How to Divide Perennials (So You Can Make Lots of Free Baby Plants)

If you love plants, you know that both annuals and perennials belong in your garden for season-long beauty and color. But whether you’ve planted them yourself or moved into a home with a mature garden, sometimes perennials need a little TLC. “If your perennials have been in the garden for a few years, they may become overgrown or start crowding out other nearby plants,” says Darren Barshaw, product representative for Darwin Perennials, a perennial plant breeder and producer. “They also may not be blooming as well as they used to, which is a sign it’s time to do some divisions.”

Dividing your perennials is super easy and just requires some digging. Not only will you get more plants (for free!) but you’ll also rejuvenate them, stimulate growth and can even swap plants with other gardeners. 

Here’s what you should know about dividing perennials, as well as answers to commonly asked questions about caring for your newly separated plants. 

1. Gather your tools

Namely, a sharp garden spade, a garden or utility knife, and digging fork. Depending on whether your soil is heavy clay or sandy, different tools may be more helpful in lifting up and cutting through the plant. For example, some perennials, such as Siberian irises, have fibrous roots, so you’ll need to use a knife to cut away pieces. 

2. Decide how big a piece you want to take from the plant

You can leave some of the plant intact or dig up the entire plant if it needs moved to a new location. Use your digging fork to work around the edges and lift up the whole thing, then break into multiple pieces. Or use a spade to chunk off a section along the edge. “Don’t be shy,” says Barshaw. “You need to cut through roots and you’ll lose a few, but trimming actually stimulates the plant to grow new roots.”

3. Choose a spot that's sunny (or shady) enough for your transplant

For example, if you've divided hostas, you'll want mostly shade, whereas peonies need full sun (defined as 6 hours or more of sunlight a day).

4. Dig a hole about 2 to 3 times the size of the plant's root ball

Place it in the hole at the same depth as it was originally, then back fill the soil, pat down firmly and water well. Water at least once a week until the first frost (more often if it’s hot and dry). Where you removed the chunk from the original plant, fill in the hole with compost and fresh soil.