What You Need To Know About Dividing Perennials in October

Written by Susan B.

Perennials are every gardener’s best plant friend. After you plant them, provided you care for them properly, you can count on them to come back every year. Being able to count on having your plants come back year after year isn’t the only benefit you get from growing perennials. Most of them expand or multiply. Depending on their growth rate, you’ll need to divide them after a few years or more. We’re going to give you the information you need to know about dividing your perennials. 

Supplies You’ll Need to Divide Your Perennials:

  • A long-handled garden shovel
  • At least one large pitchfork
  • A spade 
  • A sharp garden knife
  • Some compost
  • Organic topsoil or cover soil
  • A pair of garden gloves 

You’ll use the spade or shovel to dig up the perennial clump you plan to divide. You’ll use the shovel to dig a hole again in the place or places where you intend to transplant your divisions. You will use the pitch forth to split the root ball in half. You’ll use the garden knife to separate the root ball into multiple plants. 

Why Divide Perennials?
Perennials represent the foundation of a garden because the plants come back year after year. As they age, they get larger, and for the first few years of growth, they fill out bare spaces in your garden and create a lush, elegant, and attractive environment. 

Overcrowding can cause plants to look haggard. They may produce smaller flowers, or there may be fewer flowers. In either case, dividing a plant will give it room to grow again. 

Failing to divide your perennials can lead to plant health problems. Overcrowded plants create the perfect hiding place for destructive insects and pests, and the ideal breeding ground for diseases.

How to Know When to Divide Perennials
The best time to divide most perennials is after they’re done blooming for the season. But there will inevitably be extenuating circumstances that necessitate separating them when that may not be the optimal time as recommended by experts. 

Reasons for which you may want to consider dividing your plants now include: 

  • They’ve become difficult or impossible to contain. 
  • The plant forms a clump but eventually starts to develop a bare spot in the center. The empty area will cause it to look unhealthy, and that will alter the appearance of the rest of your garden. If you divide it, the place where the bare spot is will regenerate itself, becoming healthier and more attractive. 
  • When a plant spreads out and forms a more massive clump, its size may cause it to be overcrowded in the spot where it is growing. Overcrowding forces plant roots to compete for the same resources — soil nutrients and water. If the plant roots can’t bring adequate water and nutrients to the rest of the plant, its overall health will suffer. 
  • Dividing perennials is a routine part of garden maintenance. Doing it helps ensure that plants will continue to be healthy and thrive. 
  • Dividing perennials is a cost-effective way to increase the number of plants you have in your garden. 
  • You should consider dividing your perennials when they start encroaching on the space of nearby plants. As they do so, they’ll cut off the airflow to surrounding plants and to the plant that is out of control. Without adequate airflow, the growing environment becomes one where destructive insects and pests can hide, but the situation also creates an environment conducive to disease growth and spread.
  • You may discover that plants are growing tall, but they keep losing their lower leaves. The top portion of the plant may be full of leaves. 

How Long  Can Perennials Grow Before They Need Dividing? 
Many perennials can grow for years without needing to be divided. They may grow at a rate that is slow and consistent enough that they don’t become problematic for several years.  There are some plants, including Black-Eyed Susan, Lamb’s Ear, and Yarrow, that make it necessary to divide them within a year or two of planting. Others that need to be divided every year or two include asters, blanket flower, and garden mums. And some perennials (including bleeding heart and butterfly weed) can thrive without ever being divided. 

How to Divide Your Perennials
Dividing a perennial essentially means that you’re breaking apart a large plant clump’s root ball. It probably sounds vicious and brutal, but it is the best way to show your love for perennial plants and help them continue to grow and thrive beautifully in your garden or on your property. 

The day before you intend to divide your perennials, soak the plant to help the root system get hydrated before you dig up the root ball. Removing the root ball from the soil is traumatic for the plant, so preparing it in advance can help reduce the impact of the shock. 

For plants that have extensive top growth, remove about ⅓ of the lower leaves so the plant can put more energy into establishing roots after you divide it. 

Decide where you want to plant the divisions before you dig them up and remove them from the ground. Dig a large hole to ensure that the roots have room to spread. Depending on the side of the root system, you’ll need to dig to an appropriate depth. 

Digging  Up Your Plants 
Use a spade or shovel to dig into the soil surrounding the plant’s root ball. After digging into the soil around the plant to gently loosen the dirt, start digging deeper into the ground around the entire circumference of the rootball. Dig to a depth that makes it easier for you to lift the plant and its rootball from the soil. If you have a large plant with a massive root ball, you may need to use the shovel handle as a lever to help you lift the root mass from the ground. 

Dividing the Plants 
Once you have your plants out of the ground, you’ll be able to divide them. For small root clumps, or rhizomes and tubers, you may be able to pull the rhizome, tuber and root mass apart with your hands. For massive clusters, and for enormous bulbs, you’ll need a sharp garden knife or a couple of pitchforks to split the gigantic clump or bulb apart. Once you’ve made the division, plant the pieces in their respective holes as soon as possible.  Water your transplanted divisions right away, and continue to keep the new transplants watered regularly – until the root system has a chance to establish itself in its new environment. 

Although it may sound like dividing perennials is a lot of work, the rewards of seeing the newly separated plants transplanted elsewhere make it all worthwhile. And the improved health of your plants will reward you with flowers when they start to bloom. If you’ve got any questions about proper tools to use, or when or how to divide your perennials, please don’t hesitate to come into one of our stores or call us. Our garden experts are always available to assist you. 

Do you like what you see? Sign up for our weekly newsletter to get content like this every week!

CLICK HERE TO SIGN UP!