by Barb Levisay
As the temperatures cool in September and October, it’s a great time to divide your perennials. Once they have finished flowering, the plants can be dug up, divided and planted over a larger area or moved to a new bed. The plants will benefit from the division and you will get more plants for free. In my garden, I’ll be dividing and moving hostas, echinacea (cone flowers), rudbeckia, salvia, coreopsis and mums as the flowers finish.
Choose which plants and where they will go
Most perennials will benefit from division every couple of years. Over time, you’ll notice more and more stems emerging from the base of the plant—which is a good sign that the plant is happy but means more roots are competing for water and nutrients. By dividing the plant, you help each rooted section to thrive on its own.
Before you start dividing, figure out where you will plant the divisions. Whether that’s spreading them out in the same bed or moving them to a new one, make sure the soil is prepped so you can pop them in the ground as soon as you dig them up.
This purple coneflower is getting dense and could benefit from division.
Dig and evaluate
Before you start to dig, cut off all the flower stalks, but keep the leaves intact for now. Dig the plant up including as many of the roots as possible. A good place to start with your spade is around the outermost leaves.
Dig up as many roots as possible when dividing plants.
Examine the plant to see how many divisions you think you can get. For some plants, you’ll be able to separate them with your hands. Mums, coreopsis and salvias are usually pretty easy to just pull apart—and you can often get a lot of plants from one clump.
Some plants, like echinacea and hostas are not so easy. For many first-time plant dividers, separating plants can seem very harsh. Use a sharp spade or even a bread knife to separate the plant into smaller pieces.
Sometimes it takes a little force to pry plants apart.
Once you have manageable pieces of the plant, examine them to identify those with undamaged stems and good roots. Pull them apart carefully looking for sturdy plants with substantial roots.
Trim off at one-third to one-half of the leaves from each division before you plant. Transplanting is stressful and it will be easier for the roots to support the plant with fewer leaves.
At least five individual plants divided from the original echinacea are ready to be planted.
Plant out divisions
It’s best to get them in the ground right away, but if you can’t plant your divisions immediately, keep them moist by wrapping them in wet newspaper.
Each newly divided plant should be placed in their predetermined spot and covered with soil immediately. Spread out roots as much as possible and cover with soil to about the same depth as the original plant.
The importance of watering
The initial soak of your newly divided plant is critical. The roots that have been exposed need to be in full contact with soil again—you don’t want any air pockets around the roots. Water all around the plant to make sure the soil is saturated to fully encase the roots.
To help the plants overcome the stress of transplanting, keep them watered to provide consistently moist conditions. Regular watering will help the roots get back to work gathering essential nutrients from the soil. The plants may look wilted for a few days but should perk up with continued watering.
Wait to divide grasses until spring
While most of our common perennials can be divided in fall, grasses will do better if you wait until spring. Wait until you see green sprouts emerging to dig and divide grasses. I’ve found the old bread knife to be the perfect tool for cutting a tough grass root ball into three or four pieces. Works like a charm.
Dividing plants is one of the most rewarding tasks in the flower garden. You help the plant, you get more plants for free and you can share your favorite plants with friends. What could be better? If you have a question, send a note to me at barb.levisay@gmail.com .