Supporting your towering or bloom-heavy dahlias is crucial to prevent them from snapping or toppling over, particularly following a downpour or a powerful gust of wind. Establishing stakes either before or shortly after you’ve set them in the ground helps to avoid harming the tubers and ensures your dahlias stay propped up all through their growing cycle. Effective staking techniques encompass using posts with twine, robust tomato cages, individual stakes, or a horizontal netting system.
With their substantial, weighty flowers, dahlias are the prima donnas of the floral realm. After investing your efforts in planting and nurturing your dahlias, the last scenario you’d want is for a downpour or an inquisitive critter — chipmunks have been known to scale dahlia stems for a better view — to snap the stems or flatten them. Here’s how to stake your dahlias effectively to keep them looking their best.
Dahlias feature hollow stems, which makes them susceptible to damage in high winds or heavy rain. The larger the bloom, the more prone it is to drooping. Smaller blossoms can usually manage on even the longest stems, but the larger and giant dahlias, with flowers reaching eight to ten inches across, become quite heavy and are more likely to sag after a rainshower. Dinnerplate dahlias, with their colossal 12-inch diameter flowers and larger, are especially in need of support.
Staking your dahlias also keeps them from encroaching on walkways, enabling you to pass by without having to navigate through foliage and stems, and it prevents them from shading other plants. These stunning plants make a far more impressive display when kept upright rather than allowed to sprawl untidily across the garden. Moreover, if you’re cultivating taller varieties that can reach up to six feet, proper support will allow you to appreciate their full, towering splendor.
Although dahlias excel as the “thriller” in a container arrangement, taller ones require staking to stop the plants from listing to one side or, if the blooms become waterlogged, causing the entire pot to tip over. Providing support for potted dahlias keeps your containers neat and stable.
Many dahlia types grow to three feet or higher, and that’s around the point where staking becomes advantageous. However, shorter bedding types and smaller varieties often can do without stakes, especially in sheltered spots. Medium-height dahlias with compact blossoms might not need support, but it’s wise to have some form of backup in place to prevent issues later in the summer when the plants are in full bloom.
The optimal time to stake dahlias depends on the type of support chosen. For individual stakes per plant, it’s best to place them before planting to avert piercing the tubers. Support that doesn’t need to be close to the plants can be added later, once they’ve begun to grow.
The main thing is to have your support system ready before it’s desperately needed. If you’ve ever tried to jam wire tomato cages over plants that should have been staked weeks before (yet you forgot or just didn’t get around to it), you’ll know it’s much easier — and better for the plants — to have the stakes ready when the plants are young.
However you opt to stake your dahlias, make sure the materials you use are robust enough to bear their weight and keep them rigid in the wind. Tomato or wire cages offer a one-time solution, but for other methods, you’ll need to add fresh layers of twine or other materials a few times over the summer as the plants continue to grow.
For dahlias planted in rows, using posts and twine is a commonly adopted method due to its affordability, speed, and reliability. You’ll need some sort of fencing posts, typically T-posts or other metal posts, a suitable driving tool, and twine.
If you have a nearby farm supply store, consider purchasing a large roll of twine intended for baling hay. This will provide enough material for years of dahlia staking and other garden tasks, and it’s much more cost-effective than buying jute or twine in smaller quantities. The natural color of the twine blends well with the foliage, mulch, and flowers. Keep the entire roll in a bucket, pulling from the center, and carry the bucket with you as you work.
The number of posts you need will depend on the length of your row. Place two metal posts at each end and several more down each side of the bed, about 15 to 20 feet apart. Wooden or bamboo stakes should be set closer together.
Secure the posts or stakes firmly. Begin by tying the twine around 12 to 15 inches above the ground on a corner post, then stretch it to each post in sequence, wrapping around each one and moving on. Keep the twine taut but not so much that you bend the posts. Secure it at the starting post. Repeat the process about 10 inches higher as needed throughout the season. Some gardeners prefer to weave the twine in a crisscross pattern for additional support. If you use quick-release knots, you can reuse the twine for several seasons.
Large tomato cages are suitable for individual dahlia plants if you can anchor them securely into the ground. Galvanized or green vinyl-coated cages are both suitable options. For the larger dahlia varieties, go for the most heavy-duty cages available; they’ll last longer and be better equipped to support a five-foot-tall dahlia.
You’ll need one tomato cage per plant. If you have many dahlias, the cost and storage of the cages during the off-season might become a concern.
Plant your dahlia tubers as you normally would. Once there’s about 1 to 2 inches of growth, position the tomato cage so the sprout is right in the center. Push the cage’s metal ends deep into the ground, making sure to wait for the dahlias to emerge since they don’t always sprout where expected.
Many gardeners prefer to feature dahlias as solitary plants, allowing them to take center stage in a flower bed or large container. Single bamboo stakes, wooden tomato sticks, or even pruned tree branches can all work well (as can single metal posts). You’ll still need to tie the plant to the stake using twine at intervals, similar to the row method described above.
Insert the stake or post into the ground before planting the tubers or transplants. Plant the dahlias so that the sprouting eye is about a hand’s width from the stake. As the plants grow, secure them to the stake starting at about 12 to 15 inches from the ground. Adjust and retie them every 10 to 12 inches as they continue to grow.
As a general rule, a 4- to 5-foot-tall dahlia requires about three ties. The top foot of the plant should be fine without additional support.
Another support option is to use horizontal netting secured with posts. This netting, sold as trellis or cut flower netting, features 4- or 6-inch square holes for the plants to grow through. While this method is quick to install, separating the plants from the netting come autumn can be a bit of a task.
Hammer sturdy metal posts at the ends of the rows and at intervals down the sides. Once the dahlias have grown a few inches tall, put up the netting. It’s nearly impossible to install once they’ve grown taller and need to be individually threaded through the holes. Pull the netting tight between the posts and fix it to each post with plastic ties or twine.
Certainly, you can get creative and use anything from homemade, sculptural supports to old copper pipes with a lovely patina from a scrapyard. The crucial aspect is to have the netting in place before the plants grow large and to ensure that the posts are strong enough for the job.
