This can be done with a sharp saw, by two people and a bow saw, or even with an ax. Once you have sliced completely around the plant, you will see the plant beginning to lift out of the hole. The University of Minnesota is an equal opportunity educator and employer. Growing landscapes to help bees and other pollinators. What may seem like a pretty harsh or even destructive process dividing plants every 2 or 3 years actually encourages a perennial plants growth and stops them from becoming patchy and sparse. When dividing perennials, timing and technique are important. Perennials which need dividing include day lilies, asters (symphyotricum), ornamental grasses, irises and more – generally any which have the above root systems. Marie Iannotti is an author, photographer, and speaker with 27 years of experience as a Cornell Cooperative Extension Horticulture Educator and Master Gardener, Using Pitch Forks to Divide Perennial Plants, Dividing Plants Without Digging up the Original, How to Grow Nippon Daisies (Montauk Daisies), How to Transplant Rosemary Indoors for the Winter, How to Cut Back and Thin Perennial Plants. Exercise caution, as garden tool handles can break and send you tumbling. Spring is usually the best time for division because the plants are actively growing. All rights reserved. At this time, the leaves are not so developed that the root system can't take a little disturbance and still feed the top of the plant. Dividing plants is easy. The roots will not break cleanly, but the plant will recover. Prepare a hole for the new plants before you divide, as this will plant's time out of the ground and the stress on the root system. The ‘divide perennials’ list includes plants with rhizomes, such as irises or cannas. Each division should have three to five vigorous shoots and a healthy supply of roots. Primulas are a family of perennial plants that include primroses and polyanthus. Heger, Mike, Lonnee, Debbie & Whitman, John. The Best Time of Year to Divide Perennials. When perennials are divided, there is more space for roots to grow and absorb nutrients and water. You will probably hear some cracking as the plant splits. 1994. University of Minnesota Press, Minneapolis, MN. Wood, Christopher. Sometimes a densely rooted plant will resist, and it will take two people to pull the forks apart and split the plant. This is an additional advantage of watering the soil around the plant, as wet soil adheres better than dry soil. Ball Publishing, West Chicago, IL. Ideally, divide plants when there are a couple days of showers in the forecast to provide enough moisture for the new transplants. Keep them well-watered until new growth appears. Divide when the plant is not flowering so it can focus all of its energy on regenerating root and leaf tissue. Download the PDF or bookmark the Dividing perennials spreadsheet to find information specific to 125 common perennials. Once you have replanted the divisions, treat them like new seedlings. To keep your perennial gardens healthy you need to divide several kinds of perennials periodically. First, you dig up the clump of perennials that will be divided. Ornamental grasses tend to develop such heavy root systems that just digging them out of their hole is a challenge. If you can't avoid this, keep the replanted divisions well watered and protect the shoots from direct sunlight with horticultural fleece for a few days. How to Divide Perennials. Plants you can divide include hardy geraniums, hostas and daylilies; autumn-flowering perennials, such as rudbeckias and asters; ornamental grasses and bamboo. Peonies are a good example of a plant that prefers to be transplanted in autumn if it must happen at all. Keep pulling on the handles until the plant has completely split into two plants. Some plants, such as the coral bells above, have a woody crown. While spring is, generally speaking, the best time for dividing perennials, ornamental grasses, and grass-like plants such as sedges, those who really wish to "get it right" will want to treat each plant on a case by case basis.This is because some plants prefer to undergo the operation in … It’s a skill that every gardener should know how to do. However, these methods should all be undertaken with extreme caution, as you can hurt yourself a lot more than you can hurt the plant. When the middle of a plant dies out or looks like a doughnut, or if plants start to flop, fail to bloom or outgrow their location, they need to be divided. Any overgrown clump—or any clump that has simply exceeded the space allotted—is a candidate for division. And while many perennials can be divided in either early spring or early fall, some are very picky. Simply dig up the entire clump and then carefully divide the crown and root ball into two or more section, depending on the size of the clump. As a bonus, you'll get even more plants out of the division. You will still want to pre-water your plant and take as much of the root ball and soil as possible, but you do not need to dig and disturb the whole plant to reduce its size. Extension is expanding its online education and resources to adapt to COVID-19 restrictions. Primroses have short stemmed flowers and polyanthus have long stemmed flowers. You will find information on when to divide, how often to divide and other helpful tips. With their fall bloom, the summer heat is simply too much stress to divide and establish new plants. Smaller leaves and shoots will not suffer as much damage as full-grown leaves and stems. Manual of Herbaceous Landscape Plants. Dividing perennials in early Fall is more tricky, as you need to do this after the plant has bloomed, but before cold weather really sets in. Keep an eye out for clumps of plants that have grown two to three times their original size within two to five years. Plants divided in spring have the entire growing season to recover before winter. Late summer and early fall is the time to plant, divide, and transplant many different perennials, shrubs, and trees including spring flowering perennials. Division is a good way to create new plants for yourself or to share with friends. You know when yours need to be divided because the plants are growing in ever-denser clumps and the flower show isn’t as prolific as it was in previous years. A common maintenance chore in a perennial garden is that of dividing. Plants with tubers, such as day lilies, also need dividing from time to time. 1992. 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