Repotting guide

When & how to repot South African Geranium (Pelargonium sidoides)

Also called South African Geranium, Umckaloabo, African Geranium.

More about south african geranium

About South African Geranium

Pelargonium sidoides · also called South African Geranium, Umckaloabo · herb

Pelargonium sidoides is a tuberous-rooted perennial species from the dry grasslands and rocky slopes of South Africa, valued both as an ornamental and as a medicinal herb — its root extract is the basis for Umckaloabo, a widely sold herbal cold and bronchitis remedy. It produces a low, velvety-silver rosette of heart-shaped leaves and abundant small, deep maroon-to-black flowers on upright stems throughout a long season. It needs very free-draining soil and dislikes wet winters, making container culture the safest approach in UK and northern US gardens. Toxic to cats and dogs.

Mature size: 20-35 cm tall in flower; rosette 20-30 cm wide

Watch for — Root and stem rot: The most common cause of death in wet or heavy soils; stems blacken at the base and collapse. Always use very gritty compost, ensure pots drain freely, and keep the plant nearly dry in winter.

How to tell south african geranium needs repotting

Repotting on a calendar is less reliable than reading the plant. For south african geranium, watch for these signs:

Flowering has tailed off year on year and the clump has become congested and overcrowded.
Lots of leaf and few flowers — a classic sign that south african geranium bulbs or tubers need lifting and dividing.
Bulbs visibly bursting the pot or pushing each other to the surface.
It is the natural dormancy window (foliage yellowed and died back) — the only safe time to lift and split.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot south african geranium

Lift and divide every 3–4 years once clumps congest. Rather than a true repot, south african geranium is lifted and divided once the clump congests and flowering drops off. Low-growing, clump-forming tuberous perennial with a basal rosette of softly hairy, silver-green heart-shaped leaves and upright flowering stems 20-40 cm tall..

What size pot to step south african geranium up to

Pot size matters less than depth and spacing here. When you replant south african geranium, set the bulbs or tubers at the correct depth (a rough guide: two to three times their own height of soil over the top) and space them so they are not touching. A wide, shallow pot suits a clump better than a tall narrow one.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot south african geranium

The only safe window is dormancy: wait until the foliage has yellowed and died back naturally, lift and divide then, and replant before or at the start of the next growing season. Disturbing south african geranium in full growth or flower sets it back badly.

Step-by-step: repotting south african geranium

Wait for dormancy. Let south african geranium foliage yellow and die back completely. Lifting while it is in growth wastes the energy it is storing for next year.
Lift carefully. Loosen the soil well away from the bulbs/tubers with a fork and ease the whole clump out without spearing them.
Separate the offsets. Gently pull the clump apart into individual bulbs or tubers. Keep only firm, healthy, blemish-free ones.
Replant at the right depth. Reset them in fresh very free-draining, gritty loam, ph 6.0-7.0 at the correct depth and spacing — not touching — so each has room to bulk up.
Water in and rest. Water once to settle them, then keep on the dry side until growth resumes. Do not feed until leaves are actively growing.

Aftercare

After replanting south african geranium, keep the soil barely moist — not wet — until shoots appear; bulbs and tubers rot in cold, saturated soil. Once leaves are growing strongly, resume normal watering. Hold off feeding until the plant is in active growth again.

The right soil mix for south african geranium

South African Geranium wants very free-draining, gritty loam, ph 6.0-7.0. A loam-based compost with at least 30-40% coarse grit or perlite suits its native rocky grassland habitat. Avoid any peat-heavy or moisture-retentive mixes, which cause root and stem rot. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting south african geranium — frequently asked questions

How often should you repot south african geranium?

Lift and divide every 3–4 years once clumps congest for south african geranium. South African Geranium is lifted and divided, not "repotted". Every 3–4 years, once the foliage has died back and it is dormant, lift the clump, separate the offsets, and replant at the correct depth in very free-draining, gritty loam, ph 6.0-7.0. Crowding, not pot size, is what reduces flowering over time.

What size pot does south african geranium need?

When is the best time of year to repot south african geranium?

Do you "repot" south african geranium, or lift and divide it?

You lift and divide it. South African Geranium grows from bulbs or tubers, so instead of repotting you wait for dormancy, lift the congested clump, separate the healthy offsets, and replant them at the right depth and spacing. Doing this every 3–4 years restores flowering.

Should you fertilise south african geranium after repotting?

Hold off feeding south african geranium until it is in active growth again. Fresh soil already carries enough nutrients to get it re-established, and feeding disturbed roots too soon does more harm than good.