How to Divide Perennial Root Clumps in 7 Easy Steps (And Why You Should)

Feeling that itch to tidy up and organize everything in sight? Yeah, we feel it too.

Spring is the best time to get out and start preparing your garden for the upcoming season. One essential—but often overlooked—spring cleaning garden task is perennial root division. While waiting for the weather to warm up enough to plant something new, it’s an excellent time to take stock of what you already have and spread crowded perennial plants around your landscape. 

Dividing perennial roots is an easy way to encourage the plants you already have to grow and bloom more vigorously, as well as propagate more plants to use in your landscape for free. It’s a process that is as simple as planting, but clean tools are essential, and time is of the essence.

Keep reading to learn more about the benefits of dividing perennial roots and how to do it. 

Why divide perennials?

Perennials are low-maintenance, it’s true—but even then, they’re not exactly zero-maintenance.

Most perennials benefit from at least a yearly pruning and maybe the occasional watering in a drought, and that’s about it. But for optimal growth, you’ll want to dig up and divide perennials every three to four years.

An article published by the  University of Minnesota explains that perennial root division has three main benefits: to rejuvenate the plant and stimulate new growth, to control the size of the plant, and to increase the number of plants.

Perennials will keep growing and spreading, and periodic root division is necessary to keep the plants from getting too big to manage. Overcrowded plants are more susceptible to diseases and may not bloom as proficiently as plants that have been divided.

Root division, just like pruning, encourages plants to direct more energy towards regaining the vegetative growth that they have lost. This results in fuller, bushier plants with more blooms. Plus, dividing perennials is an easy way to increase the number of plants in your garden without spending extra money!

When to divide perennials

Ideally, you want to divide perennials when they are not flowering while the plant is still in a vegetative state of growth.

For most plants, this will be either in spring or fall. A good rule of thumb is to divide spring and summer-blooming plants in the fall and to divide fall-blooming plants in the spring—around the same time you would plant these perennials.

In spring, it’s better to divide earlier rather than later because the shock of transplanting may cause plants to bloom a little later than usual. Plants can be divided as soon as the soil is workable and new shoots have emerged.

For fall divisions, wait at most four weeks before the first frost to dig and divide so that the plant roots have time to recover before winter.

How to divide perennials

Digging up and dividing root clumps is no more complicated than planting perennials in the first place—the only difference is that you must use sanitized tools to make the cuts, and you want to move relatively fast to minimize transplant shock.

  1. Check the forecast

  2. If you can, save root division for a cloudy day with rain in the forecast since an overcast day will be less stressful on new transplants than a warm day with full sun. Rain will help ease transplant shock, or you can water the plants diligently until they are well established.

  3. Gather your tools

  4. You’ll need a shovel or digging fork and garden shears, at minimum. Depending on how big the root ball is, you might need a hori-hori knife or even loppers to make divisions. 

    Whatever tool you choose, sanitize it with a diluted 1:10 bleach solution, or spray your tools down with either hydrogen peroxide or rubbing alcohol to clean the blades. 

    Clean your tools between every root clump to avoid spreading pathogens and diseases between plants, and keep your hands safe with these durable (and cute!)  Gardening Gloves.

  5. Lift the roots

  6. Using a shovel or a digging fork, gently dig the roots up out of the ground, giving the plant a wide berth of at least eight inches from the base of the plant. You want to avoid too much ripping and pulling to save as many roots as possible.

    You can also use the shovel to cut through the clump and dig out a section without lifting the whole plant—just do your best to make a clean cut.

  7. Divide the root ball

  8. Now that you have the root ball above ground, shake off as much dirt as you can. You can also wash away the dirt by soaking the root ball in water or spraying it gently with a hose.

    Some plants have natural segments that are easy to see and divide. With other plants,  you’ll need to decide where the divisions are yourself. This is scary but trust us—your plants will come back stronger!

    Make a clean cut with a sharp, sanitized tool, and ensure each piece has at least a couple of leaves and a good-sized piece of root to ensure that segment will regrow.

  9. Replant the pieces

  10. It’s essential to think about where you plan to plant the divisions before you begin so that you can immediately transplant them. 

    Ideally, the new location will have similar light conditions and soil type as the old one unless you’re moving your plant to an area better suited to its growing needs. Whatever the case, familiarize yourself with each plant’s growing requirements and ensure it is in an area of the landscape where it will thrive.

    It’s crucial to plant divisions at the same depth as the plants were before. Planting too deep or too shallow could harm plant growth, so do your best to place the crown of the plant (the point where the stem meets the roots) just under the soil's surface. Sometimes you can see a line of dirt on plant stems that marks the original soil depth—use that as a planting guide.

  11. Water the transplants

  12. Give plants a deep soak as soon after planting as you can. If there’s rain in the forecast, you can let nature do the rest. If the weather is dry and sunny for over a day, try to water the new perennial plantings daily for a few days. 

  13. Mulch the transplants

Mulching conserves water and offers new transplants some protection from the elements. Plus, mulching suppresses weed growth, and we think it just looks nice in general.

What perennials need to be divided

Most perennials will benefit from root division, but these perennials require it:

If you’ve never divided perennials before, you might be a little afraid of hurting your plants, but don’t let that stop you!

Root division is safe, routine maintenance that keeps your perennials healthy and thriving. Digging up perennials is easy, and there’s no danger to your plants if you use clean tools and water the transplants thoroughly.

Regularly dividing perennials will keep your favorite plants looking fresh and will save you money in the long run! So grab a shovel and get to it. Of course, you can always buy a new plant through our   Online Store.