Echinocactus grusonii

Source: Own work | CC BY 4.0

Echinocactus grusonii
Kew Gardens

Echinocactus grusonii or golden barrel cactus is a very striking spherical cactus.

Though it is very popular and easy to grow, it is seriously threatened by habitat loss and harvest.

Growth is very slow.

Description:

Echinocactus grusonii is a spherical, later elongated, cactus that grows up to 1 m in diameter.

It has 21-37 ribs, the spines are yellow to white. The 8-10 radial spines are up to 3.2 cm long, with 4 central spines up to 5 cm long.

Flowering takes place in late spring to early summer on older specimens (it may take up to 20 years before flowering begins). The flowers are yellow, up to 6.5 cm long.

Nomenclature:

Common names:

Golden barrel cactus, golden ball, mother-in-law’s cushion

Synonyms:

Echinocactus corynacanthus, Echinocactus galeottii

Etymology:

Echinocactus: from the Greek ekhînos (hedgehog, sea urchin) and káktos (cardoon)
Grusonii: to Hermann Gruson, a 19th century German cactophile

Origin:

Central Mexico

Habitat:

Semi-desert matorral (Spanish word for shrubland, thicket or bushes), among volcanic rocks or calcareous soil on medium to steep slopes, at altitudes around 1,400 m

Hardiness:

USDA zones 9-12

Care:

Soil:

Cactus mixture with a layer of pebbles or gravel at the bottom of the pot for good drainage

Exposure:

Sun

Water:

Water regularly from spring to autumn when the soil starts to dry out, sparingly in winter. Too much water at lower temperatures causes root rot.

Fertilizer:

Fertilize monthly with a specialized cactus fertilizer

Repotting:

Repot young plants annually, older plants every 2-3 years

Remarks:

  • always use gloves when handling a cactus
  • for repotting fold up a few sheets of newspaper into a thick flat band. Surround the cactus with this band handle him
  • remove the spines from the skin by applying a patch of adhesive tape and removing it

Propagation:

Seed

Sowing instructions:

  • use a mix of topsoil, sand and gravel (1:1:1) and sterilize that (e.g. in the microwave)
  • fill a pot with the mixture and moisten it
  • sow the seeds on the surface and press very lightly
  • place the pot with seeds in a plastic bag and close it
  • place the pot in a bright location out of direct sunlight
  • 20-25°C
  • regularly check that no fungi develop
  • when the seeds begin to germinate make a few holes in the plastic bag and then every week 2-4 additional holes for the seedlings to get used gradually to drier air
  • germination: 3-6 weeks

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