How To: Divide Perennials
- info673
- Apr 16
- 4 min read
Dividing perennials is a fantastic way to keep your established plants healthy, encourage more vigorous growth, and get more plants for free! April in Scotland is a good time to do this, as the new growth is just starting to emerge, making it easier to handle and allowing the divisions to establish well before the main growing season.
Here's a step-by-step guide on how to divide perennials:
1. Identify Which Perennials Need Dividing:
Not all perennials need dividing every year. Look for signs that your plants could benefit from division:
Overcrowding: The plant has become too dense in the centre, and the inner parts may have stopped flowering or are showing signs of dieback.
Reduced Flowering: The plant is producing fewer flowers than in previous years.
Poor Vigour: The plant's growth seems stunted or weak.
Spreading Too Much: Some perennials spread aggressively and can encroach on other plants. Dividing them helps to keep them in check.
Generally, perennials that benefit most from division every 3-5 years include:
Daylilies (Hemerocallis)
Hostas
Bearded Irises (Iris germanica) (though they are often divided in late summer/early autumn)
Coneflowers (Echinacea)
Rudbeckia
Phlox
Sedum (Hylotelephium) (though they can be divided less frequently)
Many types of ornamental grasses
Avoid dividing:
Plants that have taproots: These are more difficult to divide and may not respond well (e.g., Baptisia, Papaver orientale - Oriental Poppy).
Plants that resent disturbance: Some plants prefer to be left undisturbed once established.
Plants that are currently in full bloom.
2. Gather Your Tools:
You'll need a few essential tools:
Spade or Garden Fork: For lifting the plant from the ground.
Hand Trowel: For smaller plants or for more precise work.
Sharp Knife or Saw: For cutting through tough root balls. A serrated knife can be useful.
Watering Can: To water the newly divided plants.
Gloves: To protect your hands.
Optional: Compost or Mulch: To amend the soil and help the new divisions establish.
3. Prepare the Area:
Water the Plant: If the soil is dry, water the plant thoroughly a day or two before you plan to divide it. This makes it easier to dig and reduces stress on the plant.
Choose a Cloudy Day: Dividing on a cloudy day or in the late afternoon will minimize stress on the plant and reduce water loss. Avoid doing it during the hottest part of the day.
4. Lift the Plant:
Dig Around the Plant: Use your spade or garden fork to dig a circle around the plant, about 6-12 inches away from the base, depending on the size of the plant.
Loosen the Soil: Gently work the spade or fork under the root ball to loosen it from the soil.
Lift the Plant: Carefully lift the entire plant out of the ground. You may need to use your spade or fork to lever it out if it's well-established.
5. Divide the Plant:
There are several ways to divide a perennial, depending on its size and root structure:
By Hand: For smaller, less dense plants, you may be able to gently pull the root ball apart with your hands. Work from the outside inwards, teasing the roots apart.
Using Two Forks Back-to-Back: Insert two garden forks back-to-back into the center of the root ball and push them apart. This can be effective for larger, more tangled clumps.
Using a Knife or Saw: For larger, tougher root balls, use a sharp knife or saw to cut through the roots. Ensure you have clean cuts to minimize the risk of disease. Aim for sections that each have a good amount of healthy roots and several growing shoots.
Aim for divisions that are roughly the same size and have a good balance of roots and top growth.
6. Prepare the New Planting Sites:
Choose New Locations: Decide where you want to plant the new divisions. Consider the plant's mature size and light requirements.
Prepare the Soil: Loosen the soil in the new planting holes and amend it with some compost if necessary.
7. Replant the Divisions:
Plant at the Same Depth: Plant the new divisions at the same depth they were originally growing. Look for the soil line on the original plant.
Space Appropriately: Space the new divisions according to the plant's mature size.
Firm the Soil: Gently firm the soil around the base of each division to eliminate air pockets.
8. Water Thoroughly:
Water the newly planted divisions thoroughly to help settle the soil around the roots and reduce transplant shock.
9. Aftercare:
Water Regularly: Keep the newly planted divisions well-watered, especially during dry periods, until they become established.
Mulch (Optional): Apply a layer of mulch around the base of the plants to help retain moisture and suppress weeds.
Avoid Fertilizing Heavily Immediately: Allow the plants to establish before applying a heavy dose of fertilizer.
Tips for Dividing Perennials in Scotland in April:
Be Mindful of Frost: While April is generally milder, late frosts can still occur. If a frost is predicted, you might want to cover the newly divided plants with fleece for a few nights.
Soil Conditions: Ensure the soil is not waterlogged when you are digging and replanting.
Choose the Right Time: Aim to divide perennials when the new growth is just starting to emerge, but before they have put on too much top growth. This allows the roots to establish before the demands of flowering.
By following these steps, you'll be able to successfully divide your established perennials, rejuvenate them, and enjoy more of your favourite plants throughout your garden!
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