What are they?

Mini tuber clumps, also called pot tubers, are a popular way to grow dahlias in Great Britain and many other countries. But apart from the dried-out tuber clumps commonly sold at big box stores each spring, they are not yet common in the United States

At Dahlia Doctor, each pot tuber begins life as a rooted cutting propagated by hand then grown to maturity in rich, custom-blended soil in its own small pot. The dahlia grows through an entire season in our temperate Pacific Northwest garden, where it blooms and produces a miniature clump of tubers just like its larger cousins planted in the ground.

At the end of its growing season, the stem of the dahlia plant is cut down and the tubers are lifted and left in a single intact clump. Although small in size, each tuber contains the same genetic coding needed to grow an exact copy of the dahlia plant that produced it.

The easiest way to grow mini tuber clumps is to plant them directly in the garden after all danger of frost has passed, just as you would plant an individual dahlia tuber that was divided from a full-sized clump. Because our pot tubers have been kept intact through their entire growth cycle, you are assured each one has viable growth points, called "eyes", from which new stems will grow to produce a full-sized dahlia plant.

An experienced dahlia grower may choose to split the miniature clump into two or more sections, each of which can be grown into a separate plant. If desired, the mini clump can be started indoors under light early in the spring, allowing the grower to take cuttings from which to propagate more plants. Ian Sutherland, an experienced dahlia grower in England, reports "Pot tubers usually start to product cuttings earlier than field tubers." Our experience is that since there are multiple small tubers in the clump, they are capable of producing robust growth whether planted directly in the garden, or used to produce cuttings.

We have an article in our Knowledge Center that tells all about pot tubers. Have a look at Propagating Dahlias Using Pot Tubers