With their delicate flowers and varied hues, Achillea are perennial plants much appreciated for their hardiness and ability to enhance a garden. Like some other perennials, they benefit greatly from being divided every 3 or 4 years. This process not only rejuvenates the parent plant but also produces new plants free of charge to expand a border or share with other gardeners. Discover in this article our advice and step-by-step method to divide your Achillea.
Why divide an Achillea?
Over time, an Achillea planted in the garden for several years can become less floriferous. Dividing the clump stimulates its growth and flowering and therefore rejuvenates the plant. Division also provides new plants free of charge to enlarge borders or share with gardening friends. Finally, division helps limit the plant's spread within borders.
When to divide an Achillea?
Ideal period for dividing an Achillea is in spring, around March–April, when temperatures begin to warm and the plant enters an active growth phase.
Achillea can also be divided in autumn, around September–October, once flowering has finished, when the plant progressively enters dormancy.
Divide every 3 to 4 years to avoid weakening the plant.
Dividing Achillea
Equipment needed
- A spade well sharpened or a digging fork.
- A pruning shear or a garden knife, clean and disinfected.
- A hoe or a hand fork to loosen soil.
- Compost to enrich soil.
- A watering can.
Steps to divide an Achillea
1- Water the plant the day before dividing, to make extraction easier and reduce stress on its roots.
2- Loosen soil around the plant with a hand fork. Use a spade or digging fork to encircle the clump at a distance of 15 to 20 cm from the base. Insert the spade vertically into soil all around, then gently lift the plant by the rootball.
3- Once the clump is out of the ground, shake it gently to remove excess soil and expose the roots. Inspect roots and identify areas where they separate naturally. Use hands to divide if possible, or a sharp knife to cut clean sections. Ensure each division has vigorous roots and several shoots. Remove dead or diseased parts.
4- To replant new clumps, make holes slightly deeper and wider than each division's rootball.
5- Although Achillea tolerate poor soil, we advise adding some compost (place at bottom of hole) to encourage establishment and development.
Note: Achillea dislike excess water. Ensure soil drainage is adequate. For heavy, clay soil, mix two-thirds garden soil with one-third compost (or, if unavailable, potting compost) and add some coarse sand.
6- Place each division in its planting hole. Adjust depth so the collar (base of leaves) sits at soil level, then backfill with soil. Firm lightly to avoid air pockets.
7- Water generously to help soil adhere to roots.
Additional tips
- Achillea prefer a sunny position and well-drained soil, even if poor. Avoid heavy or waterlogged ground.
- Plant divisions at least 30 to 40 cm apart to give them enough room to develop.
- Apply a layer of mulch around plants to retain moisture and limit weed growth. Be careful, however, of slugs and snails that love young shoots.
- Maintain good moisture (but without excess) during first weeks to encourage rooting. Once established, Achillea tolerate drought well.
- A divided Achillea may take a year before regaining abundant flowering.
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