Sweet Pea

Lathyrus odoratus
Family: Leguminosae
Genus: Lathyrus
Species: odoratus

It’s true of gardeners that one digger’s bromeliad is another’s fava beans. That’s a very mixed way of saying, metaphorically, that each of us is likely to have a strong opinion about what’s attractive in the plant kingdom and what’s not. But no matter if our tastes run to the exotic or the familiar, most of us agree that the sweet pea is…well, just about the sweetest little flower we can think of. Nearly everyone has a memory associated with sweet peas. It’s usually sensory, often involving fragrance and sometimes meshed with grandmothers, lavender, and talcum powder. Others among us might be reminded of Gregor Mendel, his work in genetics, and the sweet pea’s important place in the annals of science. Its name has been used as a term of endearment, and not just by Popeye and Olive Oyl. These sweet little blossoms are beloved by just about everyone. Many of us grow them not so much for their appearance in our gardens as for a continuous supply of bouquets in our homes. They are attractive in the garden, to be sure; particularly if they’re the short-lived focal point of an old-fashioned floral “room.” But most of us cultivate them so that we can bring those flowers into the house.

L. odoratus is an annual, moderately fast growing, that thrives in the cool, moist climate of spring. Heat is anathema to sweet peas, so don’t plan to enjoy them in the height of summer, even in the Northwest. They are easy to grow from seed and make a wonderful garden project with young children. To hasten germination, try soaking the seeds for a few hours just before you plant them. Another trick is to scruffle up the seed coating a bit with an emery board. Some gardeners put their sweet pea seeds in the freezer in the fall before planting them in early spring. Others plant them in the ground in the fall and do mild-weather dances, in the hope that the little seedlings will poke their heads up in late winter. Some start their seeds between layers of moist paper towels, others use seed flats or peat pots. Some devoted fans maintain a sweet-pea trench, one foot wide and as deep, that they recondition every year, digging in compost, peat, and the appropriate amount of a complete, balanced fertilizer before putting in seeds, one inch deep and two inches apart, in March. The hardest part of this is thinning the seedlings to six inches apart. Ouch!

There are recognized categories of Lathyrus odoratus, distinguished by bloom times or growth habit. Plant hybridizers have had a field day with sweet peas. Gregor Mendel certainly picked the right plant for the right job! The six-foot, weak-stemmed plant that climbed by tendrils in its native Sicily was seized upon by the English, who were captivated by the fragrance of its small flowers. After 250 years, we now have early flowering, spring flowering, and summer flowering varieties. All of these are climbers. Many have intense fragrance. They come in all colors but yellow. The early-flowering varieties will bloom in late winter in frost-free regions; and despite the name, the summer-flowering varieties are merely heat resistant. They have the largest flowers and are at their best in early summer. The bush varieties of sweet peas are vines as well, but they have been bred to have predetermined growth. They require no support, ranging in height from 4 inches (‘Cupid’) to 2 ½ feet (‘Knee-Hi’). Several of these varieties have little or no fragrance so if you want that scent, read the seed package or plant description carefully. If you choose a climbing variety, be sure to put in your support system before you plant the seeds. A free-standing system is best. Try not to grow your sweet peas against a wall. The decreased air circulation will make powdery mildew all the more likely.

Give sweet peas full sun, good soil, and even moisture. Don’t let them dry out. Guard the tender little seedlings from slugs, and pinch them (the seedlings, not the slugs) to encourage branching. Pick off the spent flowers regularly—twice a week is not too often—or blooming will stop. And do warn the small people in the area that these pea pods are not for eating.

Now if you’ll excuse me, I have sweet peas to plant. Legend has it that sowing sweet-pea seeds before sunrise on St. Patrick’s Day will give you the largest and most fragrant blossoms. I’ll be out before dawn planting sweet peas, just before I put the corned beef on to simmer…but if I were to miss this window, I could plant my sweet pea seeds by early April and still have flowers to enjoy this year.