Dahlias top the list of our favorite summer flowers, and we have a couple of tricks for growing them successfully at home.
Stake dahlias at planting time
Most dahlias grow to 3-5 feet tall and need support to prevent the bloom stalks from breaking. We have a super-easy staking technique we use in the Sunset Test Garden—all you need are bamboo stakes and some garden twine. Watch the video below and you'll see me set up a trellis like a giant spider web.
Pinch back for more blooms
Another key to growing dahlias is pinching back the plant a few times during the growing season. Technically, you need to pinch back the terminal bud to promote lateral branching. We usually pinch dahlias once or twice in spring to encourage the plants to grow bushier and produce more flowers on the laterals. In the video below, I'll show you just where to pinch back.
Here's how the Sunset Test Garden dahlia bed grew in by mid-summer—more flowers than we knew what do to with! You can barely see the trellising we set up at planting time.