Rooted Dahlia Cuttings Tuber Growth Experiment 2023

In summer 2023, we did a fantastic experiment with KA’s Mocha Katie dahlias, to demonstrate what tuber growth looks like when taking dahlia cuttings to root at different points in the year. This year’s experiments followed many variations from 2022, and confirmed quite a few things, including:

1. As outdoor day-length increases, our cuttings (both indoor and greenhouse!) root more quickly.
2. Planting out rooted cuttings in May/June produces the largest tuber clumps, no matter when the cuttings were taken/rooted in the range January – March.
3. Planting out rooted cuttings in July/August still produces save-able (although probably not Grade-A “salable”) tuber clumps.
4. The sweetest spot for reliably large tuber clumps were group 2 – cuttings taken from cuttings in February and planted out in May. These cuttings had 120+ days to make good tuber clumps, and they sat in the greenhouse waiting to be planted for fewer days that group 1 

KA’s Mocha Katie, besides being one of my top favorite blooms, has a gorgeous plant habit and is a super productive bloomer and tuber-producer for us. This dahlia also roots easily, so taking cuttings from cuttings is not difficult. (Virus-tested, tissue-culture propagated rooted cuttings of KA’s Mocha Katie will be available in our pre-sale this fall!)

We took cuttings from tubers in January, and cuttings from cuttings (this link to an update from August 8!) in March, May, and July, and planted them out in the field, and their clumps (dug October 11, 2023) are featured in the pictures below.

1. January 15th cuttings/planted out May 1st
2. February 5th cuttings/planted out May 9th
3. May 15th cuttings/planted out June 24th
4. June 25th cuttings/planted out August 1st

Note: We used numbers 1 through 4 on the pictures to identify which plant/tuber clump is which.

Group 1- January 15th cuttings/planted out May 1st

This produced the most foliage.

Group 2 – February 5th cuttings/planted out May 9

This produced the largest tuber clump with foliage slightly shorter than Group 1.

Group 3 – May 15th cuttings/planted out June 24th

These tuber clumps are still viable! We will split them in half and plant them in our fields next year.

Group 4 – June 25th cuttings/planted out August 1st

Just like with group 3, we will split these in half and plant them in our fields next year.

I hope this experiment gives you moments of hope if your tubers are damaged, or if you aren’t able to purchase as many of a certain variety as you wish, because taking cuttings from dahlias is a fabulous way to increase your treasured collection!