Grow hardy annuals from seed this autumn or next spring for a garden full of summer colour
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| Choose Nigella for its flowers, foliage and impressive seed pods
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'The sole purpose of annual plants is to take advantage of warm, moist conditions to grow quickly and then produce lots of flowers so that large quantities of seed can be produced before the plant dies.'
'Hardy annuals are the ideal plants to start off from seed as they are so undemanding, with the added bonus that any seed left to fall to the ground will probably germinate the following year without any extra help from you.'
Hardy annuals are plants that are used to our cool climate and will grow quickly from seed sown outside, or in a coldframe or cold greenhouse in autumn, or outdoors in spring. They will flower and then die, all within a year. They are ideal plants for starting off from seed as they are so undemanding, with the added bonus that any seed left to fall to the ground will probably germinate the following year without any extra help form you.
Autumn sowings
Not all hardy annuals are suitable for sowing outside in autumn, but poached egg plant (
Limnanthes douglasii), California poppies (
Eschscholzia),
Calendula officinalis,
Papaver somniferum and
Centaurea cyanus are some that are. September sowings will get you going earlier and result in earlier flowers and colour. Sweet peas are another good option for autumn.
Nigella
Nigella, or love-in-a-mist, is a really popular hardy annual on all counts. The pretty, blue flowers are supported by a green filigree ruff and have a distinctive central structure which later expands into the rounded seed case. The foliage is also finely cut, like fennel, making it a very delicate-looking plant, but one that is tough enough to survive a British winter.
Sowing direct into garden soil
You can start off your seeds either by sowing directly into the garden soil, or by sowing into containers then planting out later.
It is easy to sow seeds directly into garden soil, but you will get better results if you give them early care and attention. First, choose a sunny spot where there is space for the flowers to grow.
Whether you sow in September or in spring (late March to April), wait until a fine day, lightly dig over the area with a fork, then rake the soil several times to break down the lumps to about the size of chickpeas. The seeds have a much better start if the germinating roots can easily search through the soil for water and the shoots can break through the fine crumb to reach the light. Then, sprinkle the seeds evenly on the surface, gently rake the soil again to lightly cover them, and water them in carefully.
Sowing thinly in rows to detect weeds
This method often encourages weeds to germinate along with the seeds and it can be difficult to recognise what to keep and what to remove. Alternatively, sow the seed thinly in rows so that random weed seedlings are easier to spot. Once the seeds have germinated and grown three or four leaves, they need to be thinned out to allow each plant space to develop into a strong plant. They can be thinned in two stages, but need a final a spacing of about 20-30cm (8-12in). If you don't thin, the plants will be much less vigorous and probably finish flowering earlier than expected.
Starting off indoors in compost trays
The second method is to sow the seeds thinly into trays of compost and start them off inside on a windowsill in April. Once the seedlings appear a few days later, they can be pricked out singly into pots and grown on into vigorous plants. Alternatively, you can sow the seeds into modules and then transplant into individual pots. Then plant in the soil at the same spacing as before.
If sowing hardy annuals in autumn under cover, choose a cold frame or cold greenhouse. You don't want heat, but you do want a frost-free environment. Outside sowings may benefit from a covering of fleece.
Although sowing indoors is more fiddly at the start, the seedlings are protected from pests and the plants are stronger when planted out, as they are competing less for moisture and space. This method is also better if your soil is clay-based, is late to warm up and refuses to rake down to a fine crumb for seed sowing.
Seeds of annuals
The sole purpose of annual plants is to take advantage of warm, moist conditions to grow quickly and then produce lots of flowers so that large quantities of seed can be produced before the plant dies.
Once the plants start seeding, flowering will be reduced, so by removing the developing seedheads, flowering can be prolonged. This can be quick and easy with some annuals, like sweet peas, and less so with others, such as the poached egg plant (Limnanthes douglasii). Either way, allow some seeds to develop as flowering peters out, then either collect and store them until next spring, or let them fall to the ground and take their chances.
Site, soil and spacing required
Hardy annuals are fast growers, so enjoy a sunny site where they are not crowded out by other plants. They are often said to thrive in poor soils, but many will grow into more free-flowering, robust plants if grown in a soil enriched with organic matter – but they often dislike wet soils.
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| Poached egg plant (Limnanthes douglassi)
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Allow each plant its own space and reduce competition by carefully thinning out seedlings. Stake or support tall varieties, such as sweet peas, cornflowers and sunflowers, and deadhead to encourage more flower buds to develop.
Other popular hardy annuals
Calendula officinalis – pot marigold
Centaurea cyanus – cornflower
Cerinthe major purpurescens – honeywort
Eschscholzia californica – californian poppy
Helianthus annuus – sunflower
Lathyrus odoratus – sweet pea.
Limnanthes douglasii – poached egg plant
Nigella damascena – love-in-a-mist
Papaver somniferum – opium poppy
Tropaeolum majus – nasturtium
Hardy annuals for attracting insects
Calendula officinalis – attracts beneficial insects that eat aphids
Cerinthe major purpurescens – attracts bees
Convolvulus tricolor – attracts beneficial insects that eat aphids
Limnanthes douglasii – attracts beneficial insects that eat aphids
Scabiosa atropurpurea – attracts bees and butterflies
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