Taking cuttings a good way to grow more plant divas

There’s a compelling argument that all the work that goes into digging and storing dahlias for winter qualifies them as plant divas. But that’s also what makes them one of the easiest plants to quickly built a large stock of, something that’s an even bigger bonus considering that as the popularity of dahlias has grown, so as the price.

And now through April is a good time to make lots of new plants from last year’s tubers by taking cuttings.

The process is not difficult, but requires a heat mat, sometimes called a seed germination mat, and grow lights because the new young plants will be spending a lot of time growing indoors before it’s time to plant them in the garden.

Grab some tubers out of winter storage — it’s a good time to check on stored tubers to make sure the are still nice and firm and not shriveling or soggy — and divide the clumps if necessary. Then, using moistened potting mix, pot up the tubers in either individual 4-inch pots or a deep tub. I use a plastic dishpan with holes drilled in the bottom for drainage and, arranging the tubers mostly vertically, tuck them in close together, leaving only a couple inches between the tubers and the necks and eyes, where sprouts will emerge from, sticking out of the soil.

The potted-up tubers will send up shoots after sitting on a heat mat for a few weeks and will need some supplemental light.

Once the shoots reach about 3 inches tall with two or three sets of leaves, they can be removed from the tuber, either by doing a pull — grasping firmly at the base and gently rocking them back and forth until they detach — or by cutting with a very sharp knife or scalpel. Some gardeners like to leave a sliver of tuber attached to the bottom of the cutting. Remove the bottom set of leaves by cutting them off carefully.

Although dahlia cuttings typically produce roots easily, it’s a good idea to dip the end of the cutting in a bit of rooting hormone, then firm it into a tray of small cells prepared with moist potting mix. Cover with a humidity dome and leave the tray on the heat mat and under lights, checking to make the cuttings stay moist but not too wet.

In about three to four weeks, the cuttings will form roots — you can check by gently tugging on the leaves — and can then be potted up into small individual pots and grown on.

The tubers will continue producing sprouts, so additional cuttings can be taken, but they should be limited to a maximum of four cuttings per tuber so as to not expend the tuber’s energy. Once planted outside, cuttings will flower and produce tubers for storage the following year. The mother tubers can also be planted out.

Taking cuttings not only offers the opportunity to produce many more plants than you would get just from dividing tubers, it’s also a good way to satisfy the gardening itch in winter. Plus, it proves that maybe those diva plants aren’t so bad after all.