Self-sowing plants lend gardens a natural charm — until they become weeds
THERE are many plants that self-sow in the garden to a greater or lesser extent. They are also widely known as self-seeding plants.
But all plants are self-seeding — there is no other way of making seeds, but there are varied ways that seeds, when shed, can be transported to another location and germinate there. Such agents include wind, water, insects, birds, animals, the mud on cars and dispersal and sowing by people.
Deliberate sowing, and accidental sowing, by people is probably the most effective, at least geographically, as it has been the way many plants have been dispersed globally. And most of these agents are in action in the garden too.
Seeds of self-sowing plants are usually produced in large numbers and find their way to suitable growing sites by means of the dispersal agents mentioned.
This habit of popping up in all the right places is very charming and was part of the charm of old-style cottage gardens, some of which still exist with the addition of more modern plants such as African daisy.
California poppy, candytuft, calendula, honesty, poached flower, poppy, cornflower and evening primrose are annuals or biennials that self-sow readily — even though none of them is native. They are mostly American flowers from drier parts of the western states.
Granny’s bonnet, dierama, lady’s mantle, Mexican fleabane, red valerian, dame’s violet, dusty miller and lamb’s ear are perennial flowers from other countries. All are, more or less, enthusiastic selfsowers. Foxglove, bluebells, wild garlic, viper’s bugloss or echium, mullein or verbascum and teasel are wild native plants, or garden escapes, that find their way into gardens and can lend a garden a lovely natural touch, popping up here and there.
Bluebells and wild garlic have bulbs that sustain them over the dry summer months but they produce massive quantities of black seeds to spread themselves about.
The foxglove, verbascum, echium and teasel are natives, colonisers of recently cleared spaces, growing rapidly and making lots of seeds to carry on the genes.
An American native, fringecups or tellima, is often mentioned when self-sowers are discussed. It crosses the line from charming self-sower to prolific weed in a couple of years and becomes a real problem coming up from seed for years, even after every plant is taken out.
Some of the others — lady’s mantle, for instance — can be a problem too. If this is beginning to happen with any of these plants, pull out excessive numbers of seedlings and cut out the spent flower stems after flowering, but before the seed is ripened and shed.