Sweet Peas
by Michelle Le Strange, UC Master Gardener Advisor

I love planting sweet peas. There I said it. It's true. Every year these old fashioned flowers wake me up from winter and welcome me to spring. I find that sweet peas are easy to grow from seed, especially when planted in fall. Also, the flower show they provide is worth the effort of securing their little vines. Plant the traditional mixes, but be a little extravagant and try some antique varieties for their fragrance. You'll reel in the perfume every time you walk outside.

Sweet Pea Origins: Apparently it was the heavy aroma of the sweet pea growing in a monastery garden in Sicily that caught the attention of a Franciscan monk named Cupani. A bit larger than the wild sweet pea that grew on the shores of the Mediterranean, Lathyrus odoratus had deep blue lower petals (a part of the flower structure called the "standard") topped by purple upper petals (called the "wings"). However, it was the aroma and not the flower that was so appealing. The monk shared his discovery with a horticultural friend in Britain in 1696 and soon the seeds were spread far and wide.

About a century later breeders started playing around with the navy and purple flower to improve its looks. In 30 years' time they succeeded in expanding the color range to 250+ varieties of all different shades. Next step was to render the flower more florist-worthy. In other words, bigger blossoms with more flowers on longer stems. That's apparently when the strong fragrance of the sweet pea was forfeited for looks. The modern 'Spencer' hybrids are large, luminous, wavy petals and many flowers on long, bunch-able stems. They have only a mildly sweet aroma.

Fragrant Varieties: Sweet pea experts (people who obsess over sweet peas) spend hours combing seed catalogs for promising fragrant varieties. Thank goodness someone does because now some of their favorite antiques like 'Old Spice', 'Black Knight", 'Fairy Queen' and 'Cupani's Original' are making a comeback. Renee's Garden line of seeds offers several antique varieties, like 'Queen of Hearts', 'Blue Celeste', 'Perfume Delight', and 'Queen of the Night'. For something a little more floriferous than the antique peas, try the Old Royal series. They combine profuse blossoms, heat tolerance and impressive perfume in a range of colors that's heavy on the blues. Even 'Mammoth Mix' has a pleasing smell.

Support Systems: Most sweet peas require some vertical support. Slender wires work best, providing an easy grasp for tendrils. Chicken wire is the most common solution, but green wire fencing is more attractive. Sweet peas do very well on chain link fences and that support system is an easy and efficient way to grow sweet peas. Other methods are to lean the vines against lattice fencing or guide them up a sturdy tepee. Whatever support you choose, when the vines have climbed 18 inches or so, it's time to tie them up. Until that point, the tendrils seem to be doing a fine job of clinging, but the combined weight will eventually pull the plants down.

Growing sweet peas: You can plant sweet peas in containers, along fence lines, mingled with star jasmine and other climbing vines on trellises, or along the side of a garage or shed. The dwarf and "knee high" varieties are perfect for beds and borders and need no support. You can plant thinly or pack the seeds snuggly in rows leaving only an inch between vines. It all depends upon space and proximity to the support fencing. Transplants are also available at nurseries. If you crowd them in a container, feed them every two to three weeks with a mild fertilizer like triple 16 (16-16-16) or a soluble fertilizer for blooms. When sown in the garden they need a little fertilizer, but not a lot, especially if the planting bed has been amended with compost and humus.

Sweet peas require frequent watering to keep their soil cool and moist. So planting them in fall and letting them grow during our foggy wet winters is perfect timing. As temperatures start to warm in spring the sweet peas are ready to start blooming and will continue to look good and thrive until temperatures reach the upper 70s. As summer approaches sweet peas stop producing flowers and the vines dry out. Pulling out spent vines is hardly a chore thanks to the shallow root system of the sweet pea.

October 16, 2003