Growing Sweet Peas

How to Plant, Grow, and Care for Sweet Pea Flowers

By Catherine Boeckmann
Sweet Peas by Moravska/Shutterstock
Moravska/Shutterstock

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Few annual flowers have the lasting appeal and bucolic beauty of sweet peas. Twining lazily around a rustic trellis, they seem the very antithesis of our busy lives. With their seductive fragrance, sweet peas make great flowers for gardens and bouquets. See our Sweet Pea Growing Guide for information on how to plant and care for sweet peas!

About Sweet Peas

The sweet pea—Lathyrus odoratus—is an annual flower that is at home in a cutting garden, border garden, woodland, or twining on a trellis or an arch. The flowers are now available in a huge range of colors, from pearly white through ice cream pastels to ritzy magentas and inky purples.

Their dainty winged blossoms are matched only by their honey and orange blossom perfume. The combination of the delightful scent and the ability to produce so many blooms for the house over a long period of cutting has ensured their popularity.  

Early sowing is one of the secrets to growing sweet peas! Despite their delicate look, sweet peas are quite hardy. In Zone 7 or colder, plant them in very late winter or early spring as soon as the soil is dry enough to work. (Do not wait to sow until last frost.) 

The first sweet peas were introduced to Britain in 1699 when a Sicilian monk, Francis Cupani, sent seeds of this highly fragrant annual to Dr Robert Uvedale, a teacher from Enfield, Middlesex. They became hugely popular in North America, both as garden plants and cut flowers. By the late 1800s, California’s growers (including W. Atlee Burpee) shipped trainloads of sweet peas all over the country and developed many further varieties.

Some folks say that growing sweet peas is akin to making a pie crust. Some people have the knack, others don’t. This plant grows from large, easy-to-handle, pea-like seeds. Still, they’re a bit tricky because they are slow to germinate. It’s worth experimenting with different seeds each year. 

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Planting

When to Plant Sweet Peas

  • In most locations where frosts occur, sweet peas should be planted in very late winter or early spring as soon as the soil is dry enough to work. (Do not wait to sow until last frost.)
  • If you garden in mild winter climates (Zones 8, 9, or 10), plant sweet peas in the late fall (November) so they can develop and bloom in late winter and early spring. To get the best display, dig a trench and fill it with well-rotted manure or compost 6 weeks before you sow the seeds. Sweet peas are greedy plants and need a good boost of nutrient rich matter to thrive.

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Image: Easy-to-handle sweet pea seeds.

Sowing Sweet Peas Indoors

  • In the coldest parts of the country, get a jump on the season by starting sweet peas indoors in a seed tray. Sow in seed starting containers in early spring about 6 to 7 weeks before the last frost date, then plant out as soon as soil can be worked; sweet peas can handle light frosts.
  • Soaking the seeds overnight first softens the outer coating and aids germination. 
  • Then plant the seeds about half an inch deep in individual modules in a seed tray, 2 seeds to a module is fine but no more as their long roots have a tendency to tangle.
  • Once they are showing their first pea-like leaves, gently scoop them out and put them into a larger pot to harden off. The advice I had from one of the most respected sweet pea growers was “to treat the seedlings how I would my husband: stick them in an unheated greenhouse, ignore them and they will thrive.”
  • As the soil can be worked, plant them outside.

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    Sowing Seeds in the Ground

    • Sweet peas are happiest with their heads in the sun and their roots deep in cool, moist soil. When possible, plant low-growing annuals in front of them to shade their roots.
    • Choose a well-drained site. Alkaline soil is best; sprinkle some powdered lime on the surface if your soil tends to be acidic.
    • Prepare a rich soil by mixing in generous amounts of compost or well-rotted manure to a depth of 2 feet. (Learn more about soil amendments and preparing soil for planting.)
    • Prior to planting, you’re going to want to dig a nice deep “compost” trench of about 4 inches in depth. 
    • After you dig the trench, make holes with a pencil, drop in the seeds, and press down on the soil to firm it and shut out any light.
    • Before planting, soak the seeds in water for 24 hours. Then nick the seeds with a nail file before planting to speed sprouting. You do not need to soak seeds in a temperate climate.

    Video: We’ll show you how to plant sweet peas in this video demonstration.

    Care

    How to Grow Sweet Peas

    • Once planted, germination can take 7 to 15 days, depending on the soil temperature.
    • As seedlings emerge and grow, gradually fill in the trench. Hoe more soil up to them.
    • Keep soil moist. Summer rain may be ample. If you put your finger into the soil bed to its first joint and the soil is dry: water them at the soil level and do so in the morning; sweet peas can suffer from bud drop.
    • If you use plenty of aged manure and compost when planting, you do not need to fertilize. If you do want to add nourishment, use high potash feeds, as nitrogen feeds encourage too much top growth.

