It is raining today in the Adirondacks. I have been reading questions and answers from my writing idol Garrison Keillor. Oh, to be as clever and funny writing about dahlias as he is about corn and tomatoes.
This year has been one for patience. I receive a lot of photos, even some from my own garden. As usual, the Tacoma Trial Garden looks grand as it always does. In the East, the Mid-Atlantic Trial Garden is growing well, but the blooms have felt the heat. In my Falls Church VA patch I see photos of green and open-centered blooms that look like daisies. This is the month to remove spent blooms, cut back tall stalks so you can see the blooms, and groom the plants.
What is “grooming?” After we nipped off the terminal shoot early in the season, and even if with didn’t, the lateral shoots will grow from the axes of the stalk leaves. This creates a bushy plant that needs to be tied to a stake, so it does not bow to the wind. Eventually, a lot of blooms will form with short stems, and neighboring shoots. Unless you enjoy dahlias au natural, you may want to dis-bud and thin the plants.
Dahlia buds usually come in threes, with possibly two more just below. To dis-bud, remove all but the center bud at the top of the stem. Ideally do this early in the morning when the plant is refreshed.
Then thin the plant by starting with a bud and removing leafy side shoots (not leaves) down the stem and stalk, three-four pairs of leaves deep. This will create stems for cutting, and open up the top of the plant. If you feel more aggressive you can reduce the number of long, lateral branches. These two steps will yield larger blooms.
Some exhibition growers of large blooms will only allow only one or two branches to develop blooms. All other laterals are removed. That is relatively drastic, but it wins ribbons. If you are floriculturally blood thirsty, you can cut the plant back to 30 inches so that it can grow new shoots and blooms over the next month or two.
Use the "grooming" link below to see some diagrams to help understand these grooming concepts.
This year, because we are away, my dahlias are growing au natural. When we return to Virginia in October we will start a salvage operation. This approach usually yields good tubers.