Annuals can be divided into two groups, hardy and half-hardy. Here we talk about Hardy Annuals.
These are capable of withstanding reasonably cold conditions without frost damage, and their seed germinates at a comparatively low temperature.
uses. In mass bedding schemes, when they are sown in situ in their flowering positions in blocks of one variety or genus. They have a slightly less formal appearance than half-hardy annuals.
In tubs and other containers.
As temporary flowering plants in between herbaceous perennials and shrubs and to fill in space until the permanent plants reach their required size.
The shorter ones can be used for edging if sown in a line at the front of a bed or border.
To provide temporary colour where the area is intended to be stocked with permanent plants at a later time.
advantages. Hardy annual seed is reasonably inexpensive and consequently the use of these plants is probably the cheapest method of stocking a garden.
Many of them make very good cut flowers.
No special equipment or skill is required to raise the plants from seed.
They provide a quick method of filling in a space colour-folly.
disadvantages. The ground into which they are sown must be as free from weed seeds as possible or the annuals will become weed infested as they and the weeds germinate together. On newly cultivated ground this is very difficult to ensure.
When they have to be weeded at the seedling stage, it is sometimes very difficult to distinguish the weeds from the hardy annuals. (This can be made easier by sowing the seeds in drills within the allotted patch instead of broadcasting it all over the surface. The straight lines of flower seedlings can soon be identified and anything else removed.)
Hardy annuals do not grow well if planted too thickly. This means that they have to be thinned out according to type when they are big enough to handle properly. This can be a fiddly job.
Many hardy annuals grow quite tall and will fall over and become untidy if not supported. The best method is to push twigs into the ground as soon as possible for the plants to grow through, but this makes it more difficult to weed round them, or to thin them out.
The majority of hardy annuals seed readily into the surrounding soil. This can be an advantage if you want them to keep coming up year after year but they can be as big a problem as the weeds if you do not want them all over the garden.
Generally speaking, they do not have as long a flowering period as most half-hardy annuals or bedding plants. Some continue to flower longer if they are regularly dead-headed, but this is a fiddly and time-consuming job.
Most of them do not like shady conditions.