Repotting guide

When & how to repot Hardy Geranium 'Rozanne' (Geranium 'Rozanne')

Also called Rozanne cranesbill, Gerwat Rozanne.

More about hardy geranium 'rozanne'

About Hardy Geranium 'Rozanne'

Geranium 'Rozanne' · also called Rozanne cranesbill, Gerwat Rozanne · flowering

Geranium 'Rozanne' is an award-winning hardy cranesbill famous for an exceptionally long season of large violet-blue, white-eyed flowers from early summer to autumn frost. It forms a spreading mound of marbled green leaves, weaves through borders and containers, and asks only for sun to part shade and decent drainage. A near-effortless, sterile, ground-covering perennial.

Mature size: Around 50 cm tall and 60-90 cm wide, reaching full spread in 1-2 seasons.

Watch for — Mid-season sprawl and bare centre: After the first flush the mound can open up and look tired. Shear the whole plant back by about a third in midsummer to trigger a fresh, compact flush of foliage and flower.

How to tell hardy geranium 'rozanne' needs repotting

Repotting on a calendar is less reliable than reading the plant. For hardy geranium 'rozanne', 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 hardy geranium 'rozanne') 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 hardy geranium 'rozanne'

Only every 2–4 years, when genuinely crowded. Hardy Geranium 'Rozanne' 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. Mound-forming, sprawling herbaceous perennial that spreads by trailing stems rather than aggressive runners, weaving 60-90 cm wide through neighbouring plants. Sterile, so it flowers continuously without setting seed..

What size pot to step hardy geranium 'rozanne' up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Hardy Geranium 'Rozanne' 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 hardy geranium 'rozanne' 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 hardy geranium 'rozanne'

Early spring, just as new growth restarts, is the ideal window for hardy geranium 'rozanne'. 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 hardy geranium 'rozanne'

Confirm it actually needs it. Slide hardy geranium 'rozanne' 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 hardy geranium 'rozanne' 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 fertile, moisture-retentive but well-drained loam, 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 hardy geranium 'rozanne' 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 hardy geranium 'rozanne'

Hardy Geranium 'Rozanne' wants fertile, moisture-retentive but well-drained loam. Thrives in most ordinary garden soils with good drainage, from slightly acidic to slightly alkaline. Enrich poor ground with compost. Avoid heavy, waterlogged soil over winter, which can rot the crown. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting hardy geranium 'rozanne' — frequently asked questions

How often should you repot hardy geranium 'rozanne'?

Only every 2–4 years, when genuinely crowded for hardy geranium 'rozanne'. Only repot hardy geranium 'rozanne' 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 fertile, moisture-retentive but well-drained loam. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does hardy geranium 'rozanne' need?

When is the best time of year to repot hardy geranium 'rozanne'?

Does hardy geranium 'rozanne' like to be root-bound?

Yes — hardy geranium 'rozanne' 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 hardy geranium 'rozanne' after repotting?

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