardy winter-flowering pansies has become very popular.
BERRY: Technically, this is a seed or seeds enclosed in a juicy pulp (e.g., tomato). Just to confuse the issue, the fruits we call berries (raspberries, blackberries and the like) are correctly known as drupes, but by regular usage the term ‘berry’ has become applied to many soft fruits that are botanically not berries at all.
BIENNIAL: A plant which in one year undergoes germination and develops leaves; flowers and seeds in its second year and then dies (e.g., foxgloves, carrots, cabbages). Many perennials are best treated as biennials (e.g., wallflowers and sweet williams). These are sown one year and encouraged to make sturdy unflowered plants that season, for replanting in bedding schemes to flower the following year, after which they are replaced. Left to their own devices they will continue to grow and flower every year but will gradually get more and more straggly and unmanageable, hence it is better to pull them up after their first year’s flowering and start again.
BLANCHING If a green plant is put into darkness by covering it with some light-excluding material or soil, it loses its green colour and turns white. This is often done to certain vegetables (e.g., leeks, chicory, celery) to make them sweeter and more tender.
BLEEDING: The leaking of sap from a wound when a plant is cut or damaged. It often occurs when pruning is done if a plant is not fully dormant and the sap is rising. It is not usually harmful, unless it is excessive; and can be stopped by applying cigarette ash to a small cut, or a sealing compound (or even oil-based paint) to a large one.
BLIND: A plant is said to be ‘blind’ when it stops growing at the growing tip. This usually occurs after an injury of some sort, ornamental plants will usually bush out from buds lower down the stem, vegetables should be scrapped. This term is also applied to flowering plants which fail to flower for some reason.
BLOOM: Another term for blossom, or flower. It can also refer to a waxy or powdery coating on some fruit (e.g., grapes and plums).
BLOSSOM: A flower or a collection of flowers.
BOLTING: This occurs when a vegetable produces its flower prematurely, and, in doing so, becomes unusable. It generally follows a check in growth, caused by something such as drought or root rot, and should not happen under conditions of good cultivation.
BORDER: An area of planted-up ground running around the edge of a feature such as a lawn or paving.
BOTTOM HEAT: The application of warmth to soil or potting compost from below, these days usually by means of soil-warming cables such as those incorporated into heated propagators. The warm soil encourages the germination of certain seeds, and the speeding up of the formation of the roots in cuttings.
BRANCH: Woody shoots of a tree or shrub not forming a single trunk in the case of a shrub, and usually growing from the upper part of the trunk in the case of a tree.
BRASSICA: A member of the cabbage family (e.g., Brussels sprout, cauliflower, wallflower stock).
BREAK: The formation of Side-shoots in a plant. Also a bud at the moment of its opening is said to be breaking.
BROADCASTING: Scattering seed all over an area (for example, when seeding a lawn), instead of sowing in straight lines.
BROAD-LEAVED: A term used to describe plants with broad, flattish leaves, instead of spike or sword-like ones (e.g., grasses) or needles (like some conifers).
BUD: The part of a plant containing embryo leaves, flowers and/or stems.
BUDDING: The implanting of a growth bud in the bark or outer layer of stem of another plant. The resultant plant will have the characteristic flowers and leaves of the plant from which the bud was removed, but the growth habit or vigour of the rootstock. This is still the most widely used method of propagating roses.
BULB: This is strictly speaking a swollen, modified leaf base which acts as a food storage organ for the plant during its dormant period (e.g., daffodil). Like the term berry, the definition of the word bulb has been widened to refer to any fleshy modified stems such as those produced by gladioli and crocuses (which are really corms), and roots, like those of the dahlia and some begonias (which are actually tubers).
BUSH: A woody plant with a group of stems, as opposed to a tree, which usually has only one stem, or trunk. In gardening terms, the word bush is generally used in connection with roses and fruit, the word shrub being applied to the remainder.
BUSH FRUITS: These are produced on low bushes (e.g., currants).
CALCICOLE: A plant that thrives on an alkaline soil. See also acid and lime.
CALCIFUGE: A plant that needs an acid soil.
CALYX: A whorl of modified leaves forming the outer case of bud or envelope of flower.
CANE: A thin stake, usually made of bamboo, used to steady or train plants. Also a long, cane-like stem produced by certain plants (e.g., blackberry).
CANE FRUITS: Types of fruit bushes producing cane-like stems (e.g., blackberry, raspberry).
CHITTING: The practice of letting certain plants (e.g., potatoes) sprout before being planted.
