This time of year many gardeners are asking: Do I need to divide my perennials? How do I divide my perennials? And the most honest question of all- so what’s the worst thing that will happen if I don’t divide them?
Why we divide perennials is as important as when we divide them. Dividing perennials goes a long way to ensuring their longevity. Tight clumps can become weak or unsightly. Flag iris, for example, will form a large mass of plants and over time, develop a void in the middle, an area of no vegetation. Some plants, such as hostas can simply outgrow their allotted space or become too dominant in the landscape. Lily of the Valley can take over an area, and worse, escape into the lawn or area of a garden where ground cover is not desired.
Simply put, dividing perennials helps us to manage the plants’ growth, maintain the aesthetics of our landscape and provide plants for new gardens or to swap with other gardeners to expand our plant collection.
What To Divide
You can divide just about anything. Plants with exceptionally deep, substantial root systems do not like to be divided, such as Baptisia. If you are uncertain, call a professional or do as many of us did when we were cutting our garden teeth- experiment.
Divide plants that are cramped, showing signs of stress, are jumping their boundaries or are developing bald spots in the middle of the clump. Another rule of thumb, when the plants look perfect- it’s time to divide. If it looks great now, next season the plants may be too large for the garden plan.
Don’t divide as winter is knocking on the garden gate- your newly divided plants won’t have time to establish themselves in their new location.
Avoid the hot days of summer when there is already enough stress on the plants.
If it’s blooming, let it be!
Using a clean, sharp shovel dig around the drip-line of the plant.
If the plant has an exceptionally tight root clump, slice it with a shovel or use a saw. I have taken saws to massively overgrown hostas. As long as I left enough roots for each eye, the hostas came back without worry.
Some plants you can see a tangle of roots. Here’s a good time to use two clean garden forks to pry apart the mass.
Other plants you will see have developed individual plants and root systems that can be easily pulled apart.
Have your planting area prepped and waiting for the new divisions, water in well and don’t let it dry out!