How to Divide and Multiply Your Spring Blooming Perennials

Keeping perennials healthy can be a challenge. Here’s a guide for dividing spring blooming plants to ensure they spread and have enough space in your garden to thrive. You’ll learn which plants are best for splitting and the steps to do so successfully.

There’s nothing more satisfying than putting work into a garden that you will enjoy for years to come. Perennials are an essential part of most gardens, bringing color and continuous growth for many seasons. However, keeping perennials looking their best requires some maintenance—including separating plants when they grow too large.

Dividing perennials is essential to avoid overcrowding and to keep your plants thriving. This article provides everything you need to know on how to divide spring blooming perennials.

Why Divide Perennials

Beginning gardeners often make the mistake of assuming that perennials need little maintenance. In reality, many perennials have vigorous growth habits and send up lots of new shoots and roots that need to be maintained.

Over time, this creates crowding issues. The plant begins to compete with itself for access to water, light, and nutrients. The result? A frailer plant overall that grows weaker stems and puts out fewer, smaller flowers.

Dividing a perennial plant reduces its stress and gives it more space to grow and thrive. As a bonus, part of the plant can be transplanted elsewhere if you wish to expand your garden or plant the perennial in a different location.

Which Plants To Divide

Not all perennials are appropriate for dividing. Some plants, such as lupine and butterfly weed, grow with one large taproot that doesn’t take well to being split.

Plants with fibrous roots thrive when divided and get rejuvenated in the process. These include daylilies, ornamental grasses, black-eyed Susan, and most hostas.

Be sure to check with a plant expert before dividing your perennial to ensure the variety can handle it.

When To Divide Perennials

As a general rule, it’s best to divide perennials every three years. However, plants that grow in fertile soil and plenty of sun will grow faster and may need to be split more often.

Ideally, you want to divide spring-blooming perennials before the plants genuinely need it. However, don’t wait until they are overcrowded, as the plants will already experience negative consequences from the space pressure.

Fall Is Best

The best time to divide spring-blooming perennials is in the fall because you won’t disrupt their blooming cycle. Ensure you give the plant enough time to get established before the ground freezes by dividing at least six weeks before you expect snow.

Spring Is Fine

Early spring will also work just as the plant shows new signs of growth. This will give its roots plenty of time to acclimate to new conditions before the summer heats up. Just note that plants that are divided before flowering will take longer to become reestablished and may produce minimal blooms.

For best results, plan to divide your perennials when the weather is cool and wet. This reduces stress on the plant by ensuring its roots won’t dry out during the transplanting process.

How To Divide Perennials

Once it’s time to divide your perennials, water the plant thoroughly and prepare the place where you plan to replant it. Consider adding organic fertilizer to the soil to help ease the transition. Remember, cloudy days are best!

You can then dig up the entire root clump you plan to split. Make sure you pull up plenty of soil with the roots to avoid accidentally cutting them off. Place the whole plant on a tarp and shake it gently to remove loose dirt.

Next, take a sharp knife and examine the roots. There are three basic root systems to be aware of:

Spreading roots: These roots spread outward from the original stem and are usually shallowly rooted. You can pull them apart by hand into individual plants.
Clumping roots: These compact root systems are usually thick and fleshy. They grow downwards and are closely intertwined. Divide them by cutting the crown into pieces, ensuring each piece has a few buds attached.
Rhizomes: Essentially thick, fleshy stems that grow underground, rhizomes spread outward from the plant and have the potential to grow on their own with little fuss. Make sure you divide them with a sharp knife and keep a few buds on each piece.

Cut where you see a natural separation in the roots, or simply slice the plant in half. You can continue to cut until you have multiple sections, making sure each clump has visible green growth above the ground and is at least 20% of the original plant.

Replanting Divided Perennials

After dividing, you can replant each smaller clump into prepared soil, ensuring they are planted at the same depth as the original plant. Ensure you pack the soil down around each plant to minimize air space and ensure the roots make contact with the ground.

You can ease the transition by cutting off the top six inches of the plant so it puts its energy back to root growth. Water the divided plants immediately after planting and keep them well-watered for several weeks.

It’s always best to replant on the same day you divide. If that’s not possible, wet the roots and store the plants in a cool, dark place until they can get in the ground.

Caring For Your Perennials After Dividing

After dividing, perennials may look stressed and shrink back. However, you should see signs of new growth within a few weeks. Refrain from applying nitrogen fertilizer for at least a year, as it will encourage the plant to put energy towards leaf growth at the expense of its roots.

For fall plantings, it’s smart to apply thick mulch around the base of each perennial as soon as the ground freezes. This will protect the vulnerable roots systems against freeze and thaw cycles.

While perennials might not be as carefree as you first thought, dividing spring-blooming plants is a straightforward process that will benefit them for years to come. Take the time to do it right, and you’ll continue to enjoy an abundance of healthy perennial plants in your garden.