GROWING SWEET PEAS: Uncommon in this area, planting these requires precision
by Virginia Ruschhaupt/Victoria County Master Gardener
November 10, 2024
PHOTO CONTRIBUTED BY RENEE SHEPHERD, RENEE’S GARDEN – Early Blooming Sweet Pea Velvet Elegance
PHOTO CONTRIBUTED BY RENEE SHEPHERD, RENEE’S GARDEN – Fragrant Sweet Pea, April In Paris
PHOTO CONTRIBUTED BY RENEE SHEPHERD, RENEE’S GARDEN – Heirloom Sweet Peas, Mermaid’s Dream
PHOTO CONTRIBUTED BY RENEE SHEPHERD, RENEE’S GARDEN – Sweet Pea Heirloom Painted Lady
PHOTO CONTRIBUTED BY RENEE SHEPHERD, RENEE’S GARDEN – Heirloom Sweet Pea, Perfume Delight
How many of your friends grow sweet peas in this area? I am betting not very many, although we may have fond memories of grandparents growing them. Sweet peas, Lathyrus odoratus, are climbing vines with tendrils and clusters of dainty flowers in a variety of colors, resembling fringed fluttering butterflies.
Their seductive fragrance resembles a blend of honey and orange blossoms. Some of today’s hybrids are not as fragrant as the heirlooms, but stems are stronger and colors more diverse.
Although this annual is part of the legume family, it is an ornamental flower and not a food crop.
Growing sweet peas is an art. Some people have the knack and others do not. I will share some information so that odds of success are in your favor.
Sweet peas thrive in cold weather and detest the heat. They are grown in USDA Zones 2 to 10, a vast temperature range requiring different planting times and methods. Gardeners in Zone 7 and below plant in the spring for summer blooms.
Since sweet peas will not survive our hot summers in Zone 8 to10, our option is planting seeds in November with expectation of blooms in late winter or spring. Our unpredictable winters won’t guarantee success every year, but with seeds at $5 a package, it’s worth the gamble to have a winter garden bursting with color and fragrance.
Sweet pea varieties are classified according to the hours of daylight required to bud and bloom. ‘Short day’ varieties can bloom in the short days of winter. ‘Long day’ varieties need 12 hours daylight. Unless seed catalogs state otherwise, assume varieties are ‘long day.’
Since we are growing our sweet peas in the winter, ‘short day’ varieties, Elegance and Early Multiflora series, are usually recommended. Are we limited to the ‘short day’ varieties? Seeking clarification, I called Renee Shepherd, sweet pea specialist and owner of Renee’s Garden.
See the photos for Renee’s recommendations. She encouraged experimenting with whatever cultivars appeal to us, with the warning that vines of ‘long day’ cultivars may be scrawny without much growth or foliage during our short days of winter. Be patient. Suddenly the right conditions will create a growth explosion.
Let’s get ready to plant. Sweet peas are heavy feeders, liking rich, moist, well-drained alkaline soil, preferably loamy and crumbly. Several weeks prior to planting, work in compost to a depth of over a foot. Adding bone or blood meal contributes to longer and better quality stems.
Planting seeds directly into the soil is preferable in Zone 8 and higher. Prior to planting, carefully nick the edge of the seed with the edge of a nail clipper, just enough to break through the seed coat. This nick allows seeds to absorb water and germinate quicker.
Plant in an area with full sun and some afternoon shade, but protected from north winds. Since sweet peas like their roots cool, mulch heavily once established and plant low-growing annuals beside them for shade.
The vines are heavy climbers, reaching 6 to 8 feet high. Tendrils attach to support, such as trellises, fences, or twine attached to posts. Set up supports prior to planting.
Persistently deadheading faded blooms delays seed formation, so that new blooms continue to form. Stop deadheading when leaves start turning yellow as spring temperatures increase. Now seeds can form for our next year’s crop, ready for gathering when pods are dry.
Sweet peas make great cut flowers for the vase. Include branches with leaves and tendrils to add a special charm to any arrangement.
I have selected seeds and am ready to plant this November. I hope you will try your luck also.
More about Sweet Peas
1. Plant seeds 1 inch deep and 2 to 3 inches apart. Water well. When seedlings are 2 inches tall, thin them 5 inches apart. When seedlings have 3-4 pairs of leaves, pinch off the top pair to encourage branching.
2. Snails and birds love the young seedlings. Place snail bait and netting while you are planting seeds.
3. Ideal Temperatures: 50-60 deg. for seed germination; 45-70 for growth; Can survive frost and even low 20s, dependent on growth stage.
4. Sweet Peas are poisonous. Do not plant in vegetable garden.
5. Insufficient water, temperature swings, or over-fertilizing, particularly too much nitrogen, can cause bud drop.
6. Soaking seeds is not necessary, and can cause fungal diseases.
7. Most Spencer varieties are not adapted to our climate.
REFERENCES:
1. Starting Sweet Peas from Seed – Horticulture Update (National Garden Bureau
2. Select the Proper Place to Plant Sweet Peas – AgriLife Today
3. Renee Shepherd, Renee’s Garden – Scroll to mid page for 9 links to articles and videos on sweet peas
4. Sweet Peas in Almanac
5. Sweet Pea Flowers: Planting, Care and Growing Guide in The Spruce