CHLOROPHYLL: The green pigment in most plants which combines water (in sap) and carbon dioxide from the air in the presence of sunlight to produce sugars to feed the plant, during which process oxygen is given off as a waste product. If a plant loses its natural green colour and begins to turn yellow, it is said to bechlorotic. This condition is often caused by a lack of available iron and magnesium in the soil, and frequently happens with calcifuges, as these minerals are ‘locked up’ in a soil with a high pH in a form which the plants cannot absorb.
CLAY: A soil made up of minute particles of mineral rock.
CLOCHE: A portable structure of glass or other transparent material (e.g., PVC, polythene), used to protect early crops against bad weather and to encourage earlier maturing.
COCOA SHELL: The outer husk of the chocolate bean, which makes an excellent mulch.
COIR: The outer covering of the coconut. Originally used as matting, it is now composted as a substitute for peat, or woven into hanging basket liners.
COLD FRAME: See frame.
COMPOST: This word has two totally different meanings which are often confused. It can refer to garden or kitchen refuse which has been rotted down in a heapor bin and is dug in as a useful soil improver. It can also mean a mixture based on peat or peat substitute sometimes containing good quality loam) into which seeds are sown, cuttings struck (.see strike) and plants potted (see potting).
CONIFER:A type of evergreen, which usually (though not always) produces its seed in structures called cones. They generally have specially-shaped leaves, often needle-like.
CONTAINER: A receptacle in which a plant or plants are grown independent of the open ground. A container can be almost anything from an antique stone urn to an old bucket. In recent years ‘containerization’ has become a popular way of growing nursery stock for replanting and resale. By this method, until they are ready for planting in their permanent positions, plants are grown from the seed or cutting stage in a series of containers of increasing size, potting on into larger ones as they grow bigger, instead of being raised in the open ground and dug up for replanting. In this way, when the plants are eventually ready to plant out, they suffer the minimum of disturbance and consequently re-establish themselves more quickly.
CORDON: A method of training a plant, usually a fruit bush or tree. Instead of allowing it to branch naturally, growth is usually restricted to one, though sometimes to two or three stems supported by canes and/or wires. The main purpose is to enable more than one variety to be grown in a small space.
CORM: A swollen modified stem base with a similar function to that of a bulb (e.g., crocus).
CROWN: The top part of the roots, from which shoots emerge. Also the mass of branches at the top of the trunk of a tree.
CULTIVAR: See variety.
CULTIVATION: Working land or soil for the purpose of growing plants on it; also giving active attention to the growth of plants or crops.
CUTTING: A piece of a plant removed from the parent and prepared in some way, which will eventually grow roots and shoots of its own and develop into a new independent plant.
DEAD-HEADING: The practice of removing dead flower heads. This serves two purposes — to tidy up the plant and to encourage the production of further flowers.
DECIDUOUS: Plants that lose all their leaves once a year, usually in winter.
DISEASE: A plant illness not directly caused by pests. Usual causes of disease amongst plants are fungi, bacteria and viruses.
DISORDER: A plant malfunction not caused by pests or disease. Unsuitable growing conditions, bad cultivation and soil deficiencies are all responsible for plant disorders.
DIVIDE: To split a plant into several sections, each having its own portion of roots, for propagation purposes.
DORMANT: When a plant is in a state of rest. In plants, growth and other functions are much reduced and in a deciduous plant the leaves fall off. Dormancy usually occurs in winter and is the best time to transplant as a plant is less likely to sustain a shock to the system while at its least active.
DRESSING: A substance supplying plant foods applied dry to a soil. Top dressings are added to the surface, base dressings are incorporated into the soil when digging.
DRILL: A channel made in soil into which seeds are sown, and then covered up. Also an appliance for sowing seeds.
DUST: A pest or disease control applied to a plant or the soil as a fine, dry dust as opposed to a liquid spray.
DWARF: A plant of naturally small and slow-growing habit.
ERICACEOUS PLANTS: Plants belonging to the heather family, including rhododendrons, which are calcifuges and therefore require special growing conditions in an acid soil, preferably one containing some peat.
ESPALIER: A method of training plants, mainly apples and pears, which are then themselves known as ‘espaliers’ where the branches are trained out horizontally at approximately 15-inch (400 mm) intervals, usually along wires for support. Espalier-trained trees are ideal for planting against walls, as the warmth from the wall helps make the fruit, and also the wood, ripe, so making the wood more frost resistant. Espaliers also make a useful division or screen between different parts of a garden.
EVERGREEN: Plants which do not shed all their leaves at once at a certain time of the year. They do lose leaves, but gradually, a few, usually the oldest, at a time — so the plant never becomes totally bare as deciduous plants do. EYE A growth bud, usually dormant, from which new growth is capable of arising.
