Wash your dahlia clump very well, especially near the crown where all the tubers come together. This is critical because you'll be making your cuts in this area.

The hardest part about dividing Dahlias is identifying the "eyes". These must be present in order for a section of tuber(s) to grow and flower.

I recommend that you place your clump in a shallow tray or container covered with moist peat or wood shavings. Keep it cool and dark. In a few weeks, the "eyes" should appear and you can make your cuts so that each tuber piece has at least one eye.

If you're after MORE plants or feel like it won't work, you can pot this clump shallowly in potting soil and start growing it under lights. In a few weeks, the eyes will sprouts called basal shoots that can actually be removed from the clump when just about 4" tall and rooted like a regular stem cutting. These small plants are then planted out after all danger of frost and can bloom the same summer! By the time these root, frost should have passed and you can chop up that original clump which should still have adequate "eyes" developing because taking a basal cutting actually encourages new shoots!

Best of luck!!

Riz

See this link it is really good:

http://www.dahlias.net/dahwebpg/Propagation/Propagation.htm#Propagation

That link is really good. Some dahlias produce tubers in a tight-knit clump that are nearly impossible to divide even for seasoned veterans. In those cases, you have two choices: dig and store as a clump, in vermiculite or wood shavings, not WET, just barely moist or you're inviting mold and rot for sure. Peat is found to have drying qualities, but some people use it successfully. Cut off as much green stem and roots as you can prior to storing.

Option 2: leave them in the ground well mulched with straw, leaves or evergreen boughs to protect against excess water/cold. In the latter case, you can dig it up in the spring and hopefully see where eyes are showing/shoots are formed and use a machete or big knife to divide the clump with very little precision needed. Just aim for a whole, firm tuber attached to each visible green shoot or raised, light-colored eye.

Let all cuts dry to the touch. Use of lysol spray or sulphur dust on cut edges isn't a bad idea no matter when you divide. Then you can go on to pot them up, or plant the tubers/quarter clumps/whatever you end up with after surgery... once the soil hits about 50 degrees. The kiss of death is cold, wet ground in Spring. Do not plant too early.

The biggest benefit of digging annually is avoiding overgrowth of clumps. It's much easier to deal with a few tubers produced annually vs a gnarly, old, half rotted mess that's been in the ground a few years. Plus it is said you get better blooms from single or smaller clumps of tubers- less competition from each tuber trying to get the nutrition out of the soil in that area. Makes sense to me.

Hope that helps.

Thanks for all your help!

That link is a good one - it is what I had referenced BEFORE I realized what a tuber-mess I had!

It was so bad that many of the tubers were deformed from being squeezed. I couldn't even get a screwdriver in there like some sites recommended!

So, I did divide. (Although it sounds now like I should have waited.) I think very few are salvageable (as I had to break a lot of the necks to get into the clump). The broken ones are tossed, I will toss the ones with no eyes. For the ones that are questionable I think I will plant half and store half, to give me the best odds.... (Although I am not hopeful, if any spares make it - I'll bring them to the spring plant swap!)

And I will try to divide more frequently. (I didn't know you had to this often! I thought you had to lift them once a year only if you were taking them in for the winter!!)

Thanks again for all your help!!!

ugg, mine are the same. Probably a 12x 14" mass that I've been trying to pry apart for hours. Eyes have already sprouted. They made beatiful, prolific blooms for months last summer/fall so can't think this huge clump was too unhealthy.