Golden Barrel Cactus
Echinocactus grusonii · Mother-in-law's Cushion
It grows on sunny volcanic slopes in east-central Mexico, a slow spherical barrel ribbed and armoured with golden spines. You can buy it by the million in any garden centre, yet in the wild it is officially Endangered.
Family
Cactaceae
Origin
East-central Mexico
In the wild
Volcanic slopes
Indoors
15–40 cm
Growth
Slow
With pets
Non-toxic
Where it's from
Queretaro and Hidalgo, Mexico
A single valley
Endemic to Queretaro and Hidalgo, around the Moctezuma River valley, on well-aerated volcanic ground.
Outdoors: zones 9–11
Nearly frost-free. It tolerates brief dips but is not reliably frost-hardy.
Roughly 11,000 left
The wild population is estimated at about 11,000 mature plants and decreasing, severely fragmented.
Common yet Endangered
Nurseries grow it from seed by the million for dish gardens and xeriscapes. Yet in 1994 the Zimapan Dam reservoir flooded most of its wild home in central Mexico in one stroke, and the survivors are still poached from the slopes. The pot on your shelf is safe. The wild plant is not.
Drowned by a dam
The 1994 Zimapan Dam reservoir flooded much of its Moctezuma-valley range.
Still poached
Wild plants are stripped from the slopes for the horticultural trade.
Seed-grown millions
Largely solitary, so the commercial supply runs on seed, not offsets.
How to keep it
LightFull sun
The brightest possible window. It needs strong light to keep colour and eventually flower.
WaterSoak and dry
Sparing in the growing season, minimal in winter. Pooling water causes root rot. Drainage is the key factor.
HumidityDry air is fineTolerates dry indoor air. No misting.
TemperatureAbove 12°CKeep above an average winter minimum of about 12°C. Not reliably frost-hardy.
SoilGritty cactus mixFast-draining and gritty, mimicking well-aerated volcanic ground.
FeedingLight, in growthA light feed in the growing season only. Little is needed.
DifficultyEasyOne of the most forgiving cacti, and a relatively fast grower for a barrel in warmth.
With petsNon-toxicNot chemically toxic. The hazard is mechanical: the stiff spines can puncture mouths and paws.
PropagationMostly seedLargely solitary, so it is grown from seed. Basal pups, when they form, can be separated.
RepottingEvery few yearsInfrequent, when rootbound. Mind the spines.
What the data says
What it costs
A mass-propagated commodity. Spine-colour forms carry a small premium, but there is no collector bubble.
$8–30
White-spined, blue and short-spined forms run $30 to $100 or more by size. Large old specimens cost much more.
IUCN · Endangered
In the wild
A species you can buy by the million is at the same time Endangered in nature.
NaN+mature plants left in the wild, and decreasing, severely fragmented (IUCN, 2009).
All Cactaceae are CITES Appendix II, so wild collection needs permits even though nursery stock is everywhere. Drowned by a dam, still poached, yet sold endlessly.
When it sulks
Soft, mushy, discoloured baseRoot rot from overwatering or poor drainage. The number one killer.
Pale, elongating instead of roundToo little light.
Scarring or corky marksSunburn after a sudden move to intense sun, or cold damage.
No flowers indoorsNormal. It needs great age and very strong light to bloom.
PestsMealybugs, scale and red spider mites are the usual cactus offenders.
Varieties & company
The varieties
Golden BarrelWhite-spined formShort-spined formBlue Barrel
Pairs with · keep apart from
AgaveEcheveriaSnake PlantMonsteraFernsCalathea
A new plant, every week.
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