F1 HYBRIDS: The first generation from a cross between two plants. This expression has come to refer to plants raised in this way by plant breeders from specially selected parents. seed so obtained is usually expensive because of the amount of effort which has gone into its production, but the resultant plants are very strong and healthy (this is known as hybrid vigour), with special characteristics purposely bred into them. Seed from F1 hybrids will not breed true to the parent plants; the resulting seedlings are known as F2 hybrids and usually turn out to be a pretty motley crew, though not, in many cases, without their own merits.
FAMILY: A group of several genera (see genus) of plants. For example the rose family (Rosaceae) contains many smaller groups (genera) such as malus (apples),pyracantha (firethorn) and cotoneaster, all with basically similar characteristics.
FAMILY TREE: One where more than one variety has been grafted on to one rootstock. This is often done with apples and pears, to enable several sorts to be grown on one tree when space is limited.
FAN: A method of shaping certain plants, often plums, peaches and figs, in which branches are trained into a flat fan-shape and supported by a fence, wall or similar means.
FARMYARD MANURE: Animal excreta and straw or other bedding materials, partially rotted down, which is a rich source of humus and plant foods when incorporated into soil.
FASTIGIATE: A tree with an erect growth habit, such as the Lombardy poplar.
FEATHERED: You will sometimes encounter this expression in nursery catalogues. It means a young tree with branches growing right down the stem, instead of having a clear trunk.
FERN: A rather primitive group of green plants which do not flower, and reproduce themselves by spores instead of seeds.
FERTILE: A plant is fertile if it is capable of producing seed, soil is fertile if it is of good texture, rich in humus, beneficial organisms and plant nutrients, and thus able to support strong, healthy plants.
FERTILIZATION: The fusion of a male and female cell. In the case of plants, this happy event ultimately produces a seed.
FERTILIZER: A compound providing plant foods, usually in a concentrated form.
FILAMENT: The part of the male organ of a flower supporting the anther.
FLESHY-ROOTED: Plants with thick, fleshy roots.
FLOWER: The sex organs of a plant, usually surrounded by a protective ring of often eye-catching petals and sepals which attract creatures for pollination, so that a seed or seeds can be formed.
FOLIAGE: The leaves of a plant.
FRAME (COLD FRAME): A protective structure, made of glass or other transparent material, similar to, but generally lower and smaller than, a greenhouse. It can be used in a similar way to a cloche, and also for hardening off young plants raised in heat to prepare them for planting out. Frames are usually placed horizontally, although narrow, vertical frames are also available for attaching to a wall.
FROST: This arises when the temperature falls below 32°F (0°C) and can be damaging to tender plants not suited to low temperatures, unless protection is given in some way.
FRUIT: Any seed-bearing organ: a pod, a berry and a nut are all technically ‘fruit’.
FUNGICIDE: A chemical formulated specifically for controlling fungus diseases on plants.
FUNGUS: A type of plant which contains no chlorophyll and therefore, unlike green plants, cannot make its own food. A fungus derives sustenance from other living things, when it is known as a parasite, or dead ones, when it is a saprophyte. Saprophytic fungi can be very beneficial in that they help to break down dead matter into food for other plants as well as themselves, but some parasitic ones cause disease on plants, and have to be controlled with fungicides.
GARDEN: To tend or cultivate an area of ground; the piece of ground receiving this attention.
GARDEN CENTRE: A retail outlet for plants, sundries and other gardening accessories.
GENUS (plural genera): A group of plants all very similar in characteristics to each other, e.g., members of the genus sorbus (mountain ash and whitebeam) are all recognizably alike in many details. The generic name (in this case sorbus) is like a person’s surname, the specific name (see species) being akin to a first name.
GERMINATION: The stage at which a seed begins to grow roots and shoots to become a plant.
GLASS: In gardening parlance, a collective term referring to all structures made entirely or partly of glass or other light-transmitting material and designed for the protection of plants.
GRAFT: A process in which one plant is artificially combined with another. The main reason for doing this is to ‘borrow’ some of the characteristics from the rootstock (the part receiving the graft) for the scion (the piece being grafted on). For example, an apple tree may grow far too large on its own roots. If a piece of it is grafted on to a ‘dwarfing rootstock’ it will inherit the slower growth habit of the stock, while retaining its own fruiting characteristics.
GRASS: Plants which are members of the Graminaceae family, having strap-, spike-or sword-like leaves and usually feathery flower-heads. Grass is also the term used to describe thin, grass-like leaves produced by young bulbs and sometimes bulbs suffering from certain disorders.
