It doesn’t matter if you’re a gardening pro or you’re new to landscaping, dividing plants can be very intimidating. Do you take a cutting or divide at the root? And when is the best time to do it? We help simplify the process by showing you the best way to do it!
Dividing perennial plants is straightforward, and hostas are one of the easiest plants to divide. The key to success is doing it at the right time of year while following some basic steps.
Consider splitting your shade-loving plants in the early spring or early fall when they get too large for a space or if the plant is thinning in the center. Avoid doing it too frequently since the process does reduce the root system and sets the plant back a year or two in terms of its maturity.
Let’s get into the details!
Tools You Will Need
Dividing hostas is straightforward and doesn’t require much beyond your basic gardening tools. You’ll need something to dig them up out of the ground, something to split the clumps (your hands are always a great option), something to lay plants on to keep soil out of the lawn, and a way to water the divisions after transplanting.
It is best to divide your hostas at the beginning of the growing season or close to the end when cooler daytime temperatures mean more moisture in the soil and the plant doesn’t need as much water. This takes some of the pressure off the root system, allowing it to establish itself when the plant’s water needs are lower. This will also give it better chances of thriving without being riddled by pests and diseases.
Choosing one of these times of the year also gives the divisions time to start growing new roots before the heat of the summer or the cold of the winter.
- In the early spring, plan to split the plants when the leaves are beginning to emerge from the soil but haven’t yet unfurled. The soil temperature should be above 55°F (13°C).
- In the early fall, plan to dig them up and divide them about 4-6 weeks before the first frost. This gives the plants time to get established before the ground freezes and the plant goes dormant for the winter.
How to Divide
The goal is to minimize slicing off or damaging the roots. Hosta roots only grow from the tips. If they are cut, broken, or damaged, the root will not regrow from that point or branch into new roots. This makes it critical to be careful to keep as many roots intact as possible as you go through this process.
- If the ground is dry, water the soil well the day before. Having moisture in the soil will make it easier to dig than if it’s hard.
- Using a clean digging fork, begin inserting into the soil about 12″ out from the outer edge of the clump at an angle between 45 and 90°
- Continue to work your way around the perimeter of the hosta clump, gently prying the plant up out of the soil.
- Once free from the ground, lay it on its side on the tarp.
- Work as much of the soil free from the root ball as you can, using your fingers to untangle roots and dislodge soil.
- Take a look at the clump to discover natural breaks in the plant where it will divide easily, minimizing damage to the root system.
- Split the plants along the natural breaks using your hands, a straight spade, or a garden knife.
- Remove any leaves that don’t have roots connected to them or are damaged.
- Lay new divisions back on the tarp until you are ready to get them in the ground.
Getting the divisions into the ground is the same as planting other plants. It’s important that plants are planted at the correct depth and appropriate spacing—This will be dependent on the type of hosta you have. Dwarf varieties need 6 to 8-inches; small varieties 12 to 18-inches; medium varieties 18 to 24-inches; large plants 30 to 36 inches. Once transplanted, plants settle in quickly with little transplant shock.
- Dig a new hole twice the width of the plant and slightly deeper than the roots.
- Mound a little bit of soil in the bottom and use it to support the plant so that the division is planted at the same depth it was originally.
- Gently spread the roots out in the bottom of the hole.
- Backfill the dirt into the opening, gently tamping it down with your hands as you go.
- Once the hole is filled in, water the soil well to remove air pockets.
Hostas are a great way to practice this process, especially if you’re new to gardening. They are very forgiving and should be cared for like any other plant. The following tips are helpful for the division process itself. If you’re looking for general growing tips, check out our comprehensive hostas guide.
- Make sure all of your tools are clean, especially if any of them were used around diseased plants previously.
- Split clumps using your hands if at all possible. It’s the best way to minimize the chance of slicing roots. It isn’t always doable, though, depending upon the mass of the root ball and the variety. In these cases, you can use a flat spade or a garden knife.
- Try to work on cooler, shady days if possible.
- If you dig plants up and can’t get them transplanted immediately, pull the tarp into the shade and keep the roots damp. Your hostas will be okay for a day or two as long as they’re cool and kept watered.
- Avoid dividing any varieties until they are at least three years old. Giant varieties should be left alone until they are five years old or not divided at all.
- After transplanting the divisions, mulch around the new planting using leaf-mold if desired to help retain soil moisture and keep the soil cool—this aids in root establishment.
You’ll want to check out our shade garden article for design ideas or other great companion plants.