Expert: Long Island Gardener - 9/30/2006

Question
My zip is 02660.  I would like to know the procedure for removing and storing dahlia bulbs for the winter.

Answer
Wait for the first light frost to set down in your part of Massachusetts, which appears to be in Zone 7, same as me.

Cut the flower stalks down, leaving 3 inches above the ground.  Keep them all in the ground another 10 days or so.  Then use a pitchfork to gently loosen and then dig up the whole clump. You can't be too careful about this, Eadie.  You don't want to damage the tuber.  Be gentle.

Many people try to short-cut this exercise by yanking on the Dahlia stem.  

Don't you go and 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 the roots off with a scissors and let the clump dry.

You can store your tuber or try your hand at propagation.  This is the best thing going because you multiply plants you already have showned you can grow.

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.  Me, 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 the collection someplace dark and frost free. Store in a cool spot where temperatures don't go over 55 degrees F.  And wait for spring.