Expert: Long Island Gardener - 9/17/2006

Question
My zip 13601 When should I dig up my glads and adalhia for the winter

Answer
Dave, Upstate New York is probably too cold to leave these plants in the ground.  Certainly it would be risky eveb if you were to mulch them carefully and provide superb drainage.  You are right to want to lift these.

For your Dahlias, wait for the first light frost, then cut the stalks down leaving about 3 inches left above the ground.  Keep them in the ground another 10 days or so, and then use a pitchfork to gently loosen and then dig up the whole clump.

You can't be too careful about this, Dave.  You don't want to damage the tuber.  Be gentle.  Many people try to short-cut this task by yanking on the stem.  Don't make that mistake - you'll destroy the tuber and turn your Dahlia into a compost pile addition.

Lift the tuber, and then use a garden hose to clean the clump.  Cut off with a scissors the roots and let dry the clump dry.

At this point you can store your tuber or try your hand at propagation.

Cut the tuber with sharp scissors or a knife.  Carefully divide clumps in half by splitting with pruning shears.  You'll find a handy illustration of this procedure at the swan Island Dahlias website (www.dahlias.com/index.asp?PageAction=Custom&ID=2#13). Each tuber should have an eye at the point where the crown is slightly enlarged.  You'll notice the eyes are located mainly near your Dahlia stem.  Prepare a homemade disinfectant by mixing a cup of Bleach to 3 gallons of water and let your tubers soak there for 15 minutes to 1/2 hour, then place them on newspapers and let them all dry.  Keep them out of the sun.

Some people overwinter their tubers in plastic bags with vermiculite.  I prefer to keep them in peat moss in the basement, in an open plastic container, and mist them every few weeks with some water.  Keep them someplace dark and frost free. Store in a cool place where temperatures rarely hit 55 degrees.

Now let's discuss your Gladiolus.

Use the same pitchfork and dig your Gladiolus bulbs up when growth the leaves turn brown, before a real freeze renders the garden surface hard as a rock. Make your cut right above the bulbs.  Toss out any diseased corms.  Let the bulbs sit a month. Then wash them well, getting rid of the dried up roots. Leave husks on.  You can find some good drawings of this at Illinois Coooperative Extension(www.urbanext.uiuc.edu/bulbs/bulbbasics.html).

This is a very tricky autumn responsibility, Dave.  For me, this would not be the first year I did not dig my Dahlias and Gladiolus up due to waiting too long.  Last year, our first hard freeze seemed to come out of nowhere and the ground was solid rock after that.  To my amazement, half my Dahlias and Glads survived - thanks to good luck and excellent drainage.

When you put them back in the ground next spring, don't forget to sign up for water.

Any more questions?  I'm here.