GREENHOUSE: A structure of glass or other transparent material on a wooden or metal framework for the cultivation and protection of plants, mainly ones which through some or all of their lives could not survive out of doors in a particular environment. Greenhouses are generally used to protect plants from low temperatures, but can also be used to protect them from excessive moisture. An example of this is the alpine house, which is not heated, but is used to house collections of alpines, plants whose normal habitat is crisp, dry localities and that take exception to our cold, damp winters if permanently planted outside.
GREEN VEGETABLES: Ones grown primarily for their leaves, e.g., cabbage, spinach, etc.
GROUND COVER PLANTS: Ones suitable for close planting which will eventually cover the ground completely and so exclude weeds.
GROWING BAG: A long, flattish, heavy-duty plastic sack filled with potting compost which is used as a temporary container in which to grow plants, especially vegetables.
GROWING TIP: The tip of a shoot, from which growth is made.
HALF-HARDY: Plants that in our climate will live outside only in summer, and are killed by frost.
HARDENING: OFF Gradually accustoming plants raised in warmth to cooler conditions. See frame.
HARDY: A plant that should be capable of thriving outside all the year round.
HAULM: The stem of a plant, usually applied to vegetables, e.g., pea, bean, potato.
HEAD: A cluster of flowers, collection of branches at the top of the trunk of a tree, or the hearted part of a green vegetable, e.g., cabbage.
HEDGE: Shrubby plants grown in a continuous row as a boundary or division.
HEEL: A small side-shoot torn from the parent plant with a piece of bark attached at the base, often used as a cutting.
HEELING IN: The practice of planting bare root stock temporarily if the permanent site is not ready, in order to prevent the roots from drying out.
HERB: This word is now generally taken to mean plants, often aromatic, grown for seasoning food, medicinal purposes, or for the fragrance of their leaves or seeds.
HERBACEOUS: Herbaceous plants are those with soft, not permanently woody, upper growth. An herbaceous border contains a collection of such plants.
HERBICIDE: A chemical which will kill plants, often referred to also as a weedkiller.
HOUSE PLANTS: Are usually of a tender nature and have been grown for indoor decoration.
HUMIDITY: Moisture in the atmosphere.
HUMUS: Organic matter in soil.
HYBRID: A cross between two species of plant. Hybridization is the deliberate crossing of parent plants, and is usually performed by plant breeders to produce a new variety.
INORGANIC: This word really refers to the fact that a substance does not contain carbon. Over the years it has come to refer to a method of cultivation where inorganic fertilizers (‘artificials’) are used as a supplement to (or instead of) organic ones (the organic in this context intended to mean those derived from natural sources) and chemicals having a synthetic method of manufacture, instead of those of natural origin, are used to control pests and diseases. Exponents of ‘organic growing’ methods contend that ‘inorganics’ are unnatural or harmful in some way. However, plant foods in such substances are often obtained from minerals occurring naturally, and many organic compounds (that is, those containing carbon) can be produced synthetically. Most synthetic insecticides and fungicides contain carbon, and can be anything but harmless if used incorrectly, although technically ‘organic’. At best, many so-called ‘natural’ organic fertilizers are produced from slurry or poultry manure from intensively farmed animals, so the concept of ‘natural’ and ‘unnatural’ can become somewhat confused.
INSECTICIDE: A chemical that will kill insects and often other small garden pests such as mites as well, though the latter is more correctly known as an acaricide.
INTERNODE: A piece of stem between two leaf joints.
Sorry… nothing to learn here!
Sorry… nothing to learn here!
LATERAL: The term used to describe side growths on the main stems of a tree or shrub.
LAWN: A specially cultivated piece of grassland, for ornamental or recreational purposes.
LAYERING: Pegging down a young branch or stem into the soil, so that the point which touches the soil produces roots and will eventually form a new plant. This occurs naturally sometimes if a stem touches the ground somewhere along its length.
LEAF-MOULD: The dark brown, broken-down remains of leaves, very good as a soiL-improving material. True leaf-mould differs from compost in that the latter is mainly broken down by bacteria, whereas in leaf-mould the materials are broken down by the action of fungi.
LEAVES: The part of a green plant containing most chlorophyll and therefore the main food-manufacturing part.
LEGUME: A member of the pea and bean family.
LIFT: To dig up a plant from the ground.
LIME: A blanket term used by gardeners to cover several compounds containing calcium which can be added to soil to improve the texture, sweeten it, and increase its alkalinity (see acid).
LOAM: Another word for soil, especially that of good quality.
MAIDEN: A young tree or bush in its first year, after grafting or budding before any pruning or training has taken place to begin the formation of its eventual shape.
