Species · genus Euphorbia · Euphorbiaceae

Thornless Crown Of Thorns

Euphorbia geroldii Rauh

Growth habit

semisucculent shrub

Native range

Madagascar

Reference · E. geroldii

Cultivars of E. geroldii

The named forms growers keep — each with its own page, each honest about how much we know.

No named cultivars catalogued under E. geroldii yet. When growers document a stable, named form, it earns its own page here.

Guide

The species-level account. Cultivar pages build on this and say where they differ.

A semisucculent shrub from Madagascar, Euphorbia geroldii stores moisture in its stems and wants gritty, fast-draining mix with strong light. Water deeply only when the top two inches of mix are fully dry, letting it approach dryness between drinks; standing wet causes rot. It tolerates dry indoor air and benefits from bright direct sun.

Care recipe

The species record — the baseline every cultivar inherits unless it says otherwise.

Care notes are early — not yet verified

Light: ai:claude-opus-4-8
Water: ai:claude-opus-4-8 (range 10-21d)
Humidity: ai:claude-opus-4-8
Soil: ai:claude-fable-5
Care: ai:claude-fable-5

Light

Direct sun

Water

≈ every 21 days

Humidity

Low — average room

Temperature

15–30 °C

Soil mix

Gritty, fast-draining succulent mix

Propagation

Stem cuttings, callused before rooting

Fertilizing

Dilute balanced feed monthly in the growing season

Growth rate

Moderate

Flowering

Repeat-blooming red bracts in good light, thornless stems

ToxicityAuthoritative · species

Toxic to cats & dogs & humans

Euphorbiaceae exude an irritant milky latex that can harm skin, eyes, and mucous membranes if ingested or handled. This is where toxicity lives: every cultivar of this species inherits it and none can override it.

Reference images

Every image credited. Licenses link to their deeds.

No reference gallery yet

A few clear photos — habit, a mature leaf, a flower if it blooms — would give this page its eyes.

Add images

Sources: ai:claude-opus-4-8 · ai:claude-opus-4-8 (range 10-21d) · ai:claude-fable-5 · ai:claude-opus-4-8 (family inference)

Kept true by its growers

Every fact here carries its source. Grow Thornless Crown Of Thorns yourself? What you’ve observed — how it drinks, how it holds its color, a name that’s off — is exactly what keeps this page honest. Contributions are reviewed before anything changes.