Gardening Experts Says This Common Dahlia Mistake Can Hurt Blooms

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If you’re dreaming of a garden filled with bright, colorful blooms, dahlias should be on your radar. But gardening pros say there’s a common dahlia-growing mistake that you need to avoid if you want these flowers to thrive.

But first, why do gardeners love dahlias so much? “They are the lowest-maintenance, highest production plants you can grow, giving 30 buckets of cut flowers per square meter within just a few weeks of planting,” says Sarah Raven, a gardening expert and author of A Year Full of Pots. “They also come in all shapes and sizes now, with ones that last well in a vase, ones that are stacked full of pollen and nectar — so good for butterflies and bees.” And the best part? They bloom later in the year “when there’s so much less around to love, look at and enjoy.”

Having a healthy garden takes a little more than sun and water. It also requires planting your flowers, vegetables, and fruits near other plants that can benefit them. For instance, some of the best companion plants for tomatoes are basil and garlic, since these plants repel pests. It’s no different with dahlias. They need to be planted near plants that can help them thrive — and they should definitely be kept away from ones that can impede their growth or attract pests.

The dahlia-growing mistake pros want you to avoid

There’s one major mistake some people make when planting dahlias that can impact the flower’s growth. Planting them near “anything that draws in slugs and snails like bean plants,” Raven says. She also recommends keeping them away from delicate plants that grow slowly — think geraniums. “They look good at the same time as dahlias but will be choked by the stinking, vigorous growth of the dahlia family and don’t stand a chance,” she explains.

She also notes that if you’re planting “whopper” dahlias, which can grow quite large, avoid placing them next to smaller plants such as Cosmos “Sonata” or “Sensation” series or zinnias “as they will again be overcome.” However, if you’re not going with the whopper variety, Cosmos and zinnias can be a great to grow next to dahlias.

If you’re looking for more companion plants, Raven suggests “bold, strong growers like the grains, amaranths and sunflowers, which work aesthetically and feed the birds as their seed ripens. The birds then eat the caterpillars, aphids, slugs and snails and keep the place healthy and clean. It’s a win-win.”

neirfy – Getty Images (neirfy – Getty Images)

Raven also says it’s a good idea to plant spore formers, such as gladioli, next to your dahlias. “Dahlias create undulating round shapes, and you want some vertical spikes to make a great design.”

And for next year, remember: “Plant the tubers inside, frost-free in mid-spring, don’t plant them just straight in the ground. Keep them in a cool, light, frost-free place until they’ve grown to a decent size (6-8 inches or so) before planting when the frosts are over out into the garden. Their juicy, soft shoots won’t get devoured by slugs and snails — a huge issue here with dahlias in a cold, wet spring.”