Autumn is not the end of the herb gardening year – it is the beginning of the next one. As the light fades and the first hard frost creeps closer, the jobs you do now will determine how vigorously your chives, mint, rosemary and thyme bounce back in spring. The soil is still warm, the air is crisp, and there is just enough time to divide, cut back, mulch and shelter before winter tightens its grip. Here is a practical guide to getting it right in a UK garden, whether you grow herbs in borders, raised beds or pots on a sheltered patio.

Why autumn work pays off in the herb garden

Herbs are tough, but they are not indestructible. A wet UK winter followed by a sharp frost can waterlog roots, heave crowns out of the soil and kill tender plants that would otherwise sail through. The secret is to act while the ground is still workable and the plants are winding down rather than completely dormant. Timing matters: aim to finish these jobs by late October in most parts of the country, or early November in milder coastal areas. If you garden in a cold pocket – a frost hollow or exposed northern plot – bring everything forward by a fortnight.

Divide chives and other clump-forming herbs

Chives are the classic herb to divide in autumn. After two or three years, a clump becomes congested, with weak, thin leaves and fewer flowers. Lifting and splitting it now gives you vigorous new plants for free – and it is far less stressful for the herb than dividing in spring.

Water the clump the day before. Then use a garden fork to lift it gently, keeping as much root as possible. Shake off excess soil and tease the bulbs apart with your hands or two forks back to back. Replant healthy sections in groups of four to six bulbs, about 15cm apart and 5cm deep. Water them in well. The same technique works for mint (though it rarely needs encouragement), lemon balm, oregano and marjoram. Always replant into soil enriched with garden compost – they will reward you with lush growth next year.

Cut back spent stems – but choose wisely

Not all herbs want the same autumn treatment. Soft, leafy herbs such as mint, chives, lemon balm and parsley can be cut back hard after flowering – to about 5cm from the base – to encourage a final flush of fresh leaves before dormancy. Leave a few seedheads on fennel, dill and coriander for the birds and for self-seeding.

Woody herbs are a different story. Never cut rosemary, sage, thyme or lavender back into old, leafless wood in autumn; they may not regrow. Instead, give them a light trim to tidy straggly stems and remove dead flower spikes. Save any hard pruning for spring, once new growth appears. Basil, tender and annual, will not survive a frost – harvest the leaves now, or take softwood cuttings to root on a warm windowsill.

Mulch tender plants and protect vulnerable roots

Mulching is the single best way to insulate herb roots against freeze-thaw cycles. Wait until the soil has cooled but is still moist – usually mid to late autumn – then spread a 5–8cm layer of well-rotted compost, leaf mould or bark chippings around the base of tender perennials such as rosemary, bay, myrtle and lemon verbena. Keep the mulch clear of stems to avoid rotting them off.

In colder areas, add a loose layer of straw or bracken over the crown of borderline-hardy herbs like French tarragon and thyme. For herbs growing in borders, a cloche or a double layer of horticultural fleece will keep the worst of the frost off. Do not mulch dry, frozen ground – it traps cold and does more harm than good.

Move pots under cover before the first hard frost

Herbs in containers are far more exposed than those in the ground. Their roots can freeze solid, and the pots themselves may crack. Before the first hard frost arrives, move pots of rosemary, bay, lemon verbena, scented geraniums and other tender herbs into a greenhouse, cold frame, conservatory or a bright porch. If you have no indoor space, group them together against a south-facing house wall and wrap the pots in bubble wrap or hessian.

Raise pots onto feet or bricks so they never sit in a puddle. Reduce watering – damp cold is deadlier than dry cold – but do not let the compost shrivel completely. Check them fortnightly and water sparingly on mild days. Hardy herbs like mint, chives and oregano can stay outside, but move them to a sheltered spot and consider wrapping the pots for extra insurance.

A final tidy and a few winter rewards

Finish with a gentle clean-up. Remove fallen leaves and dead plant debris from around your herbs to deny slugs, snails and fungal diseases a winter home. Harvest any remaining leaves of thyme, sage, rosemary and parsley – they dry beautifully or freeze in ice-cube trays with a little water. Take semi-ripe cuttings of rosemary, sage and thyme now; they root readily in a cold frame and give you replacements for any winter losses.

Finally, resist the urge to cut everything down to the ground. A little untidiness – hollow stems, seedheads, a few evergreen leaves – provides shelter for beneficial insects and structure for frosty mornings. Your herbs will thank you, and so will the birds. Come spring, you will have a garden that leaps back into life rather than one that struggles to recover.