Perennials: how to divide
Plants that begin to produce more foliage at the expense of flowers may be overgrown. To determine if plants are overgrown, count the number of stems that emerge from the base. If five or more strong stems are present, the plant may need to be divided.
When dividing plants, pick a cool spell in the spring or fall, and gently dig up a clump with as many roots as possible. Expose the central rhizome or stem by gently shaking or washing away the soil. Then, with a sharp knife, cleanly slice the plant into several new pieces. Leave a minimum of two to three growing points, or it may take many years for the plants to recover. Place plants in newly prepared soil, and keep them moist until they re-establish. Share surplus divisions with friends.
It's a good idea to start with a single clump of one kind of plant until you master division, rather than risk an entire planting. Alternatively, when dividing particularly large plants, you may be able to remove a portion of a clump and leave the rest undisturbed. Replace the piece you remove with amended soil.
For more information, see the following Colorado State Extension fact sheet(s).
- Perennial gardening
- Choosing A Soil Amendment
- Vegetable garden: Soil Management and Fertilization
- Herbaceous Perennials
- Spring-Planted Bulbs, Corms and Roots
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Updated Friday, April 19, 2013