Thelocactus macdowellii

RHS Plant Profile
Chihuahuan snowball

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Cactus Succulent Houseplants

A spherical cactus to 10cm, with conical, warty tubercles each bearing a white wooly areole from which white spines arise. In spring, funnel-shaped pink flowers to 6cm across are borne near the top of the stem

Position

Full sun

Soil Types

Loam, Sand

Max Height

Up to 10 cm

Max Spread

0-0.1 metre

Size

Time to Maturity
5–10 years
Max Spread
0-0.1 metre
Max Height
Up to 10 cm

Growing Conditions

Loam Sand
Moisture
Well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing
Exposure
Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

  • H1A: under glass all year (>15C)
  • H1B: can be grown outside in the summer (10 - 15)
  • H1C: can be grown outside in the summer (5 - 10)
  • H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
  • H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
  • H4: hardy through most of the UK (-10 to -5)
  • H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
  • H6: hardy in all of UK and northern Europe (-20 to -15)
  • H7: hardy in the severest European continental climates (< -20)
H2

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Cactaceae
Native to GB/Ireland
No
Foliage
Evergreen
Habit
Columnar upright
Genus
Thelocactus are cacti with ribbed, spiny, globose or shortly cylindrical stems and large funnel-shaped flowers
Name Status
Correct
Plant Range
N. E. Mexico

How to Grow

Cultivation

Grow in standard cactus compost in full light with low humidity. When in growth, water moderately and apply a low-nitrogen fertiliser monthly; keep dry in winter. See houseplant cacti and succulent cultivation for further information

Propagation

Propagate by seed

Suggested planting locations and garden types

  • Houseplants
  • Sub-tropical
  • Low Maintenance
  • Conservatory and greenhouse

Pruning

No pruning required

Pests

May be susceptible to mealybugs

Diseases

May be susceptible to stem and root rots if overwatered