Golden barrel cactus

Sun

Full sun to light shade; provide some afternoon shade in exceptionally hot climates. Acclimatise indoor-grown plants gradually before exposing them to direct outdoor sun.

Water

Low once established. Water thoroughly during active growth, then let the root zone dry completely; keep almost dry in winter, especially in cool conditions.

Soil

Very freely draining, gritty soil or cactus compost with added pumice or grit. Avoid heavy clay, waterlogged sites and pots without drainage holes.

Height

2-3 ft (0.6-0.9 m), occasionally taller in very old plants

Spread

2-3 ft (0.6-0.9 m)

Flowers

Small yellow flowers form around the woolly crown in summer, usually only on large, mature plants receiving strong light.

Foliage

No visible leaves; the evergreen green stem has prominent ribs, dense golden spines and a woolly crown. Older plants may become short columns rather than perfect spheres.

Growth

Slow

Care needed

Low

• Water the soil rather than the crown, and empty any saucer after watering.
• Feed container plants once or twice in spring and summer with a dilute cactus fertiliser; do not feed in winter.
• Use a thin gravel mulch if wanted, keeping the stem base clear of damp organic mulch.
• Protect from frost and prolonged winter rain; in the UK and most of Canada, overwinter in a bright, frost-free greenhouse or conservatory.
• Repot only when crowded, using a stable pot with drainage holes and a folded towel or specialist cactus tongs to handle the plant.

Pruning. No routine pruning is needed, and cutting the crown permanently damages its shape. Remove only dead material or diseased tissue with clean tools, protecting your hands and arms from the spines.

Early spring

Check the stem base and roots for rot, inspect for mealybugs, and repot only if the container is crowded.

Spring

Resume watering gradually as growth starts, and give a dilute cactus feed.

Late spring

Move overwintered plants outdoors only after frost risk has passed; increase sun exposure gradually over several weeks.

Summer

Water deeply when the root zone has dried completely, and check pots more often during hot weather.

Autumn

Stop feeding, reduce watering and move tender container plants under bright cover before cold nights.

Winter

Keep cool plants almost dry, maintain ventilation and prevent rain from repeatedly soaking outdoor specimens.

• Repeat rounded specimens through a gravel bed to create a clear rhythm among rocks and upright succulents.
• Use a single mature plant in a broad, stable container as a focal point on a sunny terrace.
• Pair with agaves and fine-leaved grasses in a dry-climate planting for contrasting shapes and textures.
• Group several sizes in a raised, sharply drained bed, well away from paths, seating and children's play areas.

Garden styles it suits: Desert modern, Architectural minimal, Desert / xeriscape, Dry gravel garden, Southwestern and Modern Mediterranean.

Plant it with: Queen Victoria agave, Red yucca, Blue grama, Upright myrtle spurge and Desert spoon.

Wildlife: Flowers can provide pollen and nectar for bees where mature plants bloom. Its spines are a hazard near areas used by pets and people.

• Root or stem rot: soft, discoloured tissue usually follows wet soil or cold, damp conditions. Stop watering, inspect the roots and remove rotten tissue; discard plants with extensive rot.
• Mealybugs: white cottony clusters may hide between ribs or around roots. Isolate the plant and use a treatment labelled for mealybugs on cacti, following the directions.
• Sun scorch: pale or brown patches develop after sudden exposure to strong sun. Provide temporary shade and increase exposure gradually; existing scars remain.
• Frost damage: translucent or blackened tissue follows freezing conditions. Move containers under frost-free cover and keep damaged plants dry while assessing recovery.

Not known to be toxic to people, cats, dogs or horses; no part is generally recognised as poisonous. The sharp spines are the main danger and can cause painful punctures, embedded fragments and eye injuries. Keep it out of reach of children and animals.

• Blue barrel cactus (Ferocactus glaucescens)

  Has a distinctly blue-grey body, generally fewer ribs and more widely spaced golden spines, leaving more of the stem visible.

• Mexican fire barrel (Ferocactus pilosus)

  Usually has conspicuous red central spines, often mixed with white bristles, and becomes taller and more columnar.

• Giant barrel cactus (Echinocactus platyacanthus)

  Develops a much larger, often grey-green body with stout grey or brown spines rather than a dense golden covering; mature plants have a broad woolly crown.

Echinocactus means 'hedgehog cactus', grusonii honours the German cactus collector Hermann Gruson, and 'golden barrel' describes its rounded shape and yellow spines.

Propagation. Usually grown from seed sown in a warm, bright place in a free-draining seed mix. Keep seedlings lightly moist rather than waterlogged. Offsets are uncommon but can be detached if present; allow the wound to callus before placing them in dry cactus mix.

Accepted botanical name

Kroenleinia grusonii Echinocactus grusonii is an older name for Kroenleinia grusonii.

Native range

Mexico Northeast.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.