Repotting guide

When & how to repot Long-Stalked Cranesbill (Geranium columbinum)

Also called Long-Stalked Cranesbill, Longstalk Cranesbill.

More about long-stalked cranesbill

About Long-Stalked Cranesbill

Geranium columbinum · also called Long-Stalked Cranesbill, Longstalk Cranesbill · flowering

Geranium columbinum is a slender, wiry-stemmed annual native to the UK and much of Europe, western Asia and North Africa, favouring dry calcareous grassland, hedgebanks, cliff slopes and field margins from lowland up to around 1,200 m. Its deeply cut, finely divided leaves and small pink to purple flowers appear from April to September, carried on distinctively long, slender pedicels that give the species its name. It requires well-drained, preferably calcareous soils in a warm, sunny position and dislikes wet or shaded conditions. True cranesbill Geranium species are not listed as toxic to pets by the ASPCA, and this species is considered non-toxic to cats and dogs.

Mature size: 15–45 cm tall, spreading to 25 cm

How to tell long-stalked cranesbill needs repotting

Repotting on a calendar is less reliable than reading the plant. For long-stalked cranesbill, watch for these signs:

Roots circling the bottom of the module or pot, or poking out of the drainage holes.
The seedling dries out within a day and growth has visibly stalled.
Roots are white and matted in a tight spiral when you tip the plant out.
It has outgrown its current container for the stage of the season — pot long-stalked cranesbill on before it becomes hard root-bound.

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 long-stalked cranesbill

Pot on seedlings as they grow; not a perennial repot. Long-Stalked Cranesbillis grown for one season, so the question is really “how often to pot on” — keep moving it up before the roots circle. Erect to scrambling annual with finely dissected, deeply cut leaves and distinctively long flower stalks (pedicels); branching and somewhat straggling when mature..

What size pot to step long-stalked cranesbill up to

Pot long-stalked cranesbill on gradually — a seedling jumped straight into a huge pot sits in cold, wet, airless soil and stalls. Step up one or two sizes at a time as the roots fill each container, finishing in a large final pot or the ground. The aim is roots that never circle and never check.

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 long-stalked cranesbill

Pot long-stalked cranesbill on through the active growing season, whenever roots fill the current container — there is no single date, just "before it becomes root-bound". Avoid potting on during a cold snap.

Step-by-step: repotting long-stalked cranesbill

Pot on before it is root-bound. Check long-stalked cranesbill regularly; move it up as soon as roots reach the edge of the cell or pot, not after they have circled.
Step up one or two sizes. Choose the next container up — not a giant one. Cold, wet, unused soil around a small root system stalls seedlings.
Knock it out gently. Support the stem, tip the pot, and ease the rootball out without breaking it. A little teasing of circled roots at the base is fine.
Pot into rich mix. Set it into fresh free-draining, preferably calcareous (chalky or limestone) loam or sandy soil; neutral to alkaline ph at the same depth (tomatoes are the exception — they can go deeper to root along the stem).
Water in and grow on. Water well, keep it in good light, and resume feeding once it is established and growing again.

Aftercare

Water long-stalked cranesbill in well and keep it in bright light; a freshly potted-on seedling can wilt for a day while roots settle, so do not overcompensate by drowning it. Do not fertilise for about 1 week — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for long-stalked cranesbill

Long-Stalked Cranesbill wants free-draining, preferably calcareous (chalky or limestone) loam or sandy soil; neutral to alkaline ph. Best on well-drained chalk, limestone or gravelly soils with moderate to low fertility. Can pioneer on disturbed bare ground. Avoid heavy clay and waterlogged conditions. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting long-stalked cranesbill — frequently asked questions

How often should you repot long-stalked cranesbill?

Pot on seedlings as they grow; not a perennial repot for long-stalked cranesbill. Long-Stalked Cranesbill is a seasonal crop, so you pot it on as a growing plant rather than repotting a perennial. Step seedlings up gradually into free-draining, preferably calcareous (chalky or limestone) loam or sandy soil; neutral to alkaline ph so the roots never circle the cell, ending in a large final container. A root-bound transplant stalls and never fully recovers.

What size pot does long-stalked cranesbill need?

When is the best time of year to repot long-stalked cranesbill?

Can you put long-stalked cranesbill straight into a much bigger pot?

No. Even a fast-growing long-stalked cranesbill should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise long-stalked cranesbill after repotting?

Not immediately. Wait about 1 week after repotting long-stalked cranesbill. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.