March 6, 2013


Cut flower sweet peas are one of the most amazing flowers a gardener can ever experience, but they are not always the easiest to grow. Here is the story about how I raised long stemmed English sweet peas this year.

Last year I became obsessed with English Spencer Sweet Peas - so variety grown by true Sweet Pea enthusiasts in England and elsewhere, because of its characteristically large blossoms and long, long stems. Once the most popular cut flower in America ( in 1900), today, the sweet pea is still somewhat scarce, which just means that you will need to grow your own from seed, as this is another one of those annuals that you will not find in garden centers as seedlings ( and, you shouldn't, as the best plants are those grown from seed in your own garden). As many of you know, I sort of became a little too obsessed last year, even having a party to celebrate their mass blooming in June. Since many of you have shared an interest in trying to grow Spencer Sweet Peas yourselves, here is a photo-heavy step-by-step post on how I grow mine. Enjoy!

Sweet Pea enthusiasts use a new type of pot called a root trainer, and the name Rootrainer is also a brand. Google it, if you think you can invest in a set ( they are not cheap, but they are reusable). Some people use toilet paper tubes ( silly, really, and not horticulturally sound as they will decay long before you can transplant your seedlings). Root trainers allow seedlings to produce long roots, essential with sweet peas, especially since you will be pinching the seedlings to encourage even more roots in the first few weeks of growth. Of course you can use most any pot, yogurt containers - what ever you feel comfortable with, but look for deeper containers rather than shallow ones. Sweet peas dislike root disturbance, so Root Trainers allow you to unfold the pot, and slide the root ball out with a minimum of disturbance. With regular pots, you will just need to carefully tap and slide out the root ball.

Varieties are important, and I encourage you to seek out the Spencer variety if you are large flowers and long stems. You certainly can use American seed strains if you wish, but I assure you that the flowers will be smaller, and the stems shorts. Heirloom varieties exist, and they are often more fragrant, but the true Spencer strain forms have the newest varieties - those grown for exhibition in England, and I believe the largest foliage and flowers. Grown side-by-side with American Royal sweet peas, you will instantly see the difference. I order mine from Owl's Acre in England, but there are many sources in the UK and even from California (although, I honestly would just look at the Sweet Pea Society website in England, and check out their source list - these growers grow two crops a year, to ensure the freshest seed - one crop in the UK, and then one crop in New Zealand during their summer). I cannot stress the importance of getting the finest seed you can get.

I sow seed starting in late February, but also as late as mid March ( I am late this year). I sow two seed per cell, and then I pull one out and toss it, keeping the strongest seedling to grow on. At the second leaf stage ( above) I pinch the growing tip out ( it's what the professional exhibitors do). This encourages more roots, which is so important for sweet peas as the vines will grow 8 to 10 feet tall, and by mid summer, the hot temperatures will require plants to have deep and strong roots.

Starting in mid March, I start bringing plants outdoors to harden them off. All peas love cold weather, and many can handle light frosts. At first, I bring the flats of root trainers back into the greenhouse, but by late March, I leave them outside all night, only protecting them if snow threatens.

In the third week of March, I start setting out the strongest seedlings into a prepared bed. I don't add manure from the chicken and duck coops into the soil because one must control the nitrogen level, but I do add bone meal and a drench of tomato fertilizer ( 2.5.5), along with compost. I use cloches to protect plants from heavy early frosts.

These pinched seedlings show how the root trainers work. Yes, I forgot to pull out the extra seedling here, but at this stage, I can still snip off or pinch out the two weaker stems.
 In the rear, you can see the bamboo cordon system I use - 8 foot bamboo canes, attached to a wire which extends between two snow fence poles. This creates a very sturdy structure which you will need once the vines mature and bloom.