MANURE: A substance, often bulky, containing and capable of supplying organic plant foods when added to soil. Green manure is a quick-growing leaf crop, capable of decaying to produce plant foods, which is dug in on maturity to rot down, e.g., mustard.
MARKET GARDEN: An enterprise, usually commercial, for the raising of mainly food-producing plants (fruit and vegetables).
MICROCLIMATE: An environment in a limited area differing in some respect from that surrounding it. It can refer to an area outside, such as one sheltered by trees and shrubs, or to the inside of a greenhouse, or even to the practice of surrounding the pot of a house plant with an outer container of moist absorbent material to raise the humidity in the immediate vicinity through evaporation.
MICROPROPAGATION: A method of propagation in which tiny pieces of plants are reproduced rapidly in a series of nutrient solutions. This produces vast quantities of propagation material and consequently new plants, very fast. As yet the method is mainly used by professional nurserymen because laboratory conditions are essential.
MISTING: Spraying the leaves of plants with a fine mist of water to prevent them from becoming dehydrated in hot, dry conditions.
MULCHING: The application of a thick layer of a substance to the surface of the soil. Mulches are usually of bulky, naturally occurring materials such as bark, coir, compost, cocoa shell, farmyard manure, shredded garden waste, grass clippings, etc. The main function is to retain moisture in the soil by preventing excessive evaporation, but mulches have the additional benefit of adding plant foods to the soil and keeping roots cooler in hot weather. A well-applied mulch will also smother weeds. Black polythene is sometimes used as a mulch, though mainly in vegetable gardens as amongst ornamental plants it tends to look rather untidy. Woven fibre mulches, which are laid as a sheet and allow rainwater to permeate, are becoming more popular.
NATURALIZING: A form of gardening where plants are positioned informally and left more or less to ‘do their own thing’. Daffodils are suitable for this kind of semi-wild cultivation.
NEMATODE: A tiny organism often living off animals or plants. Nematodes can be beneficial or harmful to plants according to their way of life.
NEUTRAL: See acid.
NODE: Positions on a stem where leaves or leafbuds are capable of appearing.
NURSERY: A place where young plants, known as nursery stock, are raised. Nursery beds are beds in which young plants are grown and tended until well-developed enough to be transferred to their permanent positions.
NUT: A seed with an outer shell, usually hard, and an inner skin.
OPEN GROUND: Ground for cultivation not protected by a covered structure.
ORGANIC: Literally, an organic compound is one containing carbon. Many organic compounds are produced from the breaking down of plant or animal remains, especially substances in rotting manure, compost and the like which in turn become plant foods. See inorganic.
ORNAMENTAL: A plant grown mainly for decorative effect.
OVARY: The part of the female organ of the flower containing the ovules.
OVULES: Female cells contained in the ovary of a flower.
PANNING: An undesirable condition of the surface of a soil, usually a heavy one, which has become smooth and hard. The problem is usually caused either by too much walking on a particular area, or by breaking the soil down too finely during cultivation. Heavy rain then settles down the surface into a crust, which eventually dries out to a rock-hard finish. The germination of seed is difficult under such conditions and young plants cannot thrive. A pan should be broken up by thorough digging and steps taken to improve the soil’s texture by adding humus-forming materials to prevent it happening again.
PARASITE: A plant or animal obtaining nourishment directly from the body structure of another living organism.
PEAT: Like compost, peat is formed from vegetable remains, but occurs in wet, acid places where aerobic bacteria have not been able to rot it down properly. It is used for horticultural purposes mainly as an ingredient of soil-less composts.
PEAT SUBSTITUTES: Substances derived from non-peat sources (coir, wood waste, etc.) used in compost, mulches or for soil conditioning.
PERENNIAL: Strictly speaking, this means any plant with a life cycle longer than two years (often indefinite). The expression has come to refer mainly to herbaceous perennials, although trees, shrubs, bulbs, and many other types of plant should correctly be placed in this category.
PERLITE: Expanded volcanic rock in granules used as an additive to soils and composts to improve the texture, retain water and let in air. It is very lightweight and therefore easier to handle — both on its own, and in combination with peat or peat substitutes for soil-less composts — than sand.
PERPETUAL flowering: A plant with a prolonged or indefinite flowering period, as opposed to one which only has a single flush.
PEST: A living creature which can cause damage to plants. PESTICIDE A chemical for killing or controlling pests.
PETALS: The parts of a flower, often eye-catching, surrounding the male and/or female reproductive organs.
PHOTOSYNTHESIS: The process in which the chlorophyll in plants combines water in sap and carbon dioxide from the air in the presence of sunlight to make sugar from which are created many more complex food compounds for the support of the plant during its lifetime.
