Plant division is probably my favourite of all the horticultural chores we do. Not only does it make my hostas happier and healthier, but it also means I get a bunch of new plants for free to fill in the gaps in my garden.
Perennials should be divided for a variety of reasons.
- The first is if you wish to propagate your plant so that you can plant fresh seeds or enlarge your current bed.
- The second option is to prune a plant that has grown larger than you would like.
- The third reason is to rehydrate the plant if the centre begins to yellow or become scarce, or if it stops blooming.
A vertical close-up of a large cluster of variegated hostas in a bright garden with trees and a beautiful sky in the backdrop. Green and white printed text runs down the top and bottom of the frame.
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Plants that are overcrowded will never reach their full potential, and let’s face it, crowding negates the purpose of cultivating ornamentals in the first place. Plants that don’t have enough room look unkempt and distract from the overall aesthetic of your yard.
Diving plants is a multi-purpose gardening activity that allows you to boost the health of your plants while also getting free ones. We’re here to assist you if it’s time to divide your hostas for whatever reason.
I’m excited to get started, so let’s get started!
WHEN TO DIVIDE HOSTA PLANTS
Hostas, like other plants, benefit from division in the spring or fall.
The reasoning for this is that the plant will be less prone to heat stress and drying out. The weather is often more humid in the spring and fall, with colder temperatures than in the summer.
Fall is my favourite season because hostas are getting ready to go dormant, which means the leaves don’t need as much water and nutrients.
By this time, flowering should have ceased, and the plant will have had some time to rest and settle before resuming development in the spring. A horizontal close-up of an orange fall leaf on a hosta plant.
In the fall, though, you must be aware of any unexpected frosts or harsh freezes.
To be on the safe side, cover the plant with pine boughs or cardboard anytime temperatures are expected to fall below 33°F for the first few weeks after dividing.
As soon as the weather heats up again, you can remove the cover.
If you divide your plant in the spring, it is more likely to have stunted growth or get stressed as it prepares for the busy growing season ahead.
If you decide to work in the fall, you should begin about four weeks before the first average predicted frost date.
When the shoots have sprouted from the earth but have not yet unfolded in the spring, divide them. (This is also, by the way, the greatest time to eat the shoots!)
In the spring, a close-up horizontal photograph of young hosta shoots pushing through the dirt.
Having said that, I’ve separated hostas in the middle of the summer when they became too huge for my garden and they didn’t seem to mind. If you absolutely need to get the task done, don’t feel obligated to wait.
So, when is it appropriate to divide a hosta? It can take four or five years for some of the larger hybrids and cultivars to achieve maturity.
It takes two or three years for smaller ones to grow. If at all possible, wait until your plant has reached maturity before dividing it.
It’s not the end of the world if you need to divide a plant that has become pot-bound or want to propagate a new plant quickly. Just bear in mind that as a result, your plant will take a little longer to mature.
PREPARATION TIPS ON HOW TO DIVIDE HOSTAS PLANT
Tips for Preparation
Give your infants a great, lengthy drink the day before you want to start your work, assuming it isn’t raining.
The dirt should be loose and workable. However, you don’t want it to be overly wet. Wait till the earth has dried out a little if it has been wet.
Then, if the leaves are still visible, clip away any yellow or dead foliage, as well as any scapes (the flower stalks).
It’s a good idea to prepare the area where the divisions will be planted before you dig up your present plants, presuming you’ll be replanting the divisions rather than simply lowering the overall size of your plant.
This causes less shock because the roots are exposed to the elements for a shorter period of time.
Read our growing guide for advice on how to set up your hostas in the ground or in a container.
When selecting where to relocate your plant, avoid moving it from a shady to a sunny location in the spring or summer (another reason why I prefer to do this garden task during the fall).
While an established hosta can generally withstand a lot of suns, a fresh division is more likely to get sunburned and even die.
If you wish to relocate your divisions to a more sunny location, first place them in a container and then gradually bring them into the sun over many weeks.
Move the container to a brighter position every couple of days, adding around 15 minutes of exposure each time. This will assist it in acclimating to the sunnier conditions prior to transplanting.
DIVING YOUR HOSTAS CLUMP
Let’s get your spade out and start digging. If you’ve been using your shovel in other parts of the garden, it’s a good idea to disinfect it first. Wipe it down with a bleach-to-ten-parts-water solution to prevent disease transmission.
Now dig around the full border of the clump, about six inches away from the stems. Insert your spade under the plant and tilt the handle back toward yourself to provide leverage, easing the plant out of the dirt.
In a close-up horizontal shot, a gardener digs out a small hosta plant with a shovel.
Dig as deep as you can because the roots of a large, fully formed plant can stretch up to 18 inches downward.
The goal is to remove a significant portion of the root system. Your divisions will most certainly survive as long as you get at least some undamaged rhizomes.
One of the best things about hostas is how tough they are. Pull the clump from the ground and place it in the shade on a tarp, cement patio, or lawn. Clean the roots by rinsing them and inspecting them. Remove those that appear to be lifeless or mushy.
You can skip this step if you like, but it’s especially helpful if your garden has had any rot or fungal issues.
If you’re transplanting in the summer while your hosta is actively growing, don’t rinse it away because it can act as a protective barrier.
It’s easy to know where to divide the plant now that you can see the roots plainly. Squat down and examine the connections between the roots and the rhizomes, as well as the connections between the rhizomes and the stems and leaves (the crown).
Don’t worry if you don’t see any rhizomes because some species have fibrous roots instead of rhizomes.
The crown will most certainly reappear and put on new growth after transplantation as long as there is some rhizome attached to the kinds that do have them.
But, just to be cautious, I like to divide each clump with a large clump of rhizome and a few buds. I usually divide one 18-inch-wide cluster into four sections.
From the bottom of the frame, a close-up vertical shot of a pair of scissors cutting through the root ball of a hosta plant.
Before separating the roots and crown, make sure your equipment is clean, as indicated previously.
With a sharp knife, scissors, or the spade you used to dig out the hosta, sever the plant at the proper areas.
In a close-up horizontal shot, a gardener cuts a hosta plant into two halves for replanting.
If you’ve experienced rot or fungal problems, now is the time to treat the roots with copper fungicide dust. Lightly dust all of the roots and the base of the crown before placing it back in the ground or in its container.
This copper fungicide is a savior when it comes to copper fungicide. Because it acts against a wide range of fungal diseases including rust and blight, I always keep some in my gardening gear.
It’s also suitable for organic gardens. Isolated on a white background, a close-up square image of a package of Bonide Copper Fungicide.
BONIDE COPPER FUNGICIDE
If you don’t already have some, Bonide at Arbico Organics sells one- and four-pound quantities of this product.
It’s now time to relocate those divisions to their new location. Treat them like you would any other young transplant, as detailed in our handbook.