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An annual plant is a plant that completes its life cycle within one year.
Many popular fruit and vegetable crops in a kitchen garden are annual plants, as are a range of common bedding plants or flowers.
Annual plants are typically grown from seed, though they can also be purchased from garden centres and nurseries as plugs or pot-grown plants ready to place in your garden.
A biennial plant is defined as a plant that completes its lifecycle over two years – growing in the first year before flowering and setting seed in the second.
Unlike perennials – annuals and biennials will not remain in place in your garden over multiple years, however, in the right conditions, certain annuals and biennial plants will self-seed readily.
This means that the seeds will naturally mature and disperse around the growing area in which they are planted and if you leave them to self-seed, this does of course mean that you can continue to enjoy them in your garden year after year.
The benefit of including annuals and biennials in your garden is that you can ring the changes. If you do not choose readily self-seeding varieties then you can opt to grow different flowering plants or other annual plants every year.
Asters / Begonia / Borage / Calendula / Calibrachoa / Cineraria / Cleome / Cornflower / Cosmos / Diascia / Echium / Euphorbia / Foxgloves / Geraniums / Impatiens / Leeks / Lunaria / Mangetout / Marigolds / Moonflower / Nasturtium / Nigella / Pansies / Persian Buttercups / Petunia / Poppy / Radishes / Salvia / Sunflower / Surfinia / Sweet Alyssum / Sweet Corn / Sweet Peas / Tickseed / Viola / Zinnia
Annual plants will not typically come back every year. Usually, you will have to sow new seeds each year or purchase new bedding plants in order to continue to enjoy them in your garden.
There is an exception to this, however – when some annual plants are provided with the ideal conditions, they will self-seed readily. In other words, their seeds will naturally mature if you let them.
They will drop to the soil nearby or be dispersed through your garden via natural means. Those seeds should then, if they have the right conditions, germinate, and new plants will grow, usually the following spring.
Some annuals that can self-seed readily in the right conditions include Borage, Calendula, Cornflowers, Nasturtiums, Poppies and more.
Bear in mind that certain flowering plants may not come true from seed, or may take over your garden if you do not prevent them from self-seeding.
Often, annual flowering plants are deadheaded, which of course prolongs the flowering season, but prevents seed formation from occurring.