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    Provide Supports

    • Sweet peas prefer cool days and nights and will start to fade when temperatures go above 65°F.
    • Except for the bush types, sweet peas are real climbers. Give them at least 6 feet of good support. Some varieties may climb to 9 or 10 feet. Other visually-pleasing supports are bamboo poles in a tee-pee style, a woven willow obelisk, or a trellis. If you don’t have a fence or trellis, provide brush or chicken wire or bushy, stubbly twigs that they can cling to.
    • Tie the first few stems in to the support to give the plants a good start and the rest will follow. When they get to 4-8 inches high pinch out the middle growing tip with your thumb and forefinger. This will lead to sturdier plants. 
    • When plants become established, mulch well to keep the soil cool and moist. If you mulch, you may not need to water your sweet peas unless the soil gets dry.
    • To encourage bushy growth, pinch off the tops when plants are 6 inches tall—not before or you’ll encourage premature side-shoot development.

    Picking Flowers

    • Pick the flowers for bouquets often and the plant will put energy into more blooms instead of going to seed. The more you pick the more they produce, right until the first frosts.
    • When the leaves start to lose their color let a few of the last flowers form seedpods. Dry them on a windowsill and then store in an envelope in a dry place to sow next year.

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    Pests/Diseases

    Recommended Varieties

    There are sweet pea varieties for every situation, from 8-foot-plus scramblers to dwarf bedding ones suitable for containers and borders without support. 

    • In their native Sicily, these ornamental peas have weak stems and an intense orange-jasmine-honey scent. Modern hybrids are stronger-stalked and have larger blooms.

    • At the same time, some of these modern varieties with larger flowers and contemporary hues lack the fragrance of the earlier sweet peas. Sweet pea ‘Cupani’, with it’s bi-colored flowers, maroon upper petals with violet “wings,” is still deservedly popular and is easy to grow.

    • The deliciously-scented ‘America’ is an heirloom, dating to 1896. Its petals unfurl to show stunning wavy red and white stripes.

    • Look for heirlooms like the ‘Old Spice’ collection from Sicily. This strain blooms in shades of white, cream, pink, lavender, and purple.

    • ‘April in Paris’ is a fragrant modern variety with large creamy-yellow blossoms and lilac shading.

    • While the common sweet pea is an annual, there is also a perennial unscented broad-leaved everlasting pea, Lathyrus latiflolius. These are clambering plants, which can reach up to 6 or 7 feet and hardy to zone 5; they are low maintenance plants that flower regularly year on year.

    Wit & Wisdom

    • The sweet pea is an essential member of a late-Victorian garden. Victorians loved sweet peas for their color diversity and fragrance.
    • Gather the flowers in the morning when the dew is still on them. This is when their scent is the sweetest.
    • Sweet peas are one of the April birth flowers.

    “The odor of the sweet pea is so offensive to flies that it will drive them out of a sick-room, though not in the slightest degree disagreeable to the patient.”
    –A tip from The 1899 Old Farmer’s Almanac

    Sweet Pea
    (Delicate Pleasures)
    “Here are sweet peas, on tip-toe for a flight:
    With wings of gentle flush o’er delicate white,
    And taper fingers catching at all things,
    To bind them all about with tiny rings.”
    –John Keats (1795–1821)

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    Reader Comments

    Leave a Comment

    Sweet pea growing

    Submitted by Poppy on March 17, 2021 - 8:03am

    We are having a party for my husband in mid August and I would like to grow sweet peas to fill the tent. When should I plant them for maximum flowering? Mine are usually more or less over by this time.
    Thank you.

    sweet peas

    The Editors's picture

    Submitted by The Editors on March 29, 2021 - 8:37pm

    I’m sorry to say that sweet peas wouldn’t fit this seasonality. They are planted in late winter or early spring and only bloom in cold temperatures, before summer heat knocks them out. We’d suggest looking for a heat-loving flower that naturally blooms in mid-August. There are many options: Zinnia, Asters, ornamental Sunflower, etc. Just look at the seed packets and # of growing days to back out your planting dates and we’d also suggest staggering your plantings to hit the right dates. Nature’s unpredictable!

    Planting tips

    Submitted by Eulalia Wickham on March 4, 2021 - 8:41pm

    I love to plant flowers and veggies. I have enjoyed and learned from reading your tips and instruciton. Thank you.

