How to Top and Disbud Your Dahlias for Beautiful Blooms

Dahlias are one of the superstars of the summer garden. They provide stunning visual interest with their colorful blooms, and they’re beautiful cut flowers.

However, in order for your dahlias to thrive and produce the best blooms, you’ll need to do a bit of maintenance. Topping and disbudding are two essential—and easy!—gardening tasks that will help your dahlias create larger, higher-quality blossoms. To help you get started, we spoke with dahlia experts about how you can properly groom these beautiful flowers—along with a few common mistakes you should always avoid.

What Is It?

Topping and disbudding are each very important. However, they’re very different methods, and should be performed at different times during the growing season. 

Topping

Topping is also called pinching or pinching out, and it’s performed early in the season when the flower is about 12 to 14 inches tall.

“Topping removes the central growth tip of the plant,” says dahlia breeder Kristine Albrecht. This is important because the central growth tip produces hormones that suppress branching in the axillary buds lower down in the plant. Removing the growth tip reduces the hormones, allowing the plant to produce additional lateral branches, making it bushier and more productive.

Disbudding

Disbudding is done later in the season, when the plants are actively producing buds.

“On a typical dahlia stem, you’ll see one central bud, flanked by two smaller, lateral buds,” says horticulturist Kate Walz. “Disbudding is the practice of removing the smaller side buds, which enables the plant to put all its energy into the central flower.”

Benefits of Topping

Topping your dahlias early in the growing season can make a big difference in the plant’s future appearance.

“Removing this central stem encourages the plant to branch out, creating more flowering stems,” says Walz. “Although this process will delay the blooming time slightly, overall, it will give the plant better structure—and ultimately more flowers.”

Benefits of Disbudding

“Disbudding doesn’t affect the shape or growth pattern of the plant,” says Albrecht. However, this method still plays an important role.

Dahlia plants typically produce one main bud at each bud location, along with two secondary buds. “The main bud is further along in the blooming process and will bloom first. If that bloom is cut from the plant, the secondary buds will never bloom,” she adds. “They’re too far behind in the maturity cycle.”

By removing the two secondary buds early on, the dahlia puts all of its energy into the main bud, making it a bigger, more beautiful bloom. That isn’t the only benefit of disbudding. It can also help preserve the plant’s energy, which it can put into tuber production. 

Another key benefit: “[Disbudding] gets growers to routinely look closely at their plants. When disbudding, growers often see pest or nutrient issues that they wouldn’t have seen [otherwise,]” adds Albrecht.

How to Do It 

Topping and disbudding are very easy processes that won’t take up too much of your time. Here’s everything you need to know to successfully perform both methods.

Topping

Topping is as simple as pinching off the tiny tip of the plant’s main stem.

The best time to top is when young plants have four to five leaf junctions and are 12 to 14 inches high. “At that age, the plants don’t have a hollow stem,” says Albrecht. “The growth bud is easily removed by snapping it off with your fingers. The wound heals in a few days.”

Disbudding

When dahlias set buds, each bud location has one central bud and two smaller lateral buds.

Disbudding is the process of removing those lateral buds. You can do this with a clean pair of pruners, or you can bend the small buds with your fingers so they easily break off. “Proper disbudding involves snapping off the buds, not pinching them,” says Albrecht. 

Common Mistakes

Despite everyone’s best efforts, it’s not unusual to make mistakes when topping or disbudding dahlias. Here are a few that you should avoid making.

Topping Multiple Times

Topping is a singular moment in the plant’s growth that will last for its lifetime.

“The most common mistake people make is [topping] it more than once,” says Albrecht. Once the original terminal bud has been removed, the plant will branch for the rest of its life cycle. “People new to dahlias often top a plant and then continue to top it as the plant produces more lateral branches,” she warns. “That will reduce the plant’s ability to produce copious blooms.”

Disbudding Too Late

“Once the buds start to open, the energy from the plant to make the flowers has already been spent,” says Walz. Be sure to disbud when the lateral buds are still quite small. Disbudding too late can leave a large scar.

Topping Too Early

It’s important not to pinch the plant too low, even if it’s early in the season.

“Removing too much of the plant (leaving only one to two sets of leaves) weakens [it] and delays its growth as it tries to recover,” says Walz. The sweet spot for topping is just above the third or fourth set of leaves. 

Topping Too Late

“[Another] common mistake is that growers wait too long before removing the growth bud,” says Albrecht. “Growers who wait until the plant is 3 to 4 feet high must use tools to remove the growth bud. By then, the stem is hollow, and will collect water that could rot the tubers—or provide a habitat for earwigs.”

Using Your Fingernails

When disbudding, remember to use pruners—or just carefully snap the buds. “Some growers use their fingernails to pinch off the wing buds,” says Albrecht. “This gets the plant’s juices on the fingers, and when they pinch on the next plant, they could spread viruses or diseases.”

Using Dirty Tools

“For both pinching and disbudding, it’s crucial to ensure you have clean, sharp pruners,” says Walz. “Dirty or dull tools can introduce disease or cause ragged wounds that don’t heal well—and they may even compromise the entire plant.”