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There is Still Time to Transplant Perennials

University of Minnesota Extension, Stearns County News
October 11, 2017

Source:  Brenda Postels
Interim Extension Educator-Horticulture
University of Minnesota Extension
Stearns & Benton Counties

There is Still Time to Transplant Perennials
By Brenda Postels, University of Minnesota Extension

ST. CLOUD, Minn. (10/04/17) — Herbaceous perennials are non-woody plants whose tops die down in the winter.  They come back each year from the root system.  These include plants such as hosta, lily, iris, peony and even rhubarb.  People often wonder just how late in the season they can divide and move their plants without causing harm.

You can transplant perennials anytime until the ground freezes in the fall.  According to the University of Minnesota Climatologist Mark Seeley, the average date for our soil to freeze in Central Minnesota is November 27th. With that date in mind, there is still plenty of time to get out there and move things around.

Transplanting is done to move plants to a more suitable location, to make more plants (divide overgrown plants), and to reduce overcrowding.  Some plants do better when they get divided every few years.  On average, dividing every four years is recommended unless you want to reproduce more plants faster. 

In the fall, plants are no longer putting energy into new top growth, but are instead focusing on storing energy in their root systems.  Therefore, it is an excellent time to transplant because your plants will then have time to develop a good root system before hot and dry weather sets in next year. As long as the plant is green, it continues to build up carbohydrates and store them in its roots for next year's growth.  After the tops die back, you can safely cut back much of the top in order to make it lighter and easier to move.  

Before transplanting is a good time to amend the soil at your new site.  Time spent improving the soil will pay off in the long run by promoting good root growth.  Add compost, leaf mold or a few inches of top dressing, such as mulch, to increase the health of your plants and promote much more vigorous flowering.  Don't forget to water your new transplants and to keep them moist all the way up until the ground freezes.  Remember, those roots are continuing to grow until we get a good hard freeze.  With a new location and the roots off to a good start this fall, your plants will be perfectly set to start off great next spring.

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