Repotting guide

When & how to repot Showy Autumn Crocus (Colchicum speciosum)

Also called Showy autumn crocus, Giant meadow saffron, Showy colchicum.

More about showy autumn crocus

About Showy Autumn Crocus

Colchicum speciosum · also called Showy autumn crocus, Giant meadow saffron · flowering

Showy autumn crocus is a large-flowered cormous perennial native to subalpine meadows of northern Turkey, the Caucasus, and northern Iran, producing impressively large, goblet-shaped flowers up to 12 cm across in shades of rosy-purple to white from August to October. It is the parent of many popular garden colchicum cultivars and is considered one of the finest and most showy of all autumn-flowering bulbs. Plant the large corms during summer dormancy in well-drained soil where the tall flowers will not be obscured by neighbouring plants. All parts of this plant contain colchicine and are extremely toxic to pets and humans.

Mature size: 20–25 cm tall in flower; leaves reach 30–40 cm in spring; clumps spread to 30–40 cm over several years.

How to tell showy autumn crocus needs repotting

Repotting on a calendar is less reliable than reading the plant. For showy autumn crocus, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

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 showy autumn crocus

Every 2–3 years, into bone-dry mix. Showy Autumn Crocus's growth habit — clump-forming cormous perennial with a dramatic naked-flower, spring-leaf cycle; very large, glossy ribbed leaves appear in late winter and last until early summer, followed by leafless flowers in late summer to autumn. — sets the pace. Showy autumn crocus is a large-flowered cormous perennial native to subalpine meadows of northern Turkey, the Caucasus, and northern Iran, producing impressively large, goblet-shaped flowers up to 12 cm across in shades of rosy-purple to white from August to October. It is the parent of many popular garden colchicum cultivars and is considered one of the finest and most showy of all autumn-flowering bulbs. Plant the large corms during summer dormancy in well-drained soil where the tall flowers will not be obscured by neighbouring plants. All parts of this plant contain colchicine and are extremely toxic to pets and humans.

What size pot to step showy autumn crocus up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Showy Autumn Crocus stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

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 showy autumn crocus

Spring or summer, while showy autumn crocus is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting showy autumn crocus

Repot dry. Do not water showy autumn crocus for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty well-drained, moderately fertile loam ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set showy autumn crocus at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep showy autumn crocus completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for showy autumn crocus

Showy Autumn Crocus wants well-drained, moderately fertile loam. Tolerates a range of soils from sandy loam to chalk, provided drainage is sharp; plant the large corms 15 cm deep in prepared, gritty soil in summer to avoid corm rot and support the tall flower stems. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting showy autumn crocus — frequently asked questions

How often should you repot showy autumn crocus?

Every 2–3 years, into bone-dry mix for showy autumn crocus. Repot showy autumn crocus every 2–3 years into a snug pot of well-drained, moderately fertile loam, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does showy autumn crocus need?

When is the best time of year to repot showy autumn crocus?

Should you water showy autumn crocus after repotting?

No — not straight away. Repot showy autumn crocus into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise showy autumn crocus after repotting?

Not immediately. Wait about 3 weeks after repotting showy autumn crocus. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.