Thursday, September 22, 2011

Don't Dig Those Dahlias Till Foliage Dies Back

When an informal decorative dahlia
shows its center, it means it's closing down
its blooming season.
Once the days begin to shorten and the nights grow cold in the fall, your dahlias will reflect the end of the growing and blooming season with certain changes.

The flowers will lose their form and you'll see open or "blown" centers. Stems will weaken, and the flowers will begin to set seeds. All this is a signal that your dahlias are going into dormancy. When the first frost comes, it's all over.  But in temperate zones, frost may be late in coming, and it may be long rainy periods that signal the end of your dahlias. Whatever the case, don't get tidy-minded and dig them as soon as you see blown centers and failing stems. They need to enter dormancy for the tubers to be ready to dig.

If there's a chance the ground will freeze before you can get your dahlias dug, suggests dahlia expert Bill McClendon, don't succumb to the impulse to tidy up by removing the blackened foliage after frost. Leave it to protect the soil and tubers from freezing. Before digging your tubers, remove the stakes and any wires or other support materials. And check your labels. If you didn't label your dahlias in the summer, try to recall the variety names now while there may be a lingering remnant of bloom to jog your memory.

When you're ready to dig the plants, McClendon advises, cut away the top growth, leaving 4 to 6 inches of stem attached, so you'll have someplace to attach the label and a good way to handle the plant. With a garden fork or shovel, begin digging well away from the stems so you don't damage the outer ends of the tubers; remember that there will be much more tuber than what you planted last spring. Lift the tuber mass gently, being careful not to break the fragile necks on the tubers.

Clean your dahlia tuber before you store it.
With a spray attachment, hose away all the loose dirt from the tubers. Use a fairly forceful spray to clean the tubers well but not so much force that you damage the outer covering of the tubers. Let them air dry, and dry well if you are storing them undivided. You may want to keep them a little damp if you plan to divide them right away before storing them.

McClendon advises dividing the tubers immediately, but other growers suggest drying and storing the tubers intact and dividing them later. At Lynch Creek Farm, they're dug and stored intact but divided later. Both methods have advantages. If the tuber clumps are divided in the spring, it'll be easier to see the "eyes" where new growth begins. But if you have large numbers of dahlias and limited storage space, the divided tubers take up far less storage space.

By the way, once you've dug your dahlias, DO clear away all the leftover plant material to make sure no dead foliage picks up unwanted diseases. In upcoming blogs we'll discuss dividing the tubers and storage techniques.

1 comment:

kyredhead said...

After I have dug the dahlia and cleaned the tuber, what is the best way to store them?

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