Q: Sharon Jane Culliford – When is the best time to plant out tulips and daffodils?
A: The ideal time for planting daffodils is as soon as they come on sale from late August onwards, and ideally should be in the ground by Christmas. However, daffodils are very forgiving bulbs, and I have planted them in the garden in late March – they flower the first year with no leaves, or a few very short ones, and the following year they don’t usually flower at all, but will recover to flower normally in the third or fourth spring after planting. Daffodils planted in pots can be planted out in the garden at any time.
Tulips should be planted later in the autumn, from late October onwards. Planting earlier is not usually a problem most years, but there can be a risk of frost damage to the developing flower bud if it is too far advanced and the ground freezes. Planting, again, should be completed before the turn of the year.
Q: Sandra Penny – Why do carnations change colour each year?
A: Spontaneous colour changing in flowers is known as ‘sporting’, and often occurs in highly-bred plants such as carnations, where many different species or varieties have gone into the make-up of a particular cultivar. It is caused by a change in character of one or more genes which can cause the plant to ‘throw back’ to a parent or other ancestor, may be unstable, in which case the colour would change annually, and therefore the plant would not be suitable to propagate from, or stable, forming a new variety if propagated from by cuttings, but not seed.
Q: Joanne Price – Any tips for growing carrots successfully? My children and I tried to grow some last year, but they ended up very small and puny! What did I do wrong?
A: Carrots need a well-drained but moist, deep, fine soil to grow well, which is why so many grown commercially come from sandy or peaty areas. Sow thinly and thin out regularly as the tops grow bigger. Thinning out can encourage carrot fly as handling the foliage causes a scent they can detect; to minimise this, thin on a cool, dull day, water the row thoroughly afterwards and clear up all thinnings – the larger ones can be used as ‘baby’ carrots. Carrot-willow aphis can also be a problem. The tops turn reddish and stunted and the roots fail to develop. To keep all pests at bay, grow under fine-mesh horticultural sheeting such as ‘Enviromesh’ except when cultivating and harvesting. In dry spells, especially when the plants are small, water regularly to encourage good root development without a check.
Q: Lauren Shanks – Do you have any tips for how I could try and keep my garden alive for a little longer? They [the plants??] seem to wilt and die very quickly…
A: The secret of happy, healthy plants is good soil, containing plenty of moisture-retaining organic material. Light soils need this annually, while heavy ones will become easier to dig and better for plant establishment with regular additions of farmyard manure, stable manure or well-made garden compost. Plants will last longer in deep soil; if it is not possible to achieve this (for example, if you have stony subsoil a few centimetres below the surface), try growing all your plants in raised beds. These can be a very attractive feature of a garden with brick, stone, or railway sleeper retaining walls. Make sure your plants never dry out, especially when newly planted, and add a slow-release fertiliser every year in spring.
Q: Supplementary question: Is it possible to prune my prunus ‘Amanogawa’ to make it less tall?
A: This spring-flowering tree, otherwise known as the flagpole cherry, is by no means a small garden tree; even though its natural habit is to grow upwards rather than outwards it can grow 5m or more tall in less than a decade, which means that in a very small garden it may become totally out of proportion. It can be pruned back, but taking the top out will spoil the attractive, slender form and it will regrow to be very bushy and un-shapely in a short time. You could try shortening back all the side branches, then cut back the lead shoot to retain the habit but, once pruned, it will need doing again regularly. You may find it better, therefore, to remove it completely and replace it with a slower-growing ornamental tree.