Dahlias: Single Tubers vs Tuber Clumps

Which is More Likely to Grow into a Healthy Dahlia Plant?

Spring planted dahlias can be purchased as divisions/single tubers or as full tuber clumps; which is better?  After many seasons of testing, we can confirm that both grow just fine.

Small farm growers tend to sell individual tubers. An end-of-season harvested root clump can be cut to produce multiple single tubers and this translates into 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 3 to 5 eyes, a knowledgeable trimmer can often get that many individual tubers from the clump. However, this takes time, skill and patience.

Dahlia farmers with large growing fields have the space to produce more dahlia plants, each of which can be harvested for an uncut clump. These larger commercial growers usual prefer to sell full clumps rather than invest the time and money in trimming to individual tubers.

Full clumps typically have some small or shriveled tubers along with the viable ones. This is normal. While not necessary, trimming off the surplus tubers makes the clump easier to plant. Here's how to do that if you're so inclined: Preparing Dahlia Clumps for Planting.

Basket of washed dahlia tubers

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

More eyes translates to . . .

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

This avid home gardener's basket of washed, wildly irregular dahlia roots (right) is ready to pack away for winter storage.

The ready-to-plant tubers below were supplied by a small grower. Each is trimmed to include a single eye. Writing the name of the variety on the tuber is common practice and a helpful way to reduce the likelihood of mix-ups.

Single trimmed dahlia tubers

Tuber Size & Shape

Note the difference in the dahlia tuber size and shape due to variety and individual plant. This is normal and to be expected. It's helpful to keep in mind that these are roots; not pretty and highly varied.

Similar size variances occur with full clumps. Some dahlia varieties tend to produce huge clumps while others mature with clumps on the small side. Sweet Nathalie is an example of a dahlia that typically produces a small clump.

Small tubers or small clumps are not a cause for concern. As long as there is an intact collar (where the sprouting eyes are located) and at least one tuber to support the plant as it begins to grow, the dahlia will grow just fine. 

Eye Visibility

Freshly dug late summer or early fall dahlias typically have more visible eyes than the same tubers/roots do in the spring. This is because as the dahlia is stored out of the ground, the eyes often shrink a little and pull back into the stem. So while the eyes are still present and viable, they tend to be harder to see. 

Our dahlias are held in cold stoarge to reduce premature growth of eyes and to avoid potential damage in transit or when planting. Learn more about that here: Dahlia Tuber Eyes