PINCH: To remove the growing shoot of a plant in order to make it bush out. (See stopping.)
PISTIL: The female organ of a flower. PLANT FOODS Chemicals in solution in soil, capable of being absorbed by a plant for feeding purposes. Plants also make certain energy-giving foods by photosynthesis.
PLANTLETS: Baby plants produced by certain species as a means of vegetative propagation.
PLANT OUT: To place a seedling or other young plant in its permanent position after its time in a seed tray or nursery bed.
PLUNGE: To submerge a pot-grown plant up to its rim in soil outside or in a specially made ‘plunge bed’. Many house plants may be treated like this during the warmer summer months and pots of bulbs required for indoor decoration can be plunged several inches deep after planting to encourage the production of strong, healthy roots before the top growth develops.
POD: A dry seed container capable of splitting into two halves down its length and enclosing many seeds, e.g. peapod.
POLLEN: Dust-like grains producing male reproductive cells found in the anthers of most flowering plants. Pollination occurs when these male grains alight on the female stigma after which fertilization takes place if the male and female cells (known as gametes) successfully fuse. Pollination is brought about naturally by wind, animals, insects or in self-pollination by the pollen falling on to the stigma in the same flower and can be done artificially by dusting the appropriate parts with a soft paintbrush or similar.
POT: A receptacle usually, but not always, having drainage holes in the bottom, and intended for containing a growing plant.
POT-BOUND: A state reached by a plant when its roots have entirely filled its container. Some plants flower better in this condition, as they are placed under stress, but generally speaking a pot-bound plant will start to deteriorate if its roots are restricted too much, and it should be replanted in a bigger pot.
POT-GROWN: A plant grown in a container. The term is often used to describe the method of raising new stock in a series of containers until it is finally planted in its permanent site in the open ground.
POTTING: The transference of a plant from a seed tray into an individual pot, or the replanting from a small pot into a bigger one. (Also known as ‘potting on’.)
PRICKING OUT: The planting out of seedlings from the container in which they reached germination into another container or bed where they can be spaced further apart to allow more room for development.
PROPAGATION: Increasing a stock of plants. Naturally, this occurs through seed production, and also by producing plantlets, runners, stolons, or similar. In addition to these methods gardeners can increase their stock through cuttings, layering and the like, and also by the comparatively new method of tissue culture. A propagator or propagating case is a container with a transparent lid fitting over a tray base which may contain or be attached to some form of heating appliance, and is filled with compost or other growing medium. The purpose is to create a beneficial microclimate with increased warmth and humidity for the germination of seeds, and to raise seedlings and strike cuttings.
PRUNING: The cutting back of woody plants to encourage the formation of a healthy, well shaped specimen and improve or control flower production.
Sorry… nothing to learn here!
RESPIRATION: In this process, plants absorb oxygen from the air to turn the sugars formed during photosynthesis into energy for growth, carbon dioxide being given off as a waste product.
RHIZOME: This is an underground stem, producing roots along its length and one or more shoots at the end. Many are fleshy and are used as food storage organs for the dormant period (e.g., bearded irises) but some, like those of couch grass, are long and thin.
RIPE: A state of maturity, in fruits, usually encouraged by warmth, sunlight and chemicals in the soil. Young growths on trees and shrubs are ripe when they turn woody.
ROCKERY, ROCK GARDEN: An area where alpine and rock plants are grown, and which usually, but not necessarily, contains rocks or large stones arranged as if in a natural outcrop.
ROCK PLANTS: Technically, a rock plant is not the same as an alpine, which should come from a mountainous region to qualify as such, but in practice the terms have come to be accepted as the same, i.e. dwarf, slow and low-growing plants which are suitable for growing on a rockery. ROOTBALL (BALL) This is the term used to describe a mass of soil and roots either occurring naturally with some plants having fine fibrous roots, or more often it is what is found when a pot-grown plant is removed from its container. Generally speaking, when replanting or repotting this ball must not be damaged, and whenever possible it should be kept intact.
Sometimes plants are offered for sale with a ball of soil around their roots kept in place with sacking or netting. This prevents the roots from drying out before they are replanted and the plant usually stands a higher chance of survival.
ROOTS : The parts of a plant which anchor it to the soil or growing medium, and absorb moisture and plant foods in solution through root hairs at the tips.
ROOTSTOCK, STOCK: A plant into which a graft is inserted, or which provides the roots when budding is done.
ROOT VEGETABLES: Those grown primarily for their edible roots such as carrots, parsnips, etc. In some cases other parts can also be eaten (e.g., the tops of turnips).
