The fragrant, sweet aroma that is released by the blossoms of annual sweet peas (Lathyrus odoratus) gives them their name. The fall, winter, and early spring garden seasons in warm, Mediterranean settings are perfect for this annual flowering vine because it prefers mild temperatures. In the spring and early summer, sweet peas grow best. Plant hardiness zones 4 through 7 of the United States Department of Agriculture are suitable for perennial sweet peas (Lathyrus latifolia). Depending on the cultivar, sweet pea blossoms come in a variety of hues, including white, purple, pink, red, orange, blue, and lavender.
How quickly do plants for sweet peas grow?
- Sweet peas can be seeded in the fall in warmer places (Zone 7 and above) where the winters are generally not too harsh. Other than that, plant seeds in late winter or early spring. Before planting, give the seeds a 24-hour soak in water. By doing so, the seed coat is softer and the sprouting process is accelerated.
- Fill your planting containers with high-quality potting soil while the seeds are soaking. Use the deepest pots you can find because sweet peas develop a lot of roots. Ideal containers are 4-inch (10-cm) pots and root trainers.
- In each container, plant two seeds by pressing a fingertip into the soil and a half-inch (1.25 cm) deep.
- To boost humidity and hasten germination, cover pots with a plastic dome covering. Place in a warm greenhouse or a house window with good light.
- Pinch out the center growth tip, just above a leaf joint, once plants are 4 to 6 inches (10 to 15 cm) tall, leaving just two or three leaf nodes. The plant will be encouraged to branch out strongly from the base as a result.
- Because they use a lot of food, sweet peas need a little more care to produce in large quantities. Apply bone meal, a thick layer of compost or well-rotted manure, and a generous amount of natural fertilizer to planting beds to prepare them. Incorporate these elements thoroughly into the soil.
- Vines require a sturdy foundation to climb and grow quickly. Affix Hortonova netting or 6-foot (1.8 m) tall metal fence to the tall poles spaced approximately 8 feet (2.4 m) apart down the row for them to climb.
- Around the time of the final spring frost, plant seedlings outdoors in two rows, one on either side of the trellis, spaced approximately 8 inches (20 cm) apart down the row. It’s crucial to keep the vines bound to their supports as they erupt into lush growth. Sweet peas can grow more than a foot (30.5 cm) per week once the vines begin going.
- Sweet peas adore water, and they can’t survive without regular watering. Set up soaker hoses as soon as you plant them to prevent their luxuriant development from being restrained. It’s important to maintain their thirst quenched during warm weather. Use diluted fish and seaweed emulsion to feed plants once a week.
- Pick flowers when there are at least two unopened blooms remaining on the stem for the greatest vase life. To extend the life of the vase, add flower food to the water. It’s crucial to prevent plants from going to seed in order to prolong blooming, so be sure to regularly harvest and deadhead the flowers.
How long do sweet peas take to sprout?
To avoid mildew, sweet peas require a location in full sun, rich soil that drains very well, and sufficient air circulation. Increased organic material must be worked into clay-rich soil in order to improve drainage. Consider using raised beds for successful results if the soil is excessively wet.
If you are aware that summer heatwaves can come on suddenly, plant your sweet pea seeds where there will be some afternoon shade. For best results, carefully read the instructions on the seed packet. Proper plant spacing is essential. Slugs and snails should be kept away from seedlings. Use netting suspended over seedlings until they are 4 to 5 inches tall if marauding seed and seedling-eating birds are an issue.
Adequate water is a crucial requirement for all sweet pea varieties. If summer rain is insufficient to keep them evenly moist, be sure to water germination-stage seeds, seedlings, and vigorously growing older vines on a regular basis. If the soil is dry when your finger is inserted up to the first joint in the soil bed, water the plants.
Sweet peas are strong feeders, so add plenty of rich compost or well-rotted manure to the soil before planting. At least twice during the growing season, fertilize the soil with a thorough soil drench made up of one tablespoon of liquid kelp and one tablespoon each of fish emulsion. (Every few weeks, sweet peas grown in containers require regular fertilization.)
Aphids can be a problem for sweet peas; spray them off frequently with water. Sticky pheromone traps placed among the vines to attract and capture thrips, an opportune pest, can be used to efficiently control them. Mildew can be avoided with enough airflow and by not watering in the late afternoon and evening ( until the plants succumb to it naturally at the end of their bloom period.)
