Liatris is a genus of flowers that contains over 50 species! Most species are native to North America. Some species only inhabit a small part of the country, while others cover wide areas. They are very popular flowers for their showiness as well as their toughness. These are very hard plants to kill! In this article I will show you how I divide Liatris, and when to do so. For reference, I will be dividing Liatris Spicata in this article.
Liatris is one of the easiest perennials to divide! Divide Liatris by digging up the root mass/corm in early Spring once shoots emerge. Then, use a pruning saw, gardeners knife, or shovel to cut the corm up into two to three pieces. Replant the corms to the same depth in new locations and water.
Also, most of these flowers grow from bulb masses called corms. These are very similar to bulbs, in that they are an underground stem which produces the roots and stem/stalk for the flowers. As the Liatris plant ages and the years accumulate, the Liatris corm mass will grow larger and larger. Eventually, the oldest corms in the center of the plant will wither and cease to produce foliage or flowers. When this happens, it is time to divide the plant!
Tools for Dividing Liatris
You should have the following tools, or their equivalents before dividing Liatris Spicata
- Spade or shovel
- Small gardening shovel or trowel
- Garden knife, or pruning saw (for Corms, I really prefer the saw)
- Topsoil or potting soil for backfill
- Compost (optional)
Illustrated Guide for dividing Liatris Spicata, with Pictures
Please note that we have a short video showing this process at the end. So be sure to view that so you can see the process in action!
1 – Locate your Plant! Find the plant you wish to divide, and clear any debris or leaves away from it. This allows you to get a good idea as to the size, and if it should or should not be divided.
2 – Make sure the soil is moist. Water the plant and surrounding area thoroughly the day before you divide it. However, if you know the ground is very moist, or this is in early Spring/Late Fall, you can skip this step. But, if you are in doubt, water the ground thoroughly the day before dividing.
3 – Dig out the plant. Use your shovel to dig out the plant. Start your shove about 2-3 inches outside of the plant (5-8 cm). Dig at a 45 degree angle, working your way around the perimeter of the plant. Once you have gone all the way around, start to lift the clump out of the ground.
4 – Remove any excess dirt. After lifting the corm mass out of the hole, remove any large chunks of dirt attached. Use a trowel or small shovel to remove any excess dirt so that you can find the main portion of the plant. You can also use your hand and fingers to do this if the soil is moist/loose enough.
5 – Divide the plant. I like to use a small hand saw to cut through the plant. But a strong garden knife or even a shovel (for extra big plants) can be used too.
6 – Plant your Liatris Corms. Replant the corms, or corm-clumps. I generally replant one of them in the original location. Then I find another spot to plant the other half. You will likely need some extra topsoil or potting soil to help backfill the original plant. Also, with Liatris Spicata this isn’t required, but any transplanted plant will benefit from having some compost added to the hole.
But, even if a small corm breaks off, go ahead and plant it. The small corm I was holding in Step 5 reemerged just fine, as evidenced by the pictures below.
7 – Water your plants. Always give the plants a drink of water after dividing and transplanting.
8 – Wait for your plants to emerge. Once temperatures warm up your plants will reemerge.
I made a full comprehensive video on Liatris, from seed to bloom…and even to division. If you would like to see how to Divide a Liatris Plant in a video clip, just click below. I even show you footage a couple of months later, after the plants have re emerged. But the clip is set up to jump right to the part where I divide the plant – hope you enjoy it!
How large does Liatris need to be before dividing?
In general, I only divide mature plants that are at least 3-6 years old. Typically I don’t divide any plant that is less than 6″ diameter (18 cm). Smaller clumps can be divided, but you just need to be extra careful.
What time of year should you divide Liatris?
The best time to divide Liatris Spicata is in Early Spring or Late Fall when the plant is either dormant (not actively growing), or nearly dormant.
When perennials are dormant, you can dig them up and move them to a new location. Once the temperatures warm up and the growing season resumes, the plant will resume growing as if it had been in it’s new location the whole time! Kind of like waking up after falling asleep on the couch! “How did I get here?”
There are some other reasons why Early Spring and Late Fall are the best time to divide Blazing Star plants
- The temperatures are cooler, meaning there won’t be much of a heat load on the plant. So, it has less water requirements.
- Cooler temperatures also mean less evaporation of moisture on the ground.
- The ground is easier to work, since the soil is generally moisture
- The ground is generally moist, making keeping the plant hydrated less of a concern
When should you NOT divide Liatris?
During blooming, or after blooming the plant is expending all of it’s available energy to making seeds, or making flowers. Do not divide Liatris Spicata (or any other perennial) when they are blooming. Also, do not divide while they are forming seeds just after blooming. It is also not a good idea to divide a plant when it has been actively growing for some time. Transplant shock at this stage can generally kill a plant. So do not do it.
My general rule is that if the leaves are less than 3″ tall (7 cm), then I can divide it. Otherwise, it has to stay put until the Fall or next Spring.
How do I know my Liatris survived the division?
Well, if you divide your Liatris in Fall or extreme early Spring (like I do), then you just need to look for new growth. This new growth could be some tiny red foliage emerging from the top of a corm, or just wait until the temperatures hit 50-60F regularly, and you start to see green shoots!
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