Garden Help Desk: Proper Storage Keeps Dahlia Tubers Ready for Spring Planting | News, sports, jobs

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Dahlia flowers come in many sizes, shapes and colors.

Courtesy Meredith Seaver, USU Extension

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Just like all dahlias in our area, these little dahlias will not survive the winter unless their tuberous roots are dug up and stored in a cool place where they will not freeze.

Courtesy Meredith Seaver, USU Extension

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The dahlia plants in this container garden were cut, overwintered in an insulated garage, and then set off in early summer for another season of bloom.

Courtesy Meredith Seaver, USU Extension

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I planted some dahlias for the first time last spring. I heard that if I wanted to plant them again next year, I could save them by digging out the bulbs before they freeze. I did that and put the blocks in a bucket in my laundry room but I’ve been too busy so far to take care of them. What should I do with them?

Dahlias grow from tuberous roots, which are a little different from bulbs, and you’ll handle them a little differently than bulbs. Hopefully you dig the stems and roots together because the roots will not produce new growth next year unless there is some stem still attached to them.

Gently shake the loose soil. You can rinse the blocks to remove any remaining soil, but it is important to let the blocks dry completely afterward. Many gardeners simply store tuber clumps without rinsing the soil. In either case, handle the mass carefully to avoid breaking the tops or damaging the skin of the tubers.

The tubers you save should be firm and light brown in color. Sunken, dark, soft or watery spots are signs of frost damage or disease.

You can divide the tubers before storing them or wait until spring. If your dahlia plants have only a few small tubers, you can keep the mass as is. If your dahlia plants are very vigorous and you have a large, crowded collection of beautiful, plump tubers, you should divide the collection. Use a clean, sharp knife for this job. Each tuber needs a piece of neck and some “eyes” (buds) otherwise it will not grow.

To store the tubers, you can distribute them in bins or boxes, place them in paper bags, or wrap them in newspaper or something else that provides a little air circulation and keeps the tubers from touching each other. Keep them in a cool, dark (but not freezing) place with good air circulation where moisture does not condense on them.

Check the tubers every month or so until planting time next spring and discard tubers that show signs of rot.

If dahlias are grown in a container, you can simply cut the stems back to about two to three inches and store the container in a cool place where the dahlias will remain dormant without freezing. If your dahlias are crowded in their pot, you can remove the root ball and separate some of the roots from their stems before replanting them.

My walnut tree is finally starting to drop its leaves. Can I put it in my garden? I’ve heard they can poison some plants, but I hate wasting all that organic material by sending it to the landfill. Is it better to put the leaves in my compost pile instead, or should I not use them at all?

You are unlikely to need to worry about this. Many gardeners are concerned about using leaves or wood chips from walnut trees because juglone, a compound naturally found in walnut trees, may inhibit the growth of other plants. Juglone’s effects have been demonstrated in laboratory research, but limited research “in the field” has been inconclusive. There does not appear to be clear evidence that juglone enters the soil and damages plants the way it does when applied to seedlings and young plants in a laboratory setting.

Fortunately for gardeners who need to clean fallen leaves from pecan trees, juglone decomposes within a few months due to microbial activity in compost piles or with simple exposure to the elements.

The leaflets of walnut leaves are large in size. You will compost more easily if you use the chipper or baler attachment on your mower to speed up the process. Once the composting process is complete, you can use this fertilizer the same way you would any other fertilizer.

The wood of walnut trees has a very low juglone content, so wood chips from walnut pruning can be safely used as a soil mulch in shrubs and flower beds. Just like chips from any other type of tree, they should not be mixed with soil.

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