When and How to Pinch Out Dahlias for More Flowers

Pinching out is one of the most transformative techniques in dahlia growing. A single action at the right moment converts a plant that would produce one or two flowers on a tall single stem into a compact, multi-branched specimen capable of producing dozens of flowers across a long season. Yet many growers skip it either through uncertainty about when to do it or reluctance to remove healthy growth. Here is everything you need to know.

What Pinching Out Achieves

Left unpinched, a dahlia produces one dominant growing tip that grows vertically, produces a single flower, and then the plant's energy gradually diffuses into side shoots — but this happens slowly and the season is already partially over. When you remove the growing tip early, you eliminate the apical dominance hormone that suppresses lateral buds. All the dormant buds at each leaf node below the pinch point activate simultaneously, producing four, six, or eight side shoots depending on how many nodes the plant had at the time of pinching. Each of those shoots will produce its own flower — and then branch again when its flower is deadheaded.

When to Pinch — The Right Timing

Pinch out dahlias when the main stem has developed three to four clear pairs of leaves — typically when the plant is around 30–40 cm tall. At this height there are enough nodes below to generate a good structure of side shoots, but the plant is still at an early enough stage that the delay to flowering is minimal. Too early (one or two pairs of leaves) and there is not enough plant below to produce a good branching structure. Too late (five or more pairs) and you are removing a significant amount of developed growth for less benefit.

How to Pinch Out

Using your thumb and forefinger — or clean, sharp scissors — remove the growing tip back to just above the top pair of leaves. The growing tip is the soft, pale central shoot between the topmost pair of developed leaves. You should see two symmetrical bud points emerge from the axils of the topmost pair of leaves within a few days of pinching. Pinching by hand is usually clean enough for healthy plants; use scissors if the stems are tough or if you are working among plants where hygiene matters (avoid spreading disease between plants on your fingers).

Second Pinching for Even More Branches

Some dahlia growers pinch twice — once at the primary stage and then again when the resulting side shoots have themselves developed two to three pairs of leaves. This produces an even more branched and bushy structure and is well suited to border dahlias where a wide, floriferous display is the goal. However, each successive pinch delays flowering by another two to three weeks, so in short-season climates one pinch may be all the season allows.

Varieties That Benefit Most

Medium and tall varieties benefit most from pinching: decorative, cactus, semi-cactus, ball, and pompon types all respond well. Compact bedding dahlia varieties — particularly those sold in plug trays for summer bedding — are typically already bred to branch freely and may not require pinching at all. Check the variety description or observe whether the plant is already branching naturally before deciding whether to pinch.

Pinching Summary

• Pinch when the plant has 3–4 pairs of leaves (approximately 30–40 cm tall)
• Remove the central growing tip between the topmost leaf pair
• Side shoots from axil buds appear within days
• A second pinch is optional — it creates more branches but delays flowering further
• Bedding varieties bred to branch freely may not need pinching