Although spring and fall are popular times for splitting and dividing perennials, many perennials can be divided as soon as they finish blooming in the middle of summer.
And summer dividing holds big advantages for both you, and your landscape!
Why & How To Divide Perennials In The Summer After They Bloom
Dividing plants in the summer gives you the opportunity to view your flowerbeds in full growth mode. This means you can truly tell which plants are growing too close, or too large. Even better, you can easily see where you need to add additional plants to fill open spaces.
Unfortunately, that isn’t the case in the spring or fall when plants haven’t developed, or have died back. It can be difficult to know just what areas the plants will really grow to fill.
Why is this so important? Because filling your flowerbeds is vital to snuffing out weeds and needing less mulch. Both great methods for keeping your beds maintenance-free, and you stress-free! (See: How To Keep Your Flowerbeds Weed Free)
But summer dividing also is a big help for the perennial plants as well. By dividing in the summer after they bloom, plants have plenty of time to establish new roots before winter.
Not only does this give them a better chance of survival, but it allows plants to be completely ready to grow and bloom in full force next spring.
That simply isn’t the case for many spring or fall divided perennials that need time during their first year to get growing.
How To Divide Perennials After They Bloom In The Summer
Before we look at dividing plants in the summer, it’s important to know there are a few perennial plants to avoid.
Most notably, ornamental grasses. With their fall bloom, the summer heat is simply too much stress to divide and establish new plants. In addition, small shrubs, roses, etc. are not good candidates for summer splitting.
But with that said, there are many that can! Like daylilies, hosta, coral bell, coneflowers, daises, black-eyed susans, and nearly every other perennial plant as soon as it completes it’s bloom period.
And being sure the plant has completed blooming is important. It can be difficult to transplant perennials while in bloom. All of their energy is focusing on blooms, and transplanting at this point can easily be deadly to the plant.
Summer Transplanting Specifics
For daylilies and hosta plants, the easiest method is to cut the plant back completely back to within an inch of the ground. Then dig up the plant and use a sharp shovel to divide into new starts.
As for size, small divisions will create smaller plants, larger divisions, larger plants. As a good rule of thumb, keep root sections to around 3″ in diameter for manageable plants.
Replant with an ample amount of compost and keep watered well through the summer heat. By late summer / early fall, you will see new foliage begin to emerge.
Dividing Additional Perennials
For nearly all other perennials, begin by cutting any spent blooms and stems back to the ground base. You can leave the foliage in tact to help shelter the new plants as they re-establish their roots.
Dig up and split the plant with a sharp shovel or knife. A Hori Hori Knife is excellent for this task! Like with the hosta and daylilies, replant with compost and water well.
Depending on summer heat, you may see the top foliage die back or even completely off. Don’t worry, continue to water and new leaves and foliage will begin to appear.
Create A Holding Bed In The Garden
If you don’t happen to have space right now for transplants, create a holding bed in an open area of your garden. It is a great way to have plants at the ready, or to even give to friends, family and neighbors next spring.
We created holding beds when we were building our home to have transplants ready to go when finished. It was a huge saving on our budget from having to purchase from new. To this day, we still create holding beds to keep extra plants at the ready.
Here is to dividing perennials in the summer, and creating new plants to fill your landscape! Happy Gardening – Jim and Mary.
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