These are the plants usually seen for sale in trays and boxes in nurseries, garden centres and outside the corner shop at the beginning of summer. As already mentioned, there are many half-hardy perennials which, if treated as half-hardy annuals, make good, compact plants the first season with plenty of flowers, and are inexpensive and easy enough to produce and to discard at the end of the summer and raise new ones each year. What they all have in common is the fact that they are not tough enough to tolerate the frosts and low temperatures of winter.
- As mass bedding plants for colour during the summer months.
- In tubs, boxes, hanging baskets, etc.
- To add colour at the front of shrubberies and fill in spaces in all types of ornamental beds and borders.
- As a temporary fill-in prior to permanent planting later.
- They provide instant colour – they are usually either in bud or in flower when planted out.
- They require very little maintenance once established in their permanent positions – many modern varieties do not even require dead-heading.
- They come in a wide range of types suitable for most positions – one or two will even put up with some shade, if it is not too heavy.
- If you raise them yourself from seed you need to give them some warmth until the time approaches for planting out. This means that the seed has to be germinated in a heated propagator in a cold greenhouse, or in a warm greenhouse with a temperature of about 65°-70°F (18-21°C), which is expensive. Alternatively, they can be raised on a windowsill in a light room but they take up a lot of space ultimately and tend to become drawn and ‘leggy’ because they lack the overhead daylight of a greenhouse.
- If you do not raise them from seed they are expensive to buy.
- They need quite a bit of attention — watering, weeding, etc. once they are planted out until they become rooted into the soil and start to grow and spread outwards.
Obtainable as seed from usual sources (the choice of varieties is wider if purchased by mail order from seed merchants), or as plantlets to grow on, also from seed companies. Ready sown and ready-to-sow starter packs are available for ease of raising though these are expensive compared with packeted seed. Plants ready for planting out can be bought from nurseries, garden shops, etc.