Seedlings after being set out, watered and fertilized. One plant per cane. I know, I know, a little crazy, but wait till you see the results.  This is exactly the same way exhibition sweet peas are grown in England. If you think this is silly, I can say that the foliage on the sweet pea plants grown this way is four times larger than those on conventionally grown vines. The goal at this point? Strong roots, so I pinch plants again just after planting. Don't worry, you will be surprised at how pinching early will stimulate plants to produce side shoots which will be even larger and more sturdy than the original growing point.  For some reason, side shoots are massive  and more aggressive than those on un-pinched plants.

After pinching, strong shoots will emerge from the base of the seedling. At this point, around May 15th, you will need to start tying vines to the canes ( they will not grasp on by themselves).

I use vinyl tape for tying sweet peas, as it does not damage the stem, it stretches and ties easily. I know, it is not environmentally sound, but it just means that I must collect the pieces at the end of the season. Many UK growers use this material for staking tomatoes and sweet peas. Its' very soft, and will not harm the plant.

By June 1st, vines will start to grow incredibly quickly, almost 3 inches a day. Have twine or tape ready, for they will need to be tied every other day or so. I tie at each internode. It's a pleasant task, relaxing after a long day at work, just listening to the robins, and making little bows.  I've tried twine, rope, twistems, but this soft plastic ribbon is the best, as sweet pea stems are winged, and tear easily with even thick twine. If you want to be more organic, you may want to try cutting fabric or cloth ribbon. I think the trick here is a flat material and not a round one, which will cut into the stem.

Tendrils emerge at the end of each leaflet, and they will need to be cut off, or this will happen. They will grasp onto bud and nearby leaves, encircling them and causing havoc. Carry a pair of little scissors, and snip all tendrils off.

Flower stems need to grow tall and long, and tendrils will cause trouble. Again, it is a strangely pleasant task, snipping off tendrils every day after work in the evening. Sometimes, tending to plants with snips and ties, can be like therapy.

By mid june, flower buds will appear, and extend long and tall. If the first set yellows and falls off, don't dispair, but keep an eye out for virus' and aphids. If you are lucky, soon will will have amazing long stems of fragrant sweet peas.

Some of these stems are 18 inches long, with blossoms nearly 2-3 inches in diameter. Properly grown sweet peas are amazing and impressive, probobly because we rarely ever see them, even at florists. Once you grow your own sweet peas, you will understand their charm and respect why they were so popular a hundred years ago when people cared about such things.

The color palette with Spencer Sweet Peas is unmatched. coral, cerise, periwinkle - some of the purest  colors seen outside of Valentines Day or the My Little Pony aisle at Target. I can say that, because I know :). The Yummiest colors of any flower, indeed. So go get your sweet peas on!

Awesome pictures to follow:


  1. I saw some already in full bloom peaking over a fence a few blocks away from me. I swear next year I am going to start mine in fall when I should. This year I'll just once again live vicariously through you.

  2. hopflower9:55 AM

    Oh,yes. My favourites. Mine are up about two and one half feet already. Large leaves, deep green, and many, many vines. I start mine in October.

    It won't be long!

  3. Anonymous5:15 PM

    Well would you believe it Matt, Owl Acre Sweet Pea suppliers are located in Spalding, Lincolnshire, England and guess where I live? So Close I can almost smell them. Well blow me away. Thanks to your post my sweet pea dreams will come true!

    Thank-you :)

  4. Matt,

    The organized and linear presentation of your sweet peas is gorgeous! Perhaps I'm getting too big for my britches since this is the first year I'm growing them...but how many inches away from one another are your plants/canes? I'd like to try this method for growing them.

    Thank you in advance!

  5. These really are stunning. Too bad that at my family's place in Michigan the summers seem to just be too hot for them.

  6. I've really enjoyed your sweet pea series (not just because it immediately conjures their scent). Can't wait to try some of your suggestions in the garden this summer!