    Sweet Pea pods

    Submitted by Jan Sutherland on December 31, 2020 - 7:27pm

    I am a total gardening novice, so forgive my question - my sweet peas have pods on them and I have cut them off - are these to be used for next years crop? Do I leave them to dry out? Thankyou in advance, cheers, Jan

    Sweet peas dwarf buyout mix

    Submitted by Heather may on August 8, 2020 - 7:31pm

    I live In Darwin but I love sweet peas. I'm going to give it a go.

    Option to Miracle Gro

    Submitted by Susan Breedlove on April 1, 2020 - 12:03pm

    I do not purchase any products of Monsanto due to the devastating impact that company has had throughout the world especially with their product Roundup which continues to be on the market despite proven lawsuits. What do you recommend as an option to Miracle Gro?

    Cobalt blue sweet pea butterfly vine question

    Submitted by Kathy on October 3, 2019 - 10:23am

    Will my sweet pea vine bloom more flowers if I pinch off the pea stems as soon as I see them?

    Please don't cut open your seeds

    Submitted by Carena on July 16, 2019 - 6:03pm

    The seed doesn't need to be cut open, unless you want generally weaker plants. I germinate EVERY SEED I grow by putting a paper towel in a Tupperware container, soak the towel with miracle grow water, add the seeds, snap the lid on and then put in the sun. I put sweet pea seeds out this morning using the above method and a few of them have split open on their own already. I also use this method to weed out the slower growing "weaker" plants

    sweetpeas

    Submitted by peter torrie on July 15, 2019 - 1:50pm

    how can I stop 6ft.high sweetpeas growing to that height.can I just nip them off at 3ft

    Yes

    Submitted by Carena on July 16, 2019 - 6:10pm

    Cutting them at the preferred height will encourage the plant to grow more from the base, resulting in a bushier plant. However, it won't just stop growing where you cut it. You'll have to maintain the height by periodically trimming over-growth. As long as you leave the plant with a few leaves, and don't mangle it, cutting/trimming the plant is fine.

    Sweet pea plant

    Submitted by Glenise Heywood on May 22, 2019 - 1:52pm

    We live in the UK and grow sweet peas every year. At one spot in our sweet pea bed the plant always dies, the others are fine. Can you suggest any reason please.

    Sweet Pea Problem

    The Editors's picture

    Submitted by The Editors on May 22, 2019 - 4:50pm

    There must be an underlying issue with the spot. It could be a number of things…  Does water tend to pool there? Or are there roots or rocks in that spot that prevent the plants from rooting well enough to survive the heat of summer? Is the spot exposed to more—or less—sunlight than elsewhere? Does a pet like to use that spot to do his or her business? Consider what might set that spot apart from the rest of the bed, and also remember to amend the soil with compost or fertilizer every now and again.

    Sun if heat

    Submitted by Jane on March 26, 2019 - 10:27am

    We are in northern VA, but get a lot of heat during the day in the summer- which I understand sweet peas do not like. I am hoping to put ours in a container. Am I better off putting them where they will be in an area with afternoon shade? Last time we put nasturturiums in the sunny area they were supposed to like they refused to grow, seemed to wilt in the heat and sun.

    If you're willing to do the work

    Submitted by Carena on July 16, 2019 - 6:07pm

    If you want to move the plant daily then you might be able to baby the plant. Otherwise I would find a spot that meets most of the growing criteria and possibly get a small decorative fence or canopy that will shade the plant during the hottest parts of the day.

    Sweet peas

    Submitted by Tina on August 17, 2018 - 11:51am

    Hello,
    My sweet peas go like crazy here in PNW and I love them...my question is this...
    Should I plant the seeds that I have already gotten from several of my plants at the same time that the plants pods open and drop theirs naturally? I would like to have some growing on my garden arbor. It receives great morning sun up until about noon, then a nice shading from some trees and then dappled light from about 1 pm on to sunset. I have ground cover that I can move outta the way until the shoots are tall enough to reach the bottom of the arbor (about 4 inches above the soil). I'm looking to fill this spot for a June wedding in 2019. Some guidance please....thank you.

    when to plant

    The Editors's picture

    Submitted by The Editors on August 20, 2018 - 4:51pm

    If you have seen plants come up from the dropped seeds, then it sounds like a good idea. Alternatively, purchase some seeds and start them at the appropriate time.

