Many gardeners avoid using annuals as they consider them as too expensive, labour intensive and demanding for something which is only going to be there for one season.
They ignore the positive side of these cheerful colourproviders. I agree you need to make some effort (in most cases), but the reward reaped is huge. Few perennials will provide such a long flower display, or can supply the house with so many cutflowers as cosmos, the deliciously scented sweetpeas or the blue lace flower Didiscus caerulea. They are wonderful gap-fillers where early-performers such as bulbs have melted away, and are the perfect solution to empty areas between young trees and shrubs that are still some years away from filling out their allocated space.
Time to think
When we first arrived in our house in Coleshill, only fruit and vegetables were grown in the large back garden. Moving in during winter, we were confronted with a large expanse of bare soil. Very soon we took the decision to create a flowergarden near to the house, consisting of two herbaceous borders enclosed by a yew hedge. I was not clear in my mind yet what to plant and wanted to familiarize myself with the site first and get a feel for light. To gain time to think it all out properly, I filled the future borders with annuals. This was perfect: The instant effect was very rewarding as we enjoyed a summer-long display of colour and masses of cutflowers. In the meantime I could get comfortable with the space and develop the colourscheme that was to flow through the borders.
The advantage of growing annuals from seed is that it is a very quick and highly cost-effective way of obtaining many plants that can cover a large area, for the price of a packet of seeds. They can be used to fill a space not yet ready to be panted, to fill gaps where early-flowering pants such as bulbs leave a gaping hole for the rest of the season or fill pots on the terrace that will keep you company till late into autumn.
If you only need a few plants or want to grow lots of different ones I recommend buying them (if you can buy them, that is). A plant is not much more expensive than a packet of seeds.
Seeds of many annuals can be scattered directly in the bed, and they will get on with their life without too much further intervention from a gardener’s hand. Charmers like Forget-me-not, Cornflowers and Poppies belong to this group of plants, as do Nemophila and the Poached-egg-plant. The great advantage of direct sowing is not only that you have much less work, it is actually better for the plant as they can grow uninterruptedly and develop a good strong rootsystem that will be more drought resistant and will ensure a robust, longer flowering plant. Pricking out and transplanting seedlings will always check the growth of young plants. The drawback of direct sowing is that it is more difficult to keep a close eye on the seedlings. It is important to ensure sufficient humidity and it is hard to keep an eye on possible threats such as hungry slugs.
Some annuals, once established, will self-seed and need very little attention. Some plants will self-seed more readily than others. Poppies, Phacelia, California Poppy and Love-in-a-mist are some of the flowers that readily perpetuate themselves in your borders. Tobaccos and cosmos are shy candidates who, depending on temperature and humidity may reproduce themselves occasionally. They will need a little space and light to germinate and grow. The fuller your borders, the less likely they will return, though they might migrate to other areas of the garden where space is available. This dynamic aspect is what I love about these self-seeders.
I admit I prefer starting seeds indoors, where I can keep a close eye on them. But it is not only that I am worried something may happen to them outside, I confess I love the nurturing, pricking out and potting on of young seedlings. It is one of my favorite gardening tasks. Some annuals, such as Cleome and Zinnias need heat to germinate, so these seeds must be sown indoors. If you do not have the luxury of a greenhouse at your disposal, a windowsill will do too. You just need to be more vigilant and make sure the plants are healthy. Best is a not too warm north-facing window with a deep windowsill, so the plants can stand as near to the glass as possible. If you can put a mirror behind it to reflect daylight, the plants will grow up more straight. If not, you will have to turn them regularly to stop them from leaning towards the light too much. Move them out as soon as possible, hardening them off on frost-free, preferably overcast days.
Nowadays you can buy small heated propagators, like a mini-greenhouse. These are very convenient for seed germination and rooting cuttings, as the warmth comes form below, which is ideal.
Seedpackets contain all the necessary instructions, telling you when and how to grow the plants. Take your time to read these, and do not be tempted to start too early. Nothing worse than a window-sill full of young plants, eager to go out, which can’t because it is still to cold, or seeds that will not germinate because the soil is still too cold. The likelihood that they then get eaten by a hungry mouse or bird is big!
(See Catherine Thorpe’s Propagating Blog March 2021)
Dr Isabelle Van Groeningen
24th March 2023