CHELSEA Flower Show week is drawing to a close. More than 150,000 visitors will have filed past the magnificent show gardens. The stewards quickly gen up on the attention-grabbers, spelling out their Latin names and dishing out brief care notes.
I have noticed that one piece of horticultural information which rarely goes down well is: “It’s a biennial.” The thought of nurturing a plant for it to die after flowering in its second year seems an anathema to many. This is a shame. Biennials have evolved to grow as leafy plants in their first year, building up reserves to expand into flower quickly the next. They tend to be hardy subjects, shrugging off late-spring frosts. They exploit that niche in the year when deciduous trees and shrubs cast a veil rather than a curtain over the sun, and they fill spaces later to be taken over by the “live fast, die young” annuals and lolling herbaceous perennials.
For Chelsea designers, many biennials are staples for colour and drama at this cusp between spring and summer — no more so than this year, when many of the show gardens had the feel of a woodland edge, the natural habitat of so many biennial wildflowers. Think of forget-me-nots and foxgloves.
Jo Thompson used angelica in the garden that she designed to celebrate Josiah Wedgwood, founder of the pottery. Angelica archangelica develops long roots in its first year beneath a small clump of large mid-green leaves divided into leaflets that usually reach about 60cm in height. This is in readiness for the grand finale in year two, when it sends up a stout branching stem, up to two metres in height, bearing broad umbels of pale green cow-parsley-like flowers.
Honesty, with its papery coin-like seed-heads, has an old-fashioned air about it, but there are some modern selections that are that bit different. Lunaria annua var. albiflora “Alba Variegata” looks like the straight species in its first year, with plain green seedling leaves, but, in the second year, white flowers and white frosting on the leaves add a dappled effect to planting in a semi-shaded spot. In contrast, Lunaria annua “Chedglow” has deep-purple leaves and magenta flowers, which make a lovely contrast with the fresh greens of late spring.
Hesperis matronalis var. albiflora, the white-flowered form of sweet rocket, which has lilac flowers, is an easy way to add height and a splash of cool white to a semi-shaded area. The flowers, which are attractive to beneficial insects, emit a deliciously sweet perfume into the evening air around Whitsuntide. And, like honesty and angelica, it will self-seed.
So, if you admire a plant and learn that it is a biennial, don’t dismiss it. Act now while you are inspired. The next six weeks is the ideal time to sow for you to enjoy its floral climax in your own garden next year — and, with a little selective weeding, many more beyond.