Almost any vertical support structure will allow all tall vining kinds to naturally grow up it. They will develop into strings, netting, wire, wooden, or pretty much any other sort of trellis. In the soil you can also utilize long branches that were left over after tree pruning. Wrap them in twine or netting so the tendrils can grip because they cannot twine around heavy poles like bamboo. It’s usually advisable to stay away from wire fencing in really hot climates like Texas. Before you sow the seeds or once they are a few inches tall, erect your securely anchored supports.
Between 75 and 85 percent of sweet pea seeds will germinate. There is always a little fraction that goes dormant, giving Mother Nature a refuge in the wild in case of bad weather. Only plant the seeds that have swollen and soak them in tap water for no longer than one night prior to planting in order to leave out the dormant ones. Never soak seeds; rather, nick them to let moisture seep into the seed coat for the highest possible germination rates. To accomplish this, simply cut a small hole with nail clippers in the seed’s outer layer; no chunk needs to be gouged out; this will allow moisture to enter the seed naturally. Although this nicking procedure takes more time, it will ensure excellent germination.
Plant seeds 2 to 3 inches apart and 1 inch deep. Depending on the climate and soil temperature, seeds can fully germinate between 10 to 28 days. Dig down to check if the seeds are still present if your sweet peas do not germinate well. Plant more immediately soon if they have decayed or been eaten since they will quickly catch up. It’s crucial to thin seedlings when they are several inches tall so that they stand about 5- 6 inches apart. This will provide the plants room to develop and flourish. Pinch off the top set of leaves when seedlings have three or four sets to encourage plants to branch out. Avoid significant changes in soil moisture during the active growing season by keeping sweet pea plants evenly moist. Mulching is a wise tactic.
Picking bouquets early and frequently can help you enjoy the longest season of spectacular bloom; the less you pick, the later the plants will go to seed and wither. Harvest flower stems frequently as the lowest blossom on each stalk just starts to open. Although stems may get shorter as the season goes on, the flowers are still large and gorgeous.
Sweet Peas Species
Our common garden sweet pea is the annual species Lathyrus odoratus; you can find them in a variety of colors and growth patterns, including:
tall varieties of vines
Depending on the region and season, these robust vines can grow to be 5 to 10 feet tall and produce numerous flower stems over a six to eight week bloom period. Tall vining plant species come in a variety of floral shapes:
Intense breeding efforts have been made in England to produce tall vining “Spencer” cultivars with bigger, waved and ruffled exquisite flowers. Because English breeders typically have been more focused in petal shape, form, stem length, and color than in perfume or weather tolerance, some Spencers are quite fragrant while others are very faintly so. Nowadays, Spencer kinds can be used to describe the majority of large-petalled, ruffled sweet pea cultivars. We stock the scented Spencer type “Blue Celeste.”
Mammoth and Royals are two American cultivars developed in the middle to end of the 20th century that have good-sized flowers, a light perfume, and are widely available. Since our only area of expertise is scented sweet peas, we do not provide these varieties.
Variety of Containers & Window Boxes
These tiny plants look great in containers and have stems that are 8 to 10 inches in length or have spreading and mounding characteristics. The heirloom varieties “Windowbox Cupid” and “Cupid Color Palette” are available from us.
Short, unable-to-climb Dwarfs
These sweet peas are short and don’t require vertical supports, with some varieties being tendril-less. It’s “Explorer” for us.
Other Species of Sweet Peas:
In the West, the perennial Lathyrus latifolius is frequently observed as a naturalized roadside wildflower. The cultivated form of this perennial, which is far more drought tolerant than annual sweet peas, can be trained to grow into an appealing and dependable permanent hedge plant. Although the flowers are plain, small, and odorless, their shape makes me think of miniature orchids. They come in rose, pure white, and shell pink. We market these colored mixtures as “Garden Orchids.” In zone 4 at Sweet Pea Gardens in Surrey, Maine, where they are quite hardy and over ten years old, Susan Keating has planted perennial sweet peas as a tall blooming screen on the side of her garage. Their flowering stalks also make lovely arrangement flowers.
This diminutive sweet pea, Lathyrus sativus azureus, features 1 inch dazzling azure-blue flowers and tangled grassy leaves. Plants only reach heights of 3 to 4 feet. attractive landscape accents in pots with minimal supports. We offer “Electric Blue” for sale.
Dr. Hammett is attempting to stabilize hybrids between several annual species in order to bring together lovely form and scent with fresh colors and heat tolerance. For home gardeners, the next ten years will bring some interesting new advances, such as real tricolor sweet peas and non-fading orange and apricot colours, all of which have potent fragrances.
