Question of the Week – Number 3: January 24, 2019
“I want to divide my cannas and garden mums. When can I do that?”
Someone did ask about cannas on the air this past weekend, but basically these plants are standing in as surrogates for the many questions I’ve had about dividing summer- and fall-flowering perennials the past couple of weeks.
Cannas must be dug and divided before new shoots begin emerging. That will be very soon now, starting in South Texas and quickly progressing to the north.
Remember the old axiom: “If it blooms in the spring, you dig and divide it in the fall. If it blooms in mid-summer or fall, you dig and divide it in very early spring.”
Garden mums’ new shoots are only an inch of two tall now, but they will start growing very quickly very soon. Pinch out the growing tips. Dig the clumps and break them into smaller plants before resetting them into well-prepared garden soil on 18-inch centers.
So cannas and mums would both be dug and divided sometime in February – early February in South Texas and mid- to late February farther north. You want to get it done before they start sending out their new shoots. They grow extremely rapidly in early spring, so any delay could render digging and dividing moot for another year.
Other plants to move now…
Other plants you can dig and separate sometime in the next few weeks include ornamental grasses, gloriosa daisies, purple coneflowers, mallows (hardy hibiscus in all of their types), fall asters, summer phlox, paper plant (umbrella plant), ferns, and as their tops die back to the ground, fall-flowering bulbs spider lilies, naked lady lilies, fall crocus and schoolhouse lilies (oxblood lilies).
There’s a special technique to digging and relocating each of these types of perennials. Read up ahead of time and do the work in a timely and careful way. You’ll be handsomely rewarded for your effort.