Repotting guide

When & how to repot Geranium sanguineum (Geranium sanguineum)

Also called Bloody cranesbill.

More about geranium sanguineum

About Geranium sanguineum

Geranium sanguineum · also called Bloody cranesbill · flowering

Geranium sanguineum, bloody cranesbill, is a tough, compact hardy geranium forming a dense mound of deeply cut dark-green leaves studded with magenta-pink, saucer-shaped flowers through summer. Its foliage often reddens in autumn. Drought-tolerant once established and happy in poor, well-drained soil, it makes excellent low ground cover for sunny banks and edges.

Mature size: 20-30 cm tall and 30-45 cm wide, forming a tidy dome within 1-2 seasons.

Watch for — Crown rot in wet ground: Waterlogged or heavy clay soil rots the rootstock over winter. Improve drainage with grit, plant slightly proud, and never let it sit wet.

How to tell geranium sanguineum needs repotting

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

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for geranium sanguineum) flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

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 geranium sanguineum

Only every 2–4 years, when genuinely crowded. Geranium sanguineum is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Compact, mound- to mat-forming herbaceous perennial spreading slowly by rhizomes to make weed-suppressing ground cover, with wiry stems and finely dissected foliage that colours red in autumn..

What size pot to step geranium sanguineum up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Geranium sanguineum positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping geranium sanguineum into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

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 geranium sanguineum

Early spring, just as new growth restarts, is the ideal window for geranium sanguineum. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting geranium sanguineum

Confirm it actually needs it. Slide geranium sanguineum out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip geranium sanguineum out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh well-drained, low-to-average fertility loam, sand or chalk, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water geranium sanguineum again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for geranium sanguineum

Geranium sanguineum wants well-drained, low-to-average fertility loam, sand or chalk. Thrives in light, free-draining soils and tolerates poor, stony and chalky ground at neutral to alkaline pH. Avoid heavy, wet clay; if needed, add grit to improve drainage. Lean soil keeps the mound tight and floriferous. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting geranium sanguineum — frequently asked questions

How often should you repot geranium sanguineum?

Only every 2–4 years, when genuinely crowded for geranium sanguineum. Only repot geranium sanguineum every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using well-drained, low-to-average fertility loam, sand or chalk. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does geranium sanguineum need?

When is the best time of year to repot geranium sanguineum?

Does geranium sanguineum like to be root-bound?

Yes — geranium sanguineum genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise geranium sanguineum after repotting?

Not immediately. Wait about 4 weeks after repotting geranium sanguineum. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.