    Newbie Gardener

    Submitted by Jisenia on July 20, 2018 - 12:42am

    Hello! Im so happy I came across your site. I live in Tampa, Fl not sure what zone I live in. From what your chart suggested I should start planting in late Jan, is that correct? I dont have alot of natural sunlight on my property. What would you recommend I do? Its mostly shady and the mostly sand not dirt. Im afraid I might not be successful when I do plant them. Any input would greatly be appreciated.

    starting out

    The Editors's picture

    Submitted by The Editors on August 20, 2018 - 4:53pm

    You will need sunshine as indicated above. Most plants need 6 to 8 hours of sunlight. If you get sunshine, you need proper soil. Here’s some information on that: https://www.almanac.com/content/preparing-soil-planting

    transplanting wild sweet peas

    Submitted by Mary on July 15, 2018 - 10:46am

    Hello. I live in Northern Michigan and we have sweet peas in the wild in ditches throughout our county (Montmorency). I stopped on a dirt road this morning and couldn't resist digging up a couple of plants from a ditch to plant along a fenceline in my garden area. My question is are there any special considerations to a successful transplant?

    Good luck!

    Submitted by Carena on July 16, 2019 - 6:15pm

    If you're able to keep it alive, rooting hormone (follow directions on bottle) before you transplant might be helpful. Keep the plant inside, in water and some miracle geo or other plant food and in a bright room until it's "calmed down" or not as stressed from being uprooted . Every wildflower I've tried to transplant in the past was unsuccessful.

    Sweet peas

    Submitted by edna on July 11, 2018 - 9:55am

    Im in Vermont - Zone 4.., can i grow sweet peas here? I love the smell.

    Sweet pean in VT?

    The Editors's picture

    Submitted by The Editors on July 13, 2018 - 1:40pm

    Assuming all else supports them—soil, sun, etc. See the guidance above.

    King tut sweet pea

    Submitted by Jessica Harrison on May 17, 2018 - 12:04am

    I just received my order of gorgeous blue king tut sweet peas on May 5th should i save them or would it be ok to go ahead and begin to germinate

    Sweet Peas for zone 10a

    Submitted by Thimy on April 23, 2018 - 12:41am

    There are some sweet peas small plants available online for now. Can I grow them here in Zone 10a in May?
    As I learn from you that in zone 10a we need to wait until Fall, just wonder if it would bloom in Summer if I grow it now. Thank you.

    Root Trainers Sweet Peas

    Submitted by jeff on April 12, 2018 - 7:40am

    I'm growing Sweet Peas in biodegradable root trainers, when planting out in final position would you remove from the root trainer or leave it in place ?
    Kind Regards

    Sweet Peas

    Submitted by Jennifer Colona on March 28, 2018 - 1:39am

    My husband gave me an 8 foot trellis for our anniversary last year and I have been trying to decide what to grow on it. I really don't want to plant another clematis. I am in Southern New Jersey, zone 7 and have full day sun in my garden. My soil is a little on the clay side but I've amended it and had success with peonies and roses. I love sweet peas and wonder if this could be something that could work in my garden?

    Growing Sweet Peas

    The Editors's picture

    Submitted by The Editors on April 2, 2018 - 3:00pm

    It sounds like you have almost everything you need for growing sweet peas, though you will probably want to mix some compost into your clayey soil to make it drain better. (Check out our page of soil types for more info.) If possible, do a pH test on your soil as well, as sweet peas like it a bit alkaline. They are slow to germinate, so you’ll want to start them fairly soon!

    how to care for sweetpeas before winter

    Submitted by lorraine stewart on September 27, 2017 - 12:50pm

    hi would i have to do anything to prepare my sweetpeas for winter

    Transplanted sweetpeas

    Submitted by Darrel on August 5, 2017 - 3:57pm

    Live in central Albert zone 3. Transplanted 8 inch plants bought from a local Greenhouse on June 10th at the bottom of a North to South chain link fence.Planted a row of potatoes in front of them on west side for root shade.Have had some hot days in the 30celceis range with cool nights ,used some ultra bloom.once a week, now have a fence full of color.

    sweet peas

    Submitted by Cynthia on July 13, 2017 - 10:43am

    My daughter is planning an Oct wedding and would like sweet peas in her bouquet--I have started some indoors, they have just germinated and the seedlings are a few inches tall. It is way too hot here in the Midwest in July for outdoor transplant. Can I keep them indoors near a sunny window till cooler weather in Sept? or can I continue to grow them indoors till they flower? Thankyou

    Pages

    Growing Sweet Peas

    Botanical Name Lathyrus odoratus
    Plant Type Flower
    Sun Exposure Full Sun
    Soil Type Loamy
    Soil pH Alkaline/Basic
    Bloom Time Summer, Fall
    Flower Color Blue, Pink, Purple, Red, White, Yellow
    Hardiness Zones
    Special Features

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