Few flowers are as jaw-dropping as dahlias. With their geometric patterns and vibrant hues, these late-summer favorites effortlessly command attention. “It's hard not to fall for a large decorative dahlia with their layers upon layers of luxurious petals,” says Bailey Hale, founder and CEO of cut flower suppliers Farmer Bailey Inc. and Garden Club Plants.
Ree Drummond has been planting these showstoppers for decades, and years later, she’s still enamored with them. “I’m in love. Deep, deep love,” she said of her early dahlia garden. But aside from the aesthetic benefits, dahlias attract beneficial pollinators and improve soil health, according to Emily Nickerson, a horticulture and product experience lead at Eden Brothers.
With full sun, well-draining soil, and consistent moisture, these stunners typically peak from mid-summer through late fall. But with the right care, you can enjoy their spectacular show up until the first frost. By following a few simple tricks, you’ll be rewarded with gorgeous flowers for weeks longer than expected. Ready to extend their eye-catching display? Here’s how to keep your dahlias blooming even as the days get shorter.
Cut Back Spent Blooms
Deadheading faded flowers is one of the most effective ways to keep dahlias blooming for longer. “Removing spent blooms prevents the plant from putting energy into making seeds, freeing up nutrients to make more and more flowers,” Hale explains. For a clean cut, make your incision right above the node, which is where the leaves connect to the stem.
Prioritize Deep Watering
Dahlias thrive when they’re adequately hydrated, but they dislike sitting in soggy soil. To promote more blooms, Nickerson recommends deeply and consistently watering your flowers—but avoiding overly saturating them. When the soil starts drying out, aim for the root zone and focus on even moisture, so it doesn’t become waterlogged.
Adjust Your Fertilizing Routine
When the seasons shift from summer to fall, your dahlias’ fertilizing needs naturally change, too. Instead of sticking to the same fertilizing schedule, Nickerson recommends giving it a seasonal update. By late August to early September, hold off on applying nitrogen-based flower fertilizers, which will just force the plant to produce new growth that the upcoming temperature drop will destroy. Then, when the first frost hits, you should stop all fertilization.
Offer Structural Support
As you encourage your dahlias to bloom brighter and longer, all that growth can cause your plant to flop. To prevent this from happening, Nickerson suggests providing support with stakes, cages, or trellises. With a little reinforcement, you can help their flower heads remain upright and their stems stay intact.
Protect Against Cold Weather
To enjoy fresher-looking dahlias for longer, protect them from cold weather. If you spot an unexpected chill in the forecast, keep your flowers warm by covering them with a frost cloth or some lightweight fabric before nightfall and then remove them the following morning. Shielding your plants from an early cold snap will help you get more time with them.
Lilly Blomquist is the associate editor at The Pioneer Woman, where she writes lifestyle stories across a wide range of topics—including news, entertainment, holidays, food, and more.
