Why overgrown chives stop performing

Chives are among the most generous herbs a UK garden can hold, but that generosity has a limit. Left undisturbed, a clump will bulk out year after year until the bulbs are packed shoulder to shoulder, competing for moisture and nutrients in ground that has long since been exhausted. The first sign is usually a change in the leaves: instead of the tender, bright green blades you want for snipping over new potatoes, you get a dense thatch of thin, tough, yellowing foliage and far fewer flowers.

In a cottage-style border this matters twice over. Chives earn their place not just in the kitchen but as a soft, hazy edging plant whose pink-mauve pom-pom flowers feed early bees in June. A congested clump gives you neither good leaf nor good bloom. Dividing restores both, and spring is the kindest time to do it.

Choosing the right spring moment

The ideal window in most parts of the UK runs from late March to mid-April, just as the new shoots push through and reach roughly 5cm. The soil is warming, the plant is growing actively enough to heal and re-root quickly, but it has not yet poured energy into flowering. A second, slightly riskier window opens in early September, though divisions made then have less time to settle before cold weather.

What you want to avoid is dividing during or immediately after flowering in June and July, when the plant is under strain and the foliage is at its least resilient. Wait until the flowers have finished and the leaves have been cut back, then leave it until the following spring.

Pick a dull, damp day if you can. Bright sun and drying wind are the enemy of bare roots, so having everything ready before you lift the plant matters more than the calendar.

Lifting the clump without damage

Water the clump thoroughly the day before. Moist soil holds together around the roots and makes the whole operation far less brutal.

• Slide a border fork vertically into the soil about 15cm out from the edge of the clump, then lever gently. Work your way around rather than forcing from one side.
• Lift the whole rootball onto a tarpaulin or old compost sack, keeping as much soil around the roots as possible.
• Shake off the worst of the soil with your hands. If the clump is heavy and solid, a firm tap or two on the ground will loosen it.
• Rinse the rootball with a watering can or dip it in a bucket. Clean roots are much easier to read, and you can see exactly where the natural divisions lie.

If the clump refuses to budge, it has probably been in place for many years. In that case, dig a wider circle and accept that you will lose a few outer bulbs.

Teasing apart and selecting the best sections

Chives divide naturally into little clusters of bulbs joined by a fibrous root mass. Go in with two hand forks back to back, pushing them into the centre and levering apart. For stubborn clumps, an old bread knife or a sharp spade works well, but cut decisively rather than sawing away at the roots.

The centre of an old clump is usually woody, pale and hollow, with the strongest bulbs around the outside. Discard that tired middle on the compost heap and keep the healthy outer sections.

Aim for divisions about the size of your cupped hand, each holding roughly 10 to 15 firm bulbs. Smaller pieces recover faster and give you more plants; larger pieces crop sooner but crowd again quickly. Tidy any damaged roots with secateurs and trim the leaves back to about 5cm, which reduces moisture loss while the roots re-establish.

Unlike ferns, which resent root disturbance and are best divided only when genuinely necessary, chives positively relish being pulled apart. Handle fern crowns with caution and chives with confidence.

Replanting with compost and the right spacing

Prepare the new planting spot before the divisions come out of the ground, so roots are never left sitting exposed. Fork the soil over, remove weeds and add a generous bucketful of garden compost per square metre, plus a handful of blood, fish and bone raked into the top 10cm.

• Set each division in a hole wide enough to take the roots spread out, not bunched.
• Plant at the same depth the bulbs were growing before, so the bulb tops sit just at or fractionally below the soil surface. Planting too deep is the most common reason divisions sulk.
• Space clumps 20 to 25cm apart, allowing air to move between them.
• Firm gently with your knuckles, then water in well and mulch lightly with compost, keeping it clear of the stems.

Aftercare, pots and cottage-garden uses

Water the new clumps regularly for the first three weeks, especially in a dry spring, and keep them weed-free while they settle. You can start snipping lightly once the leaves reach 15cm, but leave the plant alone for its first full season if you want it to build real strength. A liquid seaweed feed every fortnight through May and June encourages plenty of fresh leaf.

Spare divisions are excellent in pots. Use a loam-based compost with added grit for drainage, plant three or four bulbs per 20cm pot and stand them on a sunny windowsill or patio. They will crop through summer and can be moved into the ground in autumn.

In a cottage-style border, use the new clumps to edge paths, tuck around lavender, catmint and hardy geraniums, or fill gaps between roses. The flowers bring pollinators, the leaves bring flavour, and a divided clump will give you both for another three or four years before it needs lifting again.