Divide and conquer Making new plants

Ah spring! Time for division in your garden. What does this mean? Separating a plant into two or more pieces. This is a form of vegetative propagation in which all the divisions made from the same plant will be identical genetically. This is done for several reasons:

• a plant is gradually producing fewer or no flowers

• the plant seems to be pushing itself out of the soil

• the center of the plant is unattractively dying away while the other area still produces flowers

• the plant has gotten too large and is crowding its neighbors

• you want more plants without the expense

Please note it is not legal to propagate new cultivars of some plants. How would you feel if you developed a new cultivar and people simply propagated without your permission? Whenever possible, check before dividing and, for heaven’s sake, never include patented plants in a plant sale!

Many gardeners have told me their attempts at divisions have been less than successful. This could be from not dividing according to the type of roots and crowns the plants had. Clumpers such as daylilies and lamb’s ears have fibrous root systems; they’re easy to divide using only your hands. Each clump will have its own root system. Runners root along nodes (growing spots) and send up new growth from these spots. Examples include bee balm (Monarda), goldenrod, and aromatic asters. Usually, you need a spade.

Plants with tight woody roots are more challenging. Buds are tightly packed on the roots of these usually older plants. One must exercise care not to ruin the crown when dividing. Blue stem and peonies are examples.

The time of the year for dividing varies from species to species. You may have heard the rule about dividing summer blooming plants in spring; this is to prevent one from losing a season of bloom. However, we all know that sometimes we have so much to do in the garden that we’re forced divide at other times. The lack of flowers one year will be offset by more robust plants later.

Please keep in mind that not all perennials can be divided. For example, lavender is woody at the base, so make cuttings instead. Another example, lupines have a taproot; how can you divide that?

So how do you divide? The soil around the chosen plant should be moist but not sopping wet. This allows some soil to stick to the roots. Use a spade to dig around the perimeter of the plant. (I am rather hands on with this process; whenever possible, I sit on the ground and dig in one area with a hand tool to get a feel for the depth of the roots before using a spade for actual digging.) Do not pick the plant up by the crown! This is so destructive of the crown and the roots. Carefully support the plant underneath and move it either in a wheelbarrow or by sliding it on a tarp. Then, like a surgeon, divide it using a sharp saw or other appropriate tool.

The new plants should be place in new holes dug to the same depth as the original plant (unless it already heaved out of the soil!).

I like to make a soil mountain in the new hole, set the division on it, then carefully spread out the roots. I add garden soil and a bit of compost, but no fertilizer (it will burn the roots)! Water slowly with enough water to moisten the soil but not drown the roots. Tap down the soil. If it’s hot outside, consider using an umbrella or other shading method to protect the new plants from scorching.

Now, don’t ignore the new plants! In the division process, most of the microscopic root hairs broke off. Division success depends on the new plant replacing them; hormones released by the division indicate damage so the plant will work to recover. In time, you will notice the plants are recovering and growing.

For more information on individual species for plant divisions, check them out online or send me an email at caharlos@ verizon.net. FY

Carol Ann Harlos is an awardwinning retired math and science teacher, Master Gardener, beekeeper, writer, and speaker. She tends extensive gardens, including herbs, and loves learning from others and sharing her knowledge.