Growing Concerns 608: Dahlia tubers, garlic clove sprout

Late Winter!

Dahlias need warmth but garlic needs cool to grow


Dear Janet,

I haven't planted dahlias before.  Am I better off ordering tubers by mail or are there garden centers locally that will have a good selection early enough to plant late this spring? Any other advice?


Dear C.R.,

Where you buy depends on if you want growing plants or dormant tubers, and whether you need a particular color and type of flower.

For potted dahlias, shop locally. I bought some fine potted dahlias late last spring from a local garden center. At other times I've bought them from growers at the farmer's markets.

If you plan to place the dahlias as filler near perennials like oriental poppy or lupine that wane after their spring bloom, tubers are best. It's less intrusive to slit the soil and insert a tuber alongside that perennial, than to plant a potted dahlia there. Local garden centers may carry both potted dahlias and tubers, but it's tubers-only if you order by mail.

Do you want a specific dahlia variety? To find it takes shopping around. Chances are you'll find it only by mail.

 There are so many dahlia varieties that no one seller can carry them all. Each of your local garden centers may carry a half dozen. It's unlikely that you'll find a particular one of the thousands of existing dahlia varieties in such a small pool. Your chances improve if you include mail order sources in the equation.

There are generalist and specialist mail order firms. Generalists are like a garden center, offering a few types each of a hundred species, from Anemone to Zantedeschia. A specialist may list just one species but a hundred or more varieties. So shop dahlia specialists to find a particular color and shape of bloom. 

To find those specialists, use your computer or a library's Internet connection. Go to the Dahlia Society at to use their "Big List" of links to dahlia growers.

If you order by mail, specify a late May ship date unless you have the time and inclination to start the tubers in pots indoors. That's because dahlias do not like cold soil and perform poorly all season if planted before the ground is 60 degrees or more. Those temperatures don't occur in Michigan gardens until early June.


Dear Janet,

The garlic on my kitchen counter has started to sprout. Can I pull the cloves apart and plant them and grow my own garlic? And what is the best way to do this?


Dear L.,

Some garlic varieties grow well here. So plant that sprout. It's worth a try, even if it turns out to be a type that doesn't like Michigan winters, or can't get what it needs here to produce hefty cloves.

Full sun and well drained soil are all it takes, but get it planted as soon as you can break into the soil. Garlic needs cold prior to its blooming season to produce side bulbs. If it goes straight to bloom, it may put all of its gusto into one flowering bulb that will be a culinary hull by harvest time..

Short report

Gardening under oak trees

J.D. wonders if it's possible to garden under oaks. Yes! In fact, given a choice of tree to garden under, I'd pick white oak. They tend to be high branched, leaf out late in spring and keep some leaves right through winter. That means plants at their feet get more light during the growing season and more protection from winter extremes.

Oak roots tend to be widely spaced and relatively deep. I can dig without hurting the tree's roots or putting my garden plants into close competition with the tree.


I enjoy answering questions you mail to me or post on my school's website. However, don't expect much help from me if you pose a "stumper" such as: Why, on a murky March day as I yearn for color, must landscapes be dominated by bright blue- and orange tarp-covered items? What happened to earth tone tarps?


Green thumbs up

to the stalwart snowdrops and witchhazel already in bloom, and the snow crocus just joining them.


Green thumbs down

to the lack of foresight that caused me to plant my late winter bloomers away off in a corner of the yard I can hardly see from my winter perches.

 Originally published 3/5/05