ROTATION: A method of growing crops so that no two similar ones are grown in succession in the same plot. This is done mainly to prevent the build-up of pests and diseases affecting a certain crop and also so that manure and fertilizer can be applied to best possible effect and any special benefits of certain groups of plants (e.g. peas and beans) can be maximized. (See pages 284-5 for a suggested 3-year rotation for the vegetable garden.)
RUNNER: A stem running along the surface of the soil which produces new plantlets at intervals from the nodes. This is a good method of propagation in certain cases, e.g., strawberries.
SALAD VEGETABLES: Those intended to be eaten raw in salads, e.g., lettuces, radishes and spring onions.
SAND: A substance consisting of small particles of broken mineral rock.
SAP: The liquid in plants (rather like plant’s blood) containing water, plant foods and substances such as hormones, which control the plant’s growth and development.
SAPROPHYTE: A plant or animal living directly on dead and decaying matter for feeding purposes, such as some fungi.
SCION: The part joined on to the rootstock when a graft is made.
SEED: A structure designed for sexual reproduction. A seed is formed when a male cell in pollen combines with a female ovule. A seed is really an embryo plant capsule with enough stored food for nourishment during germination until the resultant seedling is capable of absorbing food itself through its roots.
SEED BED: A finely cultivated area of ground into which seed may be sown.
SEED COMPOST: A fine grade of compost suitable for sowing seed into.
SEED DRESSING: A coating of chemicals designed to control any pest or disease which might affect the seed or the resultant young seedlings.
SEEDLING: A baby plant grown from a seed.
SEED TRAY: A flattish receptacle in which seed can be sown in compost, sometimes referred to as a seed pan.
SEPALS: The leaf-like outermost parts of a flower, collectively known as the calyx.
SET: Specially selected or treated parts of a plant, capable of being grown on into a crop, e.g., onion sets. A flower which is beginning to develop fruit or seed after fertilization is also said to have ‘set’.
SHADING: Providing means of partially obscuring sunlight, often under glass.
SHOOTS: New vertical growths in plants.
SILT: A soil comprised of very tiny particles of broken mineral rock.
SOIL: The upper layer of earth which supports higher plant life. This consists of disintegrated rock, organic matter and beneficial organisms including bacteria.
SOUR SOIL: An acid soil in which the balance between plant remains and organisms has become out of order. SOW To scatter or otherwise introduce seed into the earth or purpose-made compost in order to raise plants.
SPECIES: A group of plants resembling each other in all but minor details and which can interbreed easily and successfully.
SPECIMEN: A plant specially selected for individual display.
SPHAGNUM: A type of coarse moss which when it decays in a certain way under wet conditions forms sphagnum moss peat.
SPIKING: To introduce air into compacted soil with a sharp, spiked tool such as a fork or other gadget with spikes on it.
SPIT: The depth of a standard spade or fork in soil.
SPRAY: Several flowers grouped on a single stem. This word is also used to denote the spreading of fine droplets of a liquid over the surface of a plant by means of a device known as a sprayer.
SPROUT: A new shoot, or the production of this shoot.
SPUR: A cluster of buds on a fruit tree which will open to form flowers.
STAKE: A straight support introduced at the side of a plant to keep it straight and prevent it from falling or blowing over.
STALK: A stem-like growth supporting leaves or flowers.
STAMENS: The male organs of a flower.
STANDARD PLANT: One trained to grow on a single stem for a certain height, and then pruned to form a head of stems or branches.
STEM: The part of a plant which has buds from which can grow flowers, side-shoots or leaves.
STIGMA: The part of the female organ of a flower that collects the pollen.
STOCK: See rootstock.
STOCK PLANT: One kept to provide material for the propagation of new plants.
STOLON: A stem that can produce new roots and shoots at its tip, as, e.g., the blackberry does.
STOMATES: The pores through which a plant breathes, usually found on leaves, mainly on the underside, but occasionally on the stem as well.
STONE FRUITS: Those like plums, which contain a hard stone (the technical term for these fruits is drupe).
STOOL: The term for both the crown of plants (e.g., chrysanthemum) lifted annually and used for propagation, and for shrubs or trees pruned down to ground level every year and so kept as a cluster of young stems. In the latter case, stooling is done either to provide young stems for propagation, or because the young stems (and perhaps their leaves) are the decorative feature for which the plant is grown.
STOPPING: The removal of a growing tip to encourage the production of Side-shoots.
STRIKE: To take a cutting of a plant, which is said to have struck when it has started to produce roots.
STYLE: The part of the female organ of a flower which conducts the male cells in pollen to the ovary.
