How to Grow Sweet Peas in the South

**Note- This post is geared towards the home gardener growing sweetpeas in a backyard type of setting.

Sweet peas- once you get a whiff, you’ll never be without them in your garden again. Sweet peas in the South aren’t super common. However with the rise of cut flower gardens over the past few years, they are getting more popular. But it’s not all sweet smelling purfume. Growing them in the South requires a few tricks that are different from the common sweet pea knowledge you’ll find on the interwebs.

Let’s start from the beginning: Seeding

Sweet pea seeds look like brown or occasionally white dried peas. They are in the legume family but all parts of the plant are poisonous. Smells only on these! ( They’ve always been fine to grow around my animals- I think you have to ingest quite a quantity to be dangerous but always a helpful thing to know about any plant. )

A lot of sweet pea seed is bred in England and New Zealand. You can import the seeds in small quantities fairly easily or you can buy it from some new breeders that are popping up in the US. Ardelia Farm in Vermont and Sweet Pea Gardens in California are two sources I’ve used with good success. Fresh high quality seed is the most important factor in getting good germination. You’ll see recommendations for soaking or nicking seeds but it’s not necessary. Store your seeds in the freezer once you received them until you are ready to plant.

There are early and late flowering sweet peas. Look for varieties that say they are a spencer type as these are the late types and are better for growing outside. The early types are bred for greenhouse growing and are not as cold tolerant. Some of my favorites are Nimbus, Oban Bay, Mollie Rilstone, Charlie’s Angel, and Strawberry Fields.

It’s best to start sweet pea seeds in containers and plant out a transplant versus direct sowing. Sweet pea seed is not cheap (around 50 cents a seed) and I’ve often seen seed rot or get eaten by rodents when direct seeded. You’ll want to wait until the temps are just right before sowing- daytime temps of average 60’s and nights at 45-55 degrees. So don’t fret if you haven’t started yet, you’ve got plenty of time.

Sow into containers around 2” deep and around 1” in diameter. You don’t need a super big or deep container. NOW—- any northern grower who just read that is saying- “You’re wrong!” Here's one of the instances that Southern growing is different: in the South, we get a small window where we get the correct temps to sow sweet peas. Sow too early and you get leggy plants due to the heat, too late and they don’t get established well before the cold. So the goal is to get the seed started in a controlled environment and have it ready to plant within 3 weeks from sowing. Northern growers will plant into deep pots with lots of room for the transplants to develop as they grow in a very cold environment and then get planted in early spring. I’ve used the sow it and transplant it quickly method for years and it works really well in the South. Fall planting seedlings in the South will give the same slow growth and root development in the ground that Northern growers get in a pot.

Growing out and Planting your seedlings:

Once your seeds have sprouted, keep them in a cool place with bright light. Usually our temps towards the end of October are perfect. I don’t recommend starting sweet peas inside under grow lights because most houses are too warm. Sweet peas like it cool! This is counterintuitive to how most seeds are started but if you keep them too hot, they get too tall too fast and they fall over and break.

Once the seedlings are 4ish inches tall, they should be ready for transplant. You want to make sure they have at least once set of true leaves on them.

Plant into a well composted bed, preferably with the soil raked up to raise it a bit for good drainage. You don’t want to rot them out. Sweet peas are hungry little plants so make sure your bed is well amended with a good organic fertilizer and lots of compost. Space them 6-9” apart. 9” is preferable if you have the room because it will make it easier to harvest come Spring.

Keep the plants watered until established. During the winter, water if the soil becomes dry. Over the winter the plants will begin to branch out from the center and each branch will be around 8-12” long laying on the ground. This is fine for now— Don’t put up your trellis until late February/early March. When you see the plants start to turn upwards and try to climb, then it’s trellis time.

During the winter when it warms a little, 60+ degree days, you can apply a water soluble fertilizer such as fish emulsion.

Sweet peas are very cold hardy. They can take temps down to low 20’s before they need cover. I cover mine once or twice a season and I’m usually playing it safe rather than sorry.

Trellising and Harvesting:

I use a netting called Hortanova Tenax netting. It comes in different widths and the 6’ wide is really good for sweet peas. The vines will grow pretty tall but I never put up a trellis taller than 8’ because I know I couldn’t reach any higher and I don’t want to get out a ladder. Once they start getting tall, you just have to cut harder to control the growth. Use a t-post about every 6’ if growing in a row. Stretch your netting very tight and secure it with zip ties to the t-posts. You can also make a tripod style trellis from bamboo canes or other tough supports. To encourage the sweet peas to grow upwards and not out, I take bailing twine and run it laterally about 3” off the ground and use it to scoop the sweet peas up. Then I add a row about every 6” for the first 2 feet, then 1’ apart after that. I usually stop around 4-5’ because if you add too much after that, it gets hard to harvest.

Sweet peas will begin to grow stems with buds in April usually. They will look droopy at first but will straighten out as they grow. The correct harvest stage is when 2/3 of the buds on a the stem are open. You can cut at the base of the flowering stem or you can cut down the vine if you need a longer stem. To ensure you are getting fresh stems, cut 2-3X per week. The more you cut, the more they flower.

There is a phenomenon called bud blast that can affect sweet peas in the spring. Sweet peas are very sensitive to climate/environmental changes. For example, if the temperatures swing dramatically or we get a ton of rain, it can cause the buds to turn brown and drop off. The buds will reform, usually takes about 2 weeks. I see this happen usually every year. It’s just a fact of growing sweet peas in a climate that fluctuates a lot during the Spring.

