Dahlias: Single Tubers vs Tuber Clumps

Which Produces the Best Dahlia Plant?

Spring planted dahlias can be bought as single tubers or as tuber clumps. Which is better? Turns out both grow nicely.

Small dahlia growers usually sell individual tubers. A fall harvested root clump can be cut into a number of single tubers, producing more dahlias for the grower to sell. Each tuber must have an eye, as this is what sprouts and grows into a new plant. If a clump has several eyes, a knowledgeable trimmer can harvest several eyed tubers. However, this takes time and skill.

Dahlia farmers with large growing fields produce greater numbers of plants. These dahlias are typically harvested, washed and sold uncut. Most of these larger operation growers find it more efficient to sell clumps rather than trimming out individual tubers. Because clumps aren't carefully hand trimmed, they aren't as pretty. They look like what they are - gnarly roots.

Clumps typically have some shriveled and/or loosely attached tubers along with the viable one(s). This is normal. While not necessary, trimming off the surplus tubers can make the clump easier to plant. Here's how to do that: Preparing Dahlia Clumps for Planting.

One Tuber = Sprout Lunchbox

In spring, before a dahlia has developed the root network required to support the actively growing plant, the sprouting eye needs fuel for development. That’s where the attached tuber comes in. The tuber is the lunchbox that stores carried-over-from-last-season carbohydrates to jump start the new season’s growth.

A single tuber is required to supply the fuel for the growing sprouts; more are fine, but not necessary.

This is why healthy dahlia plants will grow from a single small tuber with one eye. Or from a clump with one to several well attached tubers and several eyes.

Basket of washed dahlia tubers

We offer full clumps because with an intact collar there are typically more eyes.

Single trimmed dahlia tubers

More eyes translates to . . .

  • multiple stalks (trim to the strongest) for fuller plants  
  • a safety net if one eye or sprout gets damaged

This basket of freshly dug and washed dahlia roots is ready to cut or store as is for winter. ->

The tubers below are from a small market grower. Each has a single eye.

Tuber Size & Shape

Note the difference in the dahlia tuber size and shape. Varieties and individual plant vary. This is normal. Similar size variances occur with clumps, some large and some smaller.

Small tubers or clumps are not a cause for concern. An intact collar (where the sprouting eyes are located) and one tuber to support the plant as it begins to grow, is all that's needed. 

One long time commercial dahlia grower we know says he's happy with tubers the size of AA batteries for his plants, i.e. small.

Eye Visibility

Dahlia eyes are much more visible on freshly dug roots in the fall than on stored roots come spring. While in storage the dahlias lose some moisture causing the eyes to shrink and pull back into the stems. The eyes are still there, but they're harder, sometime darn near impossible, to see. Plant the dahlias; the eyes will rehydrate and grow. 

Our dahlias are held in cold storage to reduce premature growth of eyes, to avoid damage in transit. Learn more about : Dahlia Tuber Eyes here.