Root Division: Multiply Your Medicinal Herb Harvest with These Plant Propagation Tips

Want an easy and free way to get more herb plants?

Who doesn’t, right? When I discovered how simple it is to multiply the herbs in my garden, I was instantly sold on root division. Having owned a medicinal plant nursery for years, I can tell you we propagated thousands of plants using this method. It’s a fantastic way to expand your herb collection and even swap root divisions with fellow gardeners—without the labor of starting plants from seed.

As a new gardener, I was lucky enough to attend my neighbor’s annual spring garden party, which featured live music, a potluck, and an epic plant swap. Beneath the shade of an ancient live oak, a long table overflowed with neatly labeled seeds of edible plants, ornamentals, native species, and medicinal herbs. Around the tree’s massive trunk, garden pots brimmed with freshly dug root divisions, ready to be shared.

What is root division?

Root division is the simplest form of  vegetative propagation. In plain terms, this means multiplying plants from an existing “mother” plant—no seeds needed. The process is simple: you dig up a portion of the plant’s root system, divide it, and replant those divisions.

Depending on the species and the age of the plant, you can get anywhere from one to twenty divisions from a single plant! For spreading plants, such as the mints (Mentha spp.), partridgeberry (Mitchella repens), gotu kola (Centella asiatica), jiaogulan (Gynostemma pentaphyllum), Monarda spp., and Arnica chamissonis, you can dig up the runners (stolons and rhizomes) and plant them in a new spot or container.

For clumping plants like elecampane (Inula helenium), valerian (Valeriana officinalis), Echinacea spp., motherwort (Leonurus cardiaca), meadowsweet (Filipendula ulmaria), comfrey (Symphytum spp.), calamus (Acorus calamus), lemon balm (Melissa officinalis), and culver’s root (Veronicastrum virginicum), you can drive a shovel into the center of the clump and pry free the divisions.

Personally, I prefer a gentler approach. Instead of the “shovel and split” method, I like to dig up the entire plant to get a good look at the root system—sometimes giving it a quick rinse in the process to remove the soil and see the root structure more clearly. I then divide the roots carefully using a garden knife (hori-hori), shovel, or pruners, and replant each section in a new location. Each division should contain either buds (if the plant is dormant) or leaves and shoots if the plant is actively growing. Just be sure to plant your divisions with the buds or shoots pointing up!

In the two images below, you can see a clump of calamus (Acorus calamus) being divided. The bottom image shows three pieces ready to be transplanted into a new spot in the garden.

What time of year is best for propagating roots?

Most gardeners divide their plants in the fall or spring when the plants are dormant, but the temperatures aren’t too cold. Personally, I prefer dividing in the fall because there’s typically less garden work than in the spring, and the roots can still grow even while the plant is dormant. In my nursery, I’ve planted small root divisions in the fall, and by spring, when I peek into the pot, I’m greeted by a robust root system—developed entirely without photosynthesis!

That said, early spring is also a great time to divide plants. If you’re working with a leafy, actively growing plant, cutting back some of the foliage is a good idea. This helps reduce the plant’s stress, as its root system will be healing and won’t be able to support as many leaves losing moisture through transpiration. After replanting your divisions, be sure to water them in well.

A seaweed or willow tea will further encourage root growth, boosting their chances of survival. Depending on various factors—season, species, division size, and the care you provide during the transition—your divisions may have a survival rate between 70-100%.

For herbalists, early spring and fall are also the best times to harvest roots. If you’re harvesting clumping or rhizome-forming medicinal plants, you can take part of the root system for medicine and replant the rest. This regenerative harvesting method allows you to gather herbs continuously without needing to replant a new crop—an excellent way to sustain your supply.

After you’ve harvested your medicine, visit our Storing Dried Herbs and Herbal Preparations article.

If you’re looking for a fun way to expand your garden variety, consider hosting your own spring seed and plant swap! It’s a great opportunity to meet other plant enthusiasts, discover new useful plants, and increase your garden’s diversity without the cost of buying new plants.

In the four images below, a clump of meadowsweet is dug up and pulled apart into smaller pieces, which are then ready for transplanting in the garden (or, in our case, into nursery pots).

Learn more about cultivation, identification, and uses for medicinal herbs in our 1,000-hour Herbal Immersion Program, which is the most comprehensive handcrafted online herbal course out there.

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