How to Overwinter Geraniums (Pelargoniums)

The bedding 'geraniums' blazing away in pots and window boxes right now are actually pelargoniums — tender perennials from South Africa. Frost kills them, but there's no need to bin them in autumn and buy new ones next year: a plant you overwinter keeps its size and flowers earlier next summer, and favourite varieties are preserved for free. Late summer is exactly the moment to plan, because the best method — cuttings — works best while plants are still in active growth.

Know your plant (and your deadline)

True hardy geraniums (cranesbills) survive winter in the ground and need none of this. Everything below applies to pelargoniums: zonal and ivy-leaved pelargoniums, regals, and scented-leaf types. The deadline is your first frost. Even one light frost damages them, so act while nights are still above roughly 5°C — in most temperate gardens that means having a plan by September and everything indoors before mid-autumn.

Method 1: bring them in as houseplants

The simplest option if you have a bright, cool windowsill. Before frost, dig up garden plants (or just carry pots in), check for pests, and cut the plants back by a third to a half. Pot into fresh, free-draining compost, set them in your sunniest window, and keep them cool — around 10–18°C is ideal; a heated living room at 22°C tends to produce pale, leggy growth. Water only when the top few centimetres of compost are dry. Pinch leggy shoots back above a leaf node through winter to keep plants bushy, and don't feed until late winter.

Method 2: take cuttings in late summer

Cuttings are the classic insurance policy, and August into early September is prime time because the parent plant is still growing strongly. Young plants also overwinter on a windowsill in less space than one big parent.

• Cut 8–10 cm non-flowering shoot tips just below a node, using a clean, sharp knife.
• Strip the lower leaves and any flower buds, leaving two or three leaves at the top.
• Push the cuttings into pots of gritty, free-draining compost (a half-and-half mix with perlite or sharp sand is ideal). Rooting hormone helps but isn't essential — pelargoniums root willingly.
• Keep them in bright light, out of direct midday sun, and on the dry side of moist. Do not cover pelargonium cuttings with a plastic bag — trapped humidity rots them.
• Expect roots in roughly four to six weeks; pot rooted cuttings individually and grow them on cool and bright until spring.

Method 3: bare-root dormant storage

The old-fashioned space-saver, done in cellars for generations: before frost, dig up whole plants, shake the soil off the roots, and let them dry for a few days. Store them somewhere dark, frost-free and cool — 7–13°C is the sweet spot — either hung upside down, or loosely wrapped in newspaper or open paper bags. The leaves will dry up and drop; that's expected. Check monthly: soak the roots in water for an hour or two once or twice over winter if the stems start shrivelling badly, and throw out anything soft or mouldy. Success rates are lower than the other two methods, but so is the effort — and it needs no light at all.

Waking them up in spring

In late winter to early spring, cut overwintered plants back to 10–15 cm, pot bare-root plants into fresh compost, move everything somewhere bright and slightly warmer, and resume normal watering. New shoots appear within a few weeks; start feeding fortnightly once they do. Harden plants off gradually and move them outside only after your last frost.

Tip: label every plant and cutting with the variety name in autumn. By March, one leafless pelargonium stump looks exactly like another.

Warning: the single biggest killer of overwintering geraniums is winter overwatering. A cool, semi-dormant pelargonium may need water only every three to four weeks. When in doubt, keep it dry — a wilted plant recovers, a rotted one doesn't.

If an overwintering plant starts looking sick — yellowing leaves, spots, mystery droop — photograph it in PlantMe. The app recognises 500+ plant diseases and problems and tells you whether you're looking at rot, rust, or just normal winter sulking.