How to Pinch Dahlias the Right Way (and When to Do It for More Growth)

With their beautiful, big blooms, growing dahlias undoubtedly add the wow factor to your yard. Pinching is a common part of dahlia care, involving removing the top portion of the plant to encourage branching and bushier growth. 

We asked the experts when to pinch dahlias and how to help you make the most of their first-class flowers. 

What Is Pinching?

Pinching is a type of plant pruning that involves removing the new tender growth at the end of a stem. Doing this forces the plant to grow a couple of new stems from the leaf node underneath your cutting. This encourages the plant to become fuller, producing more stems and flowers.

Want more gardening tips? Sign up for our free gardening newsletter for our best growing tips, troubleshooting hacks, and more!

When to Pinch Dahlias

“Assuming that we are talking about tall cutting garden dahlia varietals, you should pinch the plant back when it gets to about 12 inches tall (2-4 weeks after planting),” Nicole Dillon, Master Gardener and the owner of Breemar Flower Farm, says. 

At this stage, before the plant fully matures or begins flowering, it should have at least four sets of leaves on the center stalk. Waiting until then to do the first pinch will help your dahlia recover quickly.

How to Pinch Dahlias

1. Sanitize your snips to reduce the risk of spreading disease. 
2. Cut off the growing tip from a single stem or central stem above a set of leaves. This first pinch is referred to as “stopping”. June Nash, the General Secretary of the National Dahlia Society, explains that this will cause stems and buds to grow from the axils of the lower leaves, and you will have more flowers in the first flush. Axils are the angles formed where leaves or branches connect to a stem and where buds develop.
3. The new stems that grow will terminate in three buds, and these will benefit from a second pinch, referred to as “disbudding”. “If you take out the two side buds and the two buds in the next axils lower down the stem, you will get a bigger flower and a stronger stem,” Nash says. 
4. Repeat debudding as the plant continues to set flowers.
5. Leave a few blooms on towards the end of the season, allowing them to go to seed. “Dahlia seeds are hybrids, and plants from them hardly ever resemble the parent plant, but it’s good fun, and they create plants for nothing,” Nash says.

Dahlia Care Tips

• Enrich the soil: Dahlias appreciate rich, fertile soil with good drainage. Amending the soil with humus (decayed organic matter) before planting is beneficial.
• Pest prevention promotes the best blooms: Monitor daily and manually remove slugs and Japanese beetles. Organic aphid infestation control is possible via neem oil or insecticidal soap.
• Watch out for weeds: Fast-growing interlopers compete with dahlias for nutrients, water and space. Mulching and hand-pulling control weeds while preserving the beneficial soil microbiome better than if you introduce chemical killers.
• Stake for support: Tall dahlia species are susceptible to slumping and storm and wind damage. Staking or using tomato cages for support helps to keep your plants upright.
• Dig up tubers: Heavy frosts kill dahlias. Digging up and storing dahlia tubers for replanting the next spring saves you from having to buy more plants.
• Don’t waste the pinched tips: Dillon suggests creating more dahlia plants by rooting your pinched tip. Alternatively, add it to your compost pile to make organic matter for future planting.