Sandy’s Garden ...Everlasting Sweet Pea

Sandy Simpson
Sandy Simpson

We – my wife and I – are supposed to know better than buy plants on impulse in garden centres.

We are supposed to know that, before we as much as think of visiting a garden centre, we should consider our soil type, the location in the garden for which we are looking for plants and the purpose which the plants are to serve - whether they are to fill gaps in our planting schemes or to be architectural plants; to be grown primarily for their flowers or for their foliage; and whether we are looking for annuals or perennials – among other considerations. In short, we really should have decided which plants we want and go to the garden centre armed with a shopping list in exactly the same way as we would prepare for a trip to the supermarket. We know we should always do this; we do sometimes prepare in this manner: but we are also guilty of impulse-buying because we see something we like or because one or other of us ‘has always wanted one ...or some … of these.’

So, when we saw everlasting sweet peas in a garden centre in the middle of March, my wife refreshed my failing memory. “I’ve always wanted these,” she said, “and we never seem to see them before the end of the summer when they are well past their best and looking very sorry for themselves.” I don’t know if you, gentle reader, have ever heard plants call out, “Buy me! Buy me!” But my wife has – and these pots of everlasting sweet peas were positively shouting at her. And, to be fair, they were at least whispering to me as well.

Lathyrus latifolius … to call the plant by its proper botanical name … is a fast-growing, climbing, herbaceous perennial - a plant that has no persistent woody stem above ground but that, having died back in the autumn, reappears year after year in the spring. Lathyrus latifolius … it copied its botanical name of Lathyrus from the Greek name for the pea, while latifolius means ‘broad-leaved’ … is commonly called the everlasting sweet pea, perennial peavine, perennial pea, broad-leaved everlasting-pea, or just the everlasting pea. Native to many parts of continental Europe and to North Africa, it has been spread to many other parts of the world and has found North America and Australia very much to its liking. A hardy plant, it does best in full sun or partial shade, being happiest in a south-facing or southwest-facing situation and preferring fertile, moist, but well-drained soil, although it is not fussy about the pH level … the acidity or alkalinity … provided it is not too far away from neutral. Within a couple of years of being planted it will have reached its maximum height of between 1½ and 2½ metres … say between 5 and 8 feet in old money … and its maximum spread of between half a metre and a metre. In most gardens it should be given adequate support and grown as a climber on a wall, fence or trellis, although people with the space for this might allow it to scramble over banks and slopes. Some gardeners let it climb through the branches of a substantial, evergreen, early-flowering shrub.

In flower from July to September, different cultivars carry attractive, unscented, pink, red or white flowers, which are hermaphrodite … have both male and female organs … and are pollinated by bees; the seeds ripen from August to October; and the plants should be cut back to ground level in the autumn. Although perennial sweet peas are pretty tough, they are susceptible to being attacked by aphids, slugs and snails; and they may be affected by powdery mildews. However, the gardener will find Lathyrus latifolius very difficult to evict!

The flowers are said to taste sweet and crisp, but I wouldn’t recommend trying them for the seeds contain a toxic amino acid that can cause a severe disease of the nervous system.