Should I Trellis Sweet Peas? (Tips For Success)

Small garden tasks such as trellising plants, laying down mulch, or pinching back certain flowers are easy to push to the back burner until it’s well into the season. However, if you’re growing flowers such as sweet peas for their long stems for cut flowers, then making time to trellis them right from the start is the best way to get the flowers you want. 

To help your sweet pea plants reach their maximum height and produce long, straight stems, trellising is a must. As natural climbers, sweet peas will grow up any structure they can wrap their tendrils around. Without a trellis, sweet peas will grab onto neighboring plants, potentially smothering them and tangling up their stems. 

No matter what your budget or gardening space looks like, there is a way of trellising sweet peas that will suit you. I’ll include tips and trellis ideas to help you find the method that works best for you.

Can sweet peas grow without a trellis?

Sweet peas can be grown without a trellis if you opt to grow compact varieties or if you don’t mind your trailing varieties sprawling across your garden bed. The vines will tangle, and the flowering stems will curve as they reach for the sun, but that only matters if you’re hoping for long, straight stems for cutting.

If you plant varieties that reach 4-6 feet tall, the vines will creep across the ground, looking for anything to grab onto. You will probably see the sweet pea vines grab onto neighboring plants, the tendrils wrapping around stems and leaves in an attempt to grow upward. 

It might not be a big deal if the neighboring plant is sturdy enough. However, if you’re growing tender plants like other flowers or greens, you probably won’t get the performance you expect as the two plants compete for space and sunlight. 

A better option for growing sweet peas without a trellis is to choose compact varieties that form a mound of flowers instead of sprawling vines. These varieties will perform well without support and won’t get a stranglehold on the plant next to it. 

Alternatively, you can try growing your sweet peas in a hanging basket. 

Growing sweet peas in hanging baskets

If you don’t have a trellis for your sweet peas, you can try an alternative to give their vines somewhere to explore via a hanging basket. 

Trailing sweet pea varieties will spill over the edges of the baskets, their flowering vines cascading toward the ground. You might still see the vines grabbing onto each other, but they’ll have enough space in the air that each vine will still thrive. 

Compact or bush varieties of sweet peas will also grow well in hanging baskets, their shorter vines hanging over the edge of the pot. 

For more information specific to hanging baskets, read this article next: 7 Simple Steps To Grow Sweet Peas In Hanging Baskets.

How tall should a sweet pea trellis be?

The taller the sweet pea variety, the taller the trellis should be. For example, for a variety that grows 4-5 feet tall, your trellis should be 4-6 feet tall. This height will support most of the plant and provide a little extra for those vines that reach maximum potential.

When buying stakes or posts to support your trellis, remember that you’ll need to sink them into the ground at least a foot. If you need a six-foot-tall frame, buy a stake or T-post at least seven feet tall to anchor it well into the ground. 

You can also try attaching your trellis to an exterior wall or porch column to minimize what you need to buy for your sweet peas. This year, I used a staple gun to attach chicken wire to a column in our entryway. The sweet peas climbed up easily, and I didn’t have to buy additional posts or stakes to support the chicken wire. 

How do you attach sweet peas to a trellis?

As sweet peas grow, they cleverly throw out little side shoots called tendrils. These tendrils will reach out and wrap themselves around whatever they find, anchoring the plant as it grows.

In the beginning, you can help your sweet peas get a firm start up their support by tying the young vines to the bottom of the trellis or by weaving a few inches of each vine through the mesh, but once the plants get going, they won’t need much help from you. 

How to tie in sweet peas

As your sweet pea seedlings reach 5-6 inches tall, they will benefit from being guided up the support you have given them. Garden twine or flexible ties will work well, but if you don’t have either, you can also weave the vines into the trellis, though this works better when they’re a bit taller. 

To tie the vines in, hold the sweet pea stem up to the trellis, then gently tie it onto the support with a straightforward knot using twine or a twist if you’re using ties. Don’t try to connect each branch, just get the main stem stabilized, and the plant will take over from there. 

You might break some tendrils, but the plant will quickly recover. If you accidentally break a stem, leave the plant in the ground. Depending on where the branch broke, the plant will respond by sending out a new stem at a leaf node, which will carry on as before. 

If you break the stem at ground level or a few inches without any leaves on it, then that vine is done for, sorry to say. The other plants will quickly fill in that space. 

By supporting your plants in their early days, you’ll avoid any plants getting crowded away from the trellis and spreading across the ground instead. 

As your plants get bigger, they will send out more tendrils to help support themselves. As the plants get heavy with blooms, check to see if any branches are getting crowded and unable to reach their tendrils close enough to the trellis to grab on. 

If that’s the case, a quick pass-through with some twine to secure those stems will help to keep the plants growing tall. 

When to add supports for sweet peas

The best time to install the posts, trellis, or other supports for your sweet peas is before or at the same time as the seeds or seedlings. Placing the supports before any significant root development avoids disturbing the sweet peas’ root system or breaking stems as you sink the posts or install the trellis.

What kind of trellis do sweet peas need?

The best trellis for sweet peas has mesh, twine, or stakes spaced close enough together that the vine’s tendrils can grab on when the plant or young. It also needs to be tall enough to support the tallest varieties and wide enough to accommodate the branching nature of sweet pea vines. 

Beyond that, as long as the trellis is strong and well anchored into the ground, they will grow up just about anything. 

Here are some trellis ideas you can try, some of which you may already have in your collection and one that is a statement piece worth investing in for your flower garden. 

Chicken wire

Chicken wire can be a great way of supporting sweet peas, allowing them to spread outwards and upwards, creating an almost screen-like effect. As your plants grow, you will have a blanket of glorious, sweetly scented blooms, bringing pollinators buzzing into your garden. 

You can attach chicken wire to T-posts at each end or attach it to an exterior wall. Sweet pea tendrils are small enough to fit between the wire and the wall while keeping the stems and leaves free to grow up the open side. 

Bamboo stakes

Bamboo is a cheap, natural, and sustainable product to use in your garden. Simple bamboo supports can be made by sinking individual canes into the ground and tying them together at the top to form a teepee or pyramid shape. 

To encourage your sweet peas to climb their bamboo stakes, wrap twine around them up to the top. The twine’s texture will make it easier for their little tendrils to grab hold of the slippery sticks. 

Hortanova or trellis netting

Hortanova netting works similarly to chicken wire. This netting is what most professional flower farmers use as it’s strong and versatile for many garden uses. You can pick up something similar at many garden centers, such as this trellis netting.

Use two tall T-posts anchored a foot into the ground to attach each end of the netting. Your sweet peas will cover it in no time!

Obelisk

If you have a healthy budget for your garden and want to add something stunning, you can invest in an obelisk. In addition to coming in a wide range of colors, sizes, and designs, an obelisk’s cylindrical base structure makes it stable enough that they don’t need to be dug so deeply into the ground. 

These ornamental structures have the additional benefit of being reusable year after year and are highly decorative in the garden. You could even pair your sweet peas with another climber, such as clematis, which looks impressive on an obelisk. 

Learn more about sweet peas

Your sweet peas will soon be climbing up the trellis support you provide for it, but there are a few other steps you can take to make sure you have the best sweet peas season yet. Here are a few ideas to get you started: