Clumps vs. Tubers
A clump is a collection of tubers that grow from a single tuber or seed during the dahlia growing season. A single tuber is usually divided from the clump and can be planted separately. A viable tuber will have a body, neck, and growing eye. Not all tubers on a clump will be viable tubers with those 3 pieces intact.
You can plant the entire clump or a single tuber and both will produce a plant and that plant will produce more tubers! The single tuber will turn into a clump and a planted clump will turn into a bigger clump. It works either way!
Is it better to grow from tuber or clump?
The growth rate is about the same for a clump and a tuber. Depending on the number of eyes more stems can emerge. Clumps offer some extra insurance because you get multiple eyes. This can be important for varieties that are less vigorous and is also helpful when growing conditions are not ideal.
A clump can take a bit more stress, heat or moisture or lack of moisture, better than a tiny tuber planted out in the field.
Since the sprouts / growing eyes originate at the base of the stem, there's no need for concern if some of the tubers get broken or detached in transit. Before planting, the broken tubers can be either sniped off or left attached.
(picture above: a clump with multiple eyes)
Should I divide the clump?
When you purchase a clump you may divide it into multiple tubers or plant the entire clump and divide it at the end of the season.
Dividing your dahlias is only needed every 2-3 years or if you are trying to multiply your plants. Careful! It can be challenging to find growing eyes without much practice.
We've planted entire clumps and single tubers and both produce beautiful plants!
Does Tuber Size Matter?
The short answer is, NO. Tuber size does not matter. It might look more impressive receiving a bigger tuber but as long as you plant a clump or a tuber with at least one eye, it will sprout and grow a plant that’s just as large and productive. Tuber size and the number of tubers per clump varies by season and by variety. Some varieties produce larger tubers and some smaller.