Nothing says ‘summer’ like a sweet pea, and for vigorous, healthy, floriferous plants, it’s important to get them off to the best possible start. Here, Roger Parsons offers his expert advice on sowing technique and general care
Of all the sweet peas, ‘Cupani’ is probably the most fragrant. This old-fashioned, short-stemmed variety has modest yet beguiling cerise and purple petals, and renowned breeder Roger Parsons gives it a score of six out of six for scent. It’s reputed to be the original sweet pea sent in 1699 by Francesco Cupani, Sicilian monk and naturalist, to a cleric, Dr Robert Uvedale of Middlesex. “Actually, it was introduced in the 1990s,” says Roger, gently but frankly, in the way of specialists everywhere. “‘Matucana’ also has this attribution, but they’re both improved forms of the wild species Francesco Cupani sent over.”
Roger Parsons, holds the National Collection of Sweet Peas (Lathyrus odoratus) and other Lathyrus species, comprising over 1,300 types. Roger and his staff not only maintain this collection, but also grow for seed and new cultivars, harnessing the vast gene pool available to them to develop new varieties.
Spencer types are by far the most popular sweet peas with their longer stems and big frilly flowers. “They have been developed for cutting or exhibition; they don’t produce many side shoots and they’re grown as cordons,” Roger says. “All their energy goes into producing big flowers.” For garden decoration, Roger recommends the old-fashioned and intermediate types: they bear more side shoots and so bush out somewhat and bear flowers all the way down the plant – not only at the top.
Stem length, which tends to shorten as the season progresses, is largely down to the type of sweet pea you grow. Garden lore dictates that removing the tendrils results in longer stems, but Roger insists this makes no difference. “The tendrils can wrap around adjacent stems and bend growth though,” he notes, “but if you grow them up pea sticks, you’ll need the tendrils.” If you’re growing for display, let them climb an arch or a cylinder. “On a wigwam, plants become congested as they reach its narrow top,” Roger explains. “If you like an informal style, you could just let them use other plants for support. Semi-dwarf types need little to no support.”
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