Divide perennials to boost health, beauty

Lauren Bethke

Welcome back to a new gardening season, and a new season of City Gardener columns! As our gardens begin to wake up from their winter rest, it's a great time to think about an often-neglected gardening task: dividing perennials. If you’ve noticed that your perennial plants have fewer flowers, smaller blooms, are dying in the center, or are just looking crowded, dividing them will probably help. Dividing perennials is a simple, rewarding task that can make a big difference in your garden’s overall health and appearance.
Essentially, dividing perennials is the process of digging up an established plant and separating it into smaller sections, each with its own roots and stems. This process helps rejuvenate older plants, prevent overcrowding, and encourage healthier growth. Over time, overcrowding can lead to stunted growth and increased susceptibility to pests and diseases. Dividing perennials every few years helps ensure that each section has access to sufficient nutrients, water, and space, as well as good airflow. Additionally, division is a cost-effective way to propagate and expand your garden, as the separated clumps can be replanted in other areas or shared with fellow gardeners. This simple practice helps ensure long-lasting, thriving perennials year after year.
It’s best to divide perennials when the plant is not actively blooming (or about to bloom) so it can focus all of its energy on regenerating root tissue and becoming established in its new location. In general, spring is the best time to divide later blooming perennials such as yarrow and bee balm (and ferns, although they don’t bloom), while fall is the best time to divide earlier blooming perennials such as lilies and peonies. Hardy plants like hostas can handle being divided in the spring or fall. And keep in mind that there are a few plants that don’t handle division very well – especially plants with particularly long roots such as goatsbeard, columbine, and baptisia. For these plants, it’s best to simply prune them without disturbing the roots. Check out the University of Minnesota Extension Yard and Garden website for a detailed list of plants and tips on how to divide them successfully.
In general, when dividing perennials, you should begin by watering the plant very well a couple of days ahead of time to ensure the soil is moist and easy to work with. When you’re ready to divide, dig up the entire plant carefully, preserving as much of the root system as possible. Gently shake or wash off excess soil to expose the roots, then separate the plant into sections. Depending on how dense the roots are, you can use a clean, sharp knife or spade to separate the plant into smaller sections, or pull them apart with your hands. Make sure each division has healthy roots and several shoots or buds, and remove any dead or damaged parts of the plant. Replant the divisions as soon as you can at the same depth they were originally growing. Water them well, and keep the soil moist until they are established.
If you can, try to divide perennials on a cloudy, overcast day – this can help reduce the risk of plants drying out during the process. And don’t worry too much if your newly divided plants look a bit droopy when replanted! This is very common, but with regular watering, they should perk up.
Dividing perennials is a simple and powerful way to keep your garden healthy. With just a bit of time and care, you can rejuvenate tired plants, prevent overcrowding, and even expand your garden at no extra cost. So, grab your shovel this spring and give your perennials the fresh start they deserve!
For more information, check out the University of Minnesota Extension Yard and Garden website. Extension resources are written by experts and contain the latest and most reliable research-based information. Happy gardening!