Sweet Peas in Containers
Gardeners with patios, decks, or merely tiny gardening spaces can take advantage of the short, mounding kinds of sweet peas, like “Color Palette,” to enjoy their beauty and delicious smell. These small vines, which only reach a height of 8 to 10 inches, have delicately cascading branches and fragrant blossoms. A rose-pink and white bicolor as well as a combination of lavender, pink, dark purple, and mahogany are among the colors. Plant seeds immediately in deep containers with a minimum 8-inch diameter or rectangular window boxes with a minimum 6-inch depth in the very early spring. Always place seeds in planting containers 1 inch deep and 3 inches apart, in uniformly pre-moistened, high-quality, fresh potting soil. Germination takes 10 to 28 days when kept uniformly wet and in full sun.
Make sure to thin seedlings to 4 inches apart after they reach 2 inches in height (so, for example, you would leave 4-5 evenly spaced plants in a 12 inch in diameter container.) Plants can spread out and expand as a result as they get older. It’s crucial to remember to fertilize container sweet peas frequently (every two weeks) and to maintain them well-watered. Defend plants from snails and slug damage. Remove faded blossoms on a regular basis for the longest bloom. Mulch your containers and provide them with afternoon shade during the summer to extend their bloom.
Are sweet peas trellis-required?
- A tough seed coat covers the sweet pea seed. Before planting, immerse the seed in water to promote germination.
- In the early spring, direct sow seeds in normal soil with full sun. From late fall to early spring, seed in areas without frost.
- Because they are climbers, sweet peas require a structure they can wrap their tendrils around. They can scale walls, trellises, and even threads. No support is required for dwarf cultivars.
- The top 6 to 8 inches of soil should be cleared of weeds, and then it should be leveled and smoothed.
- The majority of plants do well in soils that have had organic matter added. Compost is a beautiful organic material that can be applied to your planting area whenever you like. It has the perfect pH level and nutrient balance. If compost is not available, topdress the soil with 1-2 inches of organic mulch after planting; this mulch will break down into compost over time. Following the growth season, a soil test will reveal what soil amendments are required.
- Plant seeds 2 inches deep and 3 inches apart, then cover with fine soil.
- Keep the soil uniformly moist and lightly compacted.
- Depending on the soil and weather, seedlings will appear in 10–14 days.
- When plants are 1 to 2 inches tall, thin them so that they may stand 6 inches apart.
How to Grow
- Keep weeds under control while the plants are growing. Weeds compete with plants for water, space, and nutrients, therefore keep them in check by frequently cultivating or by using a mulch to stop the germination of their seeds.
- Mulches also support stable soil temperatures and moisture retention. Shredded leaves used as an organic mulch for annual plants give the bed a more natural appearance and, as they decompose over time, enrich the soil. Mulches should never be placed on a plant’s stems to avoid potential decay.
- The growing season requires roughly 1 inch of rain every week for plants. To determine whether you need to add water, use a rain gauge. The optimum irrigation method is a drip or trickling system that releases water at low pressure directly into the soil. To reduce disease issues, water early in the day if you want to use overhead sprinklers so the foliage has time to dry before dusk. Maintain a moist but not saturated soil.
- Some protection from strong winds and intense sunlight may be required until plants grow established. Additionally essential is good airflow.
- Unless the plants exhibit nutrient deficiency, avoid fertilizing. Sweet peas may develop lush foliage instead of blossoms if you fertilize them excessively.
- To keep plants blossoming, remove spent flower heads.
- Observe for illnesses and pests. For advice on pest management measures that are suitable for your area, contact your cooperative extension service.
- In order to prevent disease problems the next year, remove plants that have been killed by frost in the fall.
Growing Tips
- Sweet pea vines are simple to grow and require minimal maintenance.
- Sweet peas give flower beds, trellises, and containers a lovely vintage feel in the cold springtime.
- Flowers with a strong scent are ideal for cutting.
- When it’s chilly outside, sweet peas thrive. They can withstand a minor frost.
Common Disease Problems
One of the most frequent issues when beginning plants from seed is damping off. The seedling appears healthy when it first emerges, but then it mysteriously begins to droop and die. A fungus that causes damping off is active when there is a lot of moisture present when the soil, air, and temperature are above 68 degrees F. This typically means that the soil is either too moist or heavily fertilized with nitrogen. Burpee advises keeping seedlings moist but not overwatering them, avoiding overfertilizing them, thinnng out seedlings to prevent overcrowding, ensuring the plants have good air circulation, and if you are planting in containers, washing them thoroughly in soapy water and rinsing them in a 10% bleach solution after use.
