Their prettiness, perfume and abundant flowers have made sweet peas popular with gardeners and florists for a long time
You could, on first glance, be forgiven for mistaking its plump, spherical seeds for peppercorns, given the fact that they are of roughly the same size and colour. But the similarity ends there, because no peppercorn has ever grown into anything as delicately beautiful or as deliciously fragrant as a sweet pea plant in full bloom.
That winning combination of prettiness and perfume means that this remarkably floriferous annual – whose Latin name Lathyrus odoratus celebrates its intense scent – has long been a favourite of gardeners and florists.
Records of its cultivation can be traced as far back as the 17th century when a Sicilian monk by the name of Francisco Cupani gave a written description of a sweet pea with deeply perfumed, purple/maroon flowers.
Seed from Cupani’s plant soon winged its way from Sicily to England, where it quickly excited the interest of botanists, plant breeders and gardeners.
By the late Victorian era, the famous British sweet-pea hybridiser Henry Eckford had produced more than 100 varieties of the type that became known as the grandiflora sweet pea, all of which retained the intense scent of Cupani’s flower but produced larger flower spikes in a range of jewel colours.
A few years later, in 1901, came the frilly-petalled, bright-pink L. ‘Countess of Spencer’, the very first of the long-stemmed, very large-flowered Spencer sweet peas, so called because they were bred by Silas Pole, the head gardener of the Earl of Spencer at Althorp.
Today, as a result of the work of Eckford, Pole and many, many other plant breeders of the 19th, 20th and 21st centuries, such as Dr Keith Hammett, there are countless varieties of sweet pea in cultivation, including 60 that hold the Royal Horticultural Society’s much-coveted Award of Garden Merit (AGM).
A baffling range of new varieties continues to be introduced. Some including ‘More Scent’ are prized for the intensity of their perfume, others such as ‘Almost Black’ are grown for the intensity of their flower colour, while others including the multiflora ‘Mammoth’ series are grown for the number of flowers they produce per stem.
Varieties such as the ‘Winter Sunshine’ and ‘Solstice’ series have specifically been bred to flower very early when grown under glass, while the Cupid series are valued for their compact growth habit and suitability for container growing.
The result is an embarrassment of riches where it’s all too easy to spend long, enjoyable hours browsing the catalogues of specialist seed suppliers.
That said, there are some enduring favourites including the magenta-flowered, strongly scented L. ‘Gwendoline’ (AGM) and mauve-flowered L. ‘Sir Jimmy Shand’, both popular varieties with those Irish gardeners who skilfully grow cordon-trained sweet peas to competitive show-bench standards.
Among them is Chris McAleer, the Balbriggan-based organic gardener and former All-Ireland sweet pea champion (yes, there is such a thing) who has also won some acclaim as the breeder who introduced the award-winning variety L. ‘Bridget McAleer’ (named after his wife) into cultivation.
Rather than wait until springtime to sow his sweet pea seeds, as some gardeners do, McAleer is a very firm believer in the benefits of an October sowing, where the reward is far stronger, more vigorous and floriferous plants that come into flower earlier, stay longer in flower and are more tolerant of difficult growing conditions.
“I generally sow seed in the first half of October, after soaking them overnight indoors in a small container of water and then spreading them out on a few sheets of wet kitchen paper to pre-sprout them,” he says.
“Once sprouted, the seed goes into root trainers or pots filled with a mix of spent garden compost and garden soil, which I move straight away to my unheated glasshouse to overwinter.”
Aside from an exceptionally harsh frost (offer some extra protection when temperatures fall below -4 degrees), McAleer agrees that the greatest risk to autumn-sown sweet pea seed comes from mice. Sweet pea seed may be toxic in large quantities to humans in whom it causes a condition known as osteolathyrism, but these rodents love nothing more than to feast on it, so take suitable precautions.
The young seedlings will also require regular watering, enough to maintain steady growth but never to the point where the compost is sodden.
Grown ‘hard’ so that they gradually become accustomed to low winter temperatures, autumn-sown sweet pea plants are surprisingly resilient and can transplanted out into their permanent position in the garden in mid-March or early April, just so long as the soil is not sodden or frozen.
Give them a well-prepared, sunny spot, where the soil is weed-free and has already been enriched with manure, seaweed or pelletted chicken manure. Take precautions against slug damage too and provide sturdy supports for the plants.
All going well, you should be enjoying the sight and smell of your first sweet pea flower by early June.
That is definitely something to look forward to in the dark winter days ahead.
Specialist sweet-pea seed suppliers include Owl’s Acre Sweet Peas (sweetpea-seed.com), Somerset Sweet Peas (somersetsweetpeas.com) and the Northern Irish Cooltonagh Sweet Peas (cooltonagh.co.uk).
Wednesday, October 16th: Wesley House, Leeson Park, Dublin 6 at 8pm: RHSI gala flower arranging demonstration given by international demonstrator James Burnside, as a fundraiser for next June’s WAFA show. For further details, tel: 01-235 3912 or see rhsi.ie