SUBSOIL: The infertile layer of soil below the topsoil, lacking in humus and plant nutrients.
SUCKER: A shoot arising from the rootstock of a budded or grafted plant, which must be removed to preserve the desired habit. A sucker is also a secondary growth developing from an underground bud, by which many plants produce natural thickets.
SYSTEMIC: A substance capable of being absorbed into a plant’s tissue.
TAP ROOT: A strong, straight root growing downwards into the soil.
TENDER: Plants which cannot grow outside permanently in a climate likely to experience frost.
TENDRIL: The twining part of certain climbing plants, by which they can support themselves.
THERMOMETER: A gauge for measuring temperature.
THINNING OUT: The removal of certain overcrowded plants, shoots, or stems to enable better development of the remainder.
TILTH: A soil in cultivation, broken down to a fine texture, and suitable to sow seed in.
TOLERANT: Plants which will tolerate certain substances or conditions without adverse effect.
TOP FRUIT: fruit which is produced on a tree or treelike bush, as opposed to bush fruit (e.g., blackcurrants) which are produced on low bushes.
TOPSOIL: The top layer of a soil which is usually fertile and capable of supporting healthy plant life.
TRAINING: By manipulating, pruning or general cultivation a plant is ‘trained’; i.e. persuaded to grow in a specific form, e.g., espalier.
TRANSPIRATION: The giving-off of water through the stomates as a part of the process of photosynthesis.
TRANSPLANT: To move a plant from one location to another.
TREAD: To firm down soil gently with the feet.
TREE: A woody plant growing on one main stem or trunk, and of fairly mature age, as opposed to a shrub or bush, with many stems.
TRUNK: A hard, woody, main stem of a tree.
TUBER: A swollen stem or root used by certain plants for food storage in the dormant period. Potatoes are stem tubers, dahlias are tuberous roots.
TURF: A piece of grass, roots and soil cut from mature grassland for re-establishing elsewhere usually as a lawn. The expression turf is also used to denote the actual grassland itself.
UNION: The point at which a scion is combined with a rootstock.
VARIEGATED: Plants whose leaves and sometimes stems have two or more colours; e.g., some hollies have green and cream or gold leaves, and these are described as variegated. Variegation is often caused by lack of chlorophyll in certain parts of the leaf or by a virus and so a variegated plant can often be weaker in growth than the plant from which it originated.
VARIETY: A group of plants in a species similar to each other but different from other groups in the species in some respects, e.g., Chamaecyparis lawsoniana‘Allumii’ is a variety of Chamaecyparis lawsoniana, the Lawson’s cypress. Varieties which have occurred in cultivation either by deliberate breeding or by accident are called cultivars (short for cultivated variety).
VEGETABLE: In common usage, a vegetable is a plant grown primarily for the edible qualities of one or more of its parts.
VEGETATIVE PROPAGATION: To increase the stock of a plant by any method other than by growing from seed.
VENTILATION: To provide fresh air in an enclosed structure (e.g., a greenhouse).
VERMICULITE: A lightweight substance formed by heating certain minerals such as mica. It can be added to peat, or peat substitute, to form a potting compost, or used on its own to provide a soil-less growing medium.
VIRUS: A minute organism about which comparatively little is known at present, capable of producing disease and disorder in any plant or animal it invades.
WALL PLANTS: Those suitable for growing up or training on walls.
WATER: A naturally occurring compound of hydrogen and oxygen, and liquid at normal temperatures, water is essential for the life of a plant. Watering is the artificial application of water to plants by one means or another.
WEEDKILLER: A herbicide used for the killing or control of weeds.
WEED: ‘Something growing where it is not wanted!’ Weeds are the most successful of plants, being vigorous, invasive and persistent.
WHIP: A young tree with a single thin stem or trunk.
WILT: A term used to describe the turning limp and subsequent collapse of a plant, which can be due to lack of water, injury, or disease.
WINDBREAK: A living or constructed shelter to prevent the full force of a wind from damaging plants growing behind it. It should not be a solid structure, which encourages harmful draughts, but should filter the wind as does a hedge.
WINDFALL: A fruit which has fallen off the tree on to the ground; it should be eaten immediately as it will quickly start to rot.
WINDROCK: An effect of wind on plants which causes damage to roots. It can result in death unless a windbreak is constructed, or a cane or stake supplied.
WORKED: A budding or grafting term. The expression ‘top-’ or ‘bottom-worked’ is often encountered in connection with a grafted tree. This refers to whether the scion has been introduced at the top or bottom of the trunk.
Sorry… nothing to learn here!
Sorry… nothing to learn here!
Sorry… nothing to learn here!