  7. Well done post, thank you!

    I live minutes away from Enchanting Sweetpeas in Sebastopol, CA. Website ~ http://enchantingsweetpeas.com/pagesnew/sweetpea_individual.html Glenys Johnson is the owner/grower of Spencer sweetpeas. She imports varieties from England and has been in business for about 25 years. Once a year she opens up her sweetpea garden to the public and it's magnificent!

  8. This year I followed your advice up to the plantation in beds... I had no idea thoug that I had to keep only one sucker per plant. The results are much better than the last years but next year I'll do better. Thank you for sharing

  9. Using the cordon method, how many flowers per plant? And how long are the stems?

    Helyn Bolanis

  10. Thanks for an inspiring and beautiful post. Now, Help please!! It's April 13 in Long Island, NY, and we had a late and cold arrival of spring. Is it too late to plant my sweet peas? I guess I am months behind....will mulching with straw help? Thank you so much!

    1. IT's not too late, they'll just bloom later. Especially since you are on Long Island, the cooler weather ensures that your season should be longer. I've sown outside as late as mid-May here in Worcester, MA. Good luck!

  11. So one plant per cane and only one stem going up?

    1. Exactly - One stem per cane is the proper way to train sweet peas for exhibition. You'll just have to make a choice, if you require the longest stems and largest flowers, then limit one stem per cane - but it's difficult, as so many stems will emerge and one will be challenged to keep at least a few extras growing (I am not that much of a purist!), but if I was exhibiting or wanted the largest, most perfect incredible sweet peas, then I would limit growth to one stem per cordon. I grow a few rows in this manner every year just because they make incredible cut flowers and look quite different than those plants which I allow to form 2 or 3 stems.

  12. I have a similar question. If there is one plant per bamboo pole, does this include the side shoots? Do you gather the main shoot and side shoots and tie all together to one pole? Or, do you select a few of the strongest shoot from one plant and tie those to the pole?
    Thanks. Great article.

    1. The 'proper method is to limit one stem per cane. I do cheat however and allow two stems or occasionally 3 stems but it's very clear when one sees a plant limited to a single stem, as the foliage will be much larger and the floral stems longer. If you are trying to raise the largest blossoms and the longest stems, then try limiting to a single stem - exhibitors in Sweet Pea exhibitions raise them this way.

  13. Anonymous1:16 PM

    Mine look like they will start to bloom any day now! I was inspired by my sister & her husband's sweet peas in Oregon 30 years ago!
    I have been obsessed with them ever since.
    I am going to Dublin in later July for the sweet pea show there.

  14. Hey Matt, I hope you still check this. I'm interested in growing my sweet peas in the cordon method, but I'm a bit confused on how to layer them once they reach the top of the supports. What do you do with yours? I'm a visual person, do you have any photos of this part of plant management? Thanks!!

    1. I rarely untie them and drop them since I grow mine outdoors and it gets too warm here for them to continue after mid-July, but when I did do it I cut the green vinyl tape that I use to tie them with to the canes, and drop them all before I retie them. It takes a little organzing to lay them all out away from the canes, but it can extend the season. I'll look for photos and maybe do another post. THanks!

  15. Anonymous5:21 PM

    I purchased some root trainers and am wondering about the large drainage opening...How do you keep the soil from all falling out of the bottom?
    Bobbi C.

    1. Hi Bobbi. The root trainers I use don't have holes in the bottom, they drain through the sides. I do have some deep cell trays however that are 6 inches deep and while the holes are about 3/4 inch, the soil, if one uses Pro Mix doesnt feed through.

  16. Thank you for all the great info, Matt. I am in zone 5 and am wondering how early I can expect my sweet peas to bloom if I plant them now. I realize this will be variable. You mentioned planting yours mid February and getting blossoms as soon as June. What zone are you? Do you have any advice an hour bloom time in zone 5?

  17. Thanks for all the info. I am located in zone 5 and am wondering how early I can expect flowers if I plant my seeds now (3/15). You said that you plant yours in mid February and see blossoms as soon as June. What zone are you in? Do you have an info on bloom timea in zones 5?


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