Repotting guide

When & how to repot Arisaema consanguineum (Arisaema consanguineum)

Also called whiplash cobra lily, Chinese cobra lily.

More about arisaema consanguineum

About Arisaema consanguineum

Arisaema consanguineum · also called whiplash cobra lily, Chinese cobra lily · flowering

Arisaema consanguineum is one of the easier cobra lilies, forming a tall stem topped by a striking umbrella of 11-20 narrow leaflets, often tipped with thread-like whiplash drip-tips. A green-and-white striped, purple-brown hooded spathe appears in early summer. This deciduous Himalayan-Chinese tuber wants cool, humus-rich, dappled shade.

Mature size: Typically 60-120 cm tall and 45-60 cm wide; one of the taller cobra lilies in good soil.

Watch for — Stem flop: The tall pseudostem can lean or topple in exposed sites. Plant in a sheltered, wind-protected spot in deep soil.

How to tell arisaema consanguineum needs repotting

Repotting on a calendar is less reliable than reading the plant. For arisaema consanguineum, 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 arisaema consanguineum 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 arisaema consanguineum

Lift and divide every 3–4 years once clumps congest. Rather than a true repot, arisaema consanguineum is lifted and divided once the clump congests and flowering drops off. Tuberous deciduous perennial with a single tall pseudostem carrying one large umbrella-shaped (radiate) leaf of many leaflets, and a hooded spathe. Dies back to a dormant tuber annually..

What size pot to step arisaema consanguineum up to

Pot size matters less than depth and spacing here. When you replant arisaema consanguineum, 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 arisaema consanguineum

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 arisaema consanguineum in full growth or flower sets it back badly.

Step-by-step: repotting arisaema consanguineum

Wait for dormancy. Let arisaema consanguineum 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 deep, humus-rich, moisture-retentive but well-drained loam 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 arisaema consanguineum, 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 arisaema consanguineum

Arisaema consanguineum wants deep, humus-rich, moisture-retentive but well-drained loam. Enrich with leaf mould and compost; add grit for drainage. Slightly acidic to neutral. The tall stem benefits from a sheltered spot in deep, fertile soil where the tuber can sit dry but not waterlogged in dormancy. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting arisaema consanguineum — frequently asked questions

How often should you repot arisaema consanguineum?

Lift and divide every 3–4 years once clumps congest for arisaema consanguineum. Arisaema consanguineum 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 deep, humus-rich, moisture-retentive but well-drained loam. Crowding, not pot size, is what reduces flowering over time.

What size pot does arisaema consanguineum need?

When is the best time of year to repot arisaema consanguineum?

Do you "repot" arisaema consanguineum, or lift and divide it?

You lift and divide it. Arisaema consanguineum 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 arisaema consanguineum after repotting?

Hold off feeding arisaema consanguineum 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.