Aphids can also be common on sweet pea flowers and they can even show up before flowering begins. So keep an eye out for them. Shower them off with a spray of water or use a insecticidal soap.

Sweet peas have a vase life of about 5 days on average. If it’s a cool spring, then they may last longer in the vase. If it’s hot, then maybe only 3-4 days. Mine usually keep flowering until late May/early June. Keep watering them and harvesting to keep the blooms coming!

But most of all — Enjoy your Sweet Peas! I don’t know of a better flower that is such a treat for the senses- smell, touch, sight!

**Sweet pea transplants still available in the online store.

Spring Blooming Containers

Don’t have enough room for a cutting garden? Try a cutting container instead. I’ve come up with several good combinations for beautiful spring containers. Definitely plant more than one so you can have one to cut from and one to display on your porch or patio.

Each combo requires a pot that’s at least 12-15” deep and 18-24” in diameter — really the bigger the better but you can use multiple smaller pots. Fill with a good quality potting mix— whatever is available at your local garden center, preferably an organic mix if possible. Potting mixes are designed for good drainage so I recommend those over a straight compost or mixing your own (unless you really know your soil). Most potting mixes already contain fertilizer but if it doesn’t, try a granular fertilizer that has equal parts of nitrogen, potassium and phosphorus (also known as a balanced complete fertilizer).

Our plants come in 6 or 8 plug strips so buying one combo will actually give you enough to plant 2-3 pots. Make one for display, one for cutting and one to give away!

After filling with organic potting mix, space your seedlings 6'“ apart in the pot. Water thoroughly after planting and make sure the plants stay watered well for the first few weeks while they are establishing. During the winter, water when they are dry. If your pots sit in an uncovered area, monitor to make sure they don’t stay constantly wet. We have wet winters in Upstate South Carolina and you are more likely to loose plants to rot than to cold. Moist soil will also help prevent your plants from cold damage but too much water will cause rot. So moist soil not drenched soil!

Alright— ready for our combos?

Combo 1

Anemones and Ranunculus- this will be a long blooming combination with the anemones starting to bloom in March and the ranunculus beginning in April. They’ll bloom together until mid May. Any combination of colors you like. My choices would be hot pink ranunculus and blue anemones or salmon ranunculus and maroon anemones. With this combo, you’ll want to keep cutting off the spent blooms— this will produce more lovely flowers. Feel free to cut blooms for your vase from this container!

Combo 2

Sweet pea tripod trellis- One pack of sweet peas is perfect for planting on a tripod style trellis. My choice of sweet peas would be the blue mix. Plant around the outside edge of the container about 6” or so apart depending on pot size (just space evenly). You can wait until early March before putting up your tripod poles. You’ll want one pole for each plant. Sweetpeas can get tall so think 6-7’ for your poles (Bamboo canes work well). Tie them together at the top. You can also use a flat or ornate style trellis.

Combo 3

Campanula, Blue Anemones, and Magenta Dianthus- Plant 2 of each variety in the pot grouping like plants together. If your pot is not round and you are planting front to back, place the campanula in the back because it’s the tallest and then the dianthus in front of the campanula and the anemone in the very front.

Combo 4

Snapdragons, Tropical Mix Ranunculus, and Coral Dianthus- Plant 2 of each variety in the pot grouping like plants together. Snaps in the back and mix the ranunculus and dianthus in the mid section and front.

Combo 5

Peach Foxglove, Lemon or Cream Ranunculus, and Maroon Anemones- Foxgloves are the tallest here so in the back or center and mix the ranunculus and anemones in front or circling around the foxgloves. 2-3 of each variety depending on pot size.

Combo 6

Lavender Foxglove, Purple Sweetpea Mix, and Pink or Maroon Anemones- You’ll need a flat trellis in the back of your pot - plant sweet peas 6” apart and then plant the foxglove in front of those then the anemones in the very front of the pot— a square pot would work well for this one. All of these 3 require 6” spacing so plant how ever many your pot will hold with the recommended spacing.

Combo 7

Yarrow, Coral Dianthus, and Snapdragons- This pot has some later blooming varieties and will start late April and go through May. All 3 things are pretty tall so I would suggest planting evenly spaced (6”) and position this pot in the back of a grouping of pots.

Combo 8

Salmon Ranunculus, Peach Foxglove, and Pink/peach Sweetpea mix- The ranunculus will bloom first in this mix so position them towards the middle or front. The sweetpeas will need a trellis to climb so plant them towards the back. The foxglove would look nice off to one side or maybe framing the sweetpea trellis.

Combo 9

Magenta Dianthus, Lavender Ranunculus, and Campanula- The tall spires of campanula will make a good tall focal point for the back of the container. Then mix ranunculus and dianthus in the middle and front regions of the container.

Combo 10

Pink Anemones, Snapdragons, and White/Blush Sweetpea- Place a trellis in the back for the sweetpeas, then add the snaps in front of the sweetpeas. The anemones will fit in the front of the container.

Feeling inspired? Take a look through our Fall Plant shop and pick out a winning combo that will produce beautiful blooms all spring! Or contact us with your color needs and we’ll suggest some beautiful combinations sure to make your porch or patio dazzle!