Growing Dahlias: How and Why to Pinch Your Plants
To pinch or not to pinch? If that is your question, we say pinch! Though dahlias will grow just fine on their own, one little pinch will give you a stronger, bushier plant with more flowers. This holds true whether you are growing border dahlias, dinnerplates or decoratives.
When to Do It. The best time to pinch a dahlia is when it’s between 12″ and 16″ tall and has at least 4 sets of leaves on the center stalk. At this point the plant is growing rapidly and will quickly recover from being pinched.
How to Do It. Locate the upper-most sprout on the main stem and remove it with your fingers or a pair of scissors. Take care not to damage the stem or nearby leaves. In the photo above, you would pinch out the narrow, upright bud that’s located between the top two leaves.
One week after being pinched.
Why to Do It. Removing the plant’s terminal bud will stimulate lateral buds (lower on the stem) to develop into new stems. Where the sprout was removed, the plant will generate two shoots rather than one.
Above: 3 weeks after being pinched.
Pinching temporarily redirects the plant’s energy toward producing stems and leaves rather than buds. It will take an extra week or two to get flowers, but it’s definitely worth the wait. Your plants will be stronger, fuller and easier to manage. Plus, all those additional growth points will give you many more flowers. A benefit you’ll still be enjoying in October.
During the summer and early fall, when your plants are in full bloom, cutting flowers for bouquets has the same beneficial effect as pinching. It keeps the plants bushy and stimulates more bud production. Removing spent flowers — or deadheading — does the same thing and also helps the plants look their best.