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Is it time to divide your perennials? These questions will help you decide

Peonies divide nicely in the fall.
Peonies divide nicely in the fall. Kansas State University Research and Extension

If you have not figured it out yet, I love to garden.

There is something about working with soil and plants to create natural beauty. Watching plants grow and develop rewards my senses.

But I must admit there are some parts of gardening that do not stimulate my soul, like the regular garden maintenance of dividing and transplanting plants.

Maybe it is the routine that is unexciting. But dividing overgrown plants helps ensure good health and increased beauty in return. Early fall is a good time to divide perennials for renewed life in the garden.

How do you know when a plant needs to be divided? Here are three easy questions to ask.

First, is the plant producing fewer flowers? Second, is the center of the clump dead or looks more like a donut when growth begins in the spring? Third, has the clump grown so large that it takes up too much space in the garden or looks unkempt?

If you answer yes to any of these questions, it is time to divide.

Dividing perennials does take a little work. The clump must be dug up and broken apart into smaller divisions.

It can be pulled apart with bare hands, or — in some cases like ornamental grasses — the sharp end of a shovel or an axe. For the person who loves tools, a Sawzall makes quick work of this big job.

A nice size division for replanting varies with each plant, but there is an easy guideline. The division should contain around three to five eyes or growing points. Smaller divisions will take longer to reach peak flowering whereas larger clumps will need to be divided again sooner.

One drawback with fall dividing is tending to them in oncoming winter conditions.

Newly divided plants should be watered thoroughly at the time of planting and watered as needed over the winter to prevent drying out. Check the plants every few weeks to monitor winter moisture and determine if they need a drink on a warm winter day.

Perennials that flower very early in the spring are best divided in the fall. These plants are still growing underground even as they head into their winter slumber. Root development also resumes in the late winter as the plant prepares for spring growth.

Hostas and peonies are two plants that divide nicely in the fall. If the plant flowers in March or early April, fall dividing is ideal. This will include creeping phlox, pulmonaria and a few others.

Now it’s time for me to follow my own advice and give an overgrown clump of peonies in my garden some much needed attention.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? Email them to garden.help@jocogov.org.

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