Downy Mildew is a fungus that eventually affects both sides of the leaves, causing pale gray areas on their undersides. Burpee Rotate crops with plants from a different family, according to advice. Avoid watering from above. Don’t overcrowd plants and make sure there is enough air movement. When plants are damp, stay away from them.
Fasciation: Fasciation is an unnatural flattening of stems that can give them the appearance of being joined. Often, distortion starts to appear in the plant’s base. It usually enters the plant through a wound and is brought on by a virus or bacteria. Burpee advises being extremely cautious when handling plants. Any plants that exhibit disease symptoms should be removed and destroyed.
When the weather is humid, a fungus illness known as powdery mildew develops on the tops of the leaves. The surface of the leaves seems to be white or grayish, and they may curl. Burpee advises giving the plants adequate air circulation through optimum spacing and pruning in order to prevent powdery mildew. For advice on fungicides, get in touch with local cooperative extension service.
Root Rots: Both mature roots and seedlings can develop root rots, which are caused by several pathogens. Burpee advises using crop rotation and avoiding planting closely related crops in the same location for an extended period of time. Grasp and throw away infested plants. Ensure that your soil drains well. For advice, get in touch with your local Cooperative Extension Service.
Rust: Several fungus infections that cause rust-colored patches on stalks and leaves. Burpee advises using crop rotation. Delete the diseased plants. For advice, get in touch with your local Cooperative Extension Service.
Common Pest and Cultural Problems
Aphids: These disease-transmitting sucking insects that feed on the undersides of leaves might be green, red, black, or peach in appearance. On the foliage, they deposit a sticky substance that draws ants. Burpee advises attracting or introducing aphid-eating predators like lady beetles and wasps into your garden. You can also use an insecticidal soap or a powerful spray to wash them away.
Leafminers: These insects make uneven serpentine lines by boring just under the leaf surface. The adults are tiny black and yellow flies, while the larvae are cylindrical yellow maggots. They typically damage the foliage rather than killing the plants. Burpee advises removing the damaged foliage. At the end of the season, make sure to clean up all the trash because sanitation is crucial.
Slugs: These pesky insects consume entire leaves or leave big holes in the vegetation. They feed at night, leaving a slime trail, and are especially problematic in wet weather. Burpee’s Advice Hand select, ideally at night. You can try using cornmeal or beer to lure the slugs into traps. Create a hole in the ground and fill it with a huge cup or bowl to serve as a beer trap. Make sure the object has steep sides so that the slugs can’t escape once they’ve finished. Beer should be poured into the bowl until it is about 3/4 full. The basin should be filled with drowned slugs by morning so that they may be emptied outside for the birds to consume. Put a spoonful or two of cornmeal in a jar and place it on its side close to the plants to create a cornmeal trap. Slugs are drawn to the smell, but since they are unable to digest it, it will kill them. Diatomaceous earth or even coffee grounds can be used to create a barrier around your plants. They are too big to crawl over these.
Spider mites: These minuscule insects, which resemble spiders, are approximately the size of a peppercorn. They can be yellow, brown, black, red, or black. They ingest plant liquids, sucking out chlorophyll and injecting poisons that leave the foliage with white spots. On the plant, webbing is frequently seen. They cause the leaf to stipple, dry, and become yellow. They proliferate swiftly and do best in dry environments. Burpee’s Advice Every other day, a strong spray can help control spider mites. Try using insecticidal soap or hot pepper wax. For advice on miticides, contact your local Cooperative Extension Service.
Thrips: Thrips are little, straw- or black-colored, needle-like insects. They attack flower petals, leaves, and stems while sucking plant liquids. The leaf surface of the plant will show stippling, discolored flecking, or silvering. Numerous illnesses can be transported from plant to plant by thrips. Burpee advises placing sheets of aluminum foil between plant rows to deter many thrips. After the first frost, remove all weeds from the bed and any debris. For information on pest control, contact your cooperative extension service.
FAQ
Can sweet pea seeds be sown indoors? Starting sweet peas indoors is not advised because they are difficult to transfer and are much easier to grow outside.
Why aren’t the flowers on my sweet pea plants blooming? Poor soil is preferred by sweet peas. They may develop into larger plants with plenty of leaves but few flowers if they are overfertilized. They also require at least six hours every day of direct sunlight.
Why did my summer sweet pea plants die off? Since sweet peas are cool-season blooms, the summer heat often causes them to wither away.
Can I cut sweet peas for a bouquet? Sweet peas really do make wonderful cut flowers! They smell delicious and honey-like.
Are sweet pea seeds or plants poisonous? Plants and seeds are indeed poisonous. Eat nothing from the plant, particularly the seeds.