Crassula helmsii

RHS Plant Profile

New Zealand pigmyweed

RHS

Other common names

Australian swamp stonecrop, New Zealand pygmy weed

Synonyms

Crassula recurva

Aquatic

This plant is listed on Schedule 9 of the UK Wildlife & Countryside Act as an invasive, non-native species and is banned from sale. See cultivation notes for further details A pond weed with trailing stems, small, succulent leaves, and small, whitish flowers. It grows in wet mud beside water, or floats on the surfaceforming dense mats up to 3m deep

Position

Full sun

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Poorly–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–facing or East–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): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Crassulaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Matforming
Genus: Crassula can be succulent annuals, perennials, evergreen shrubs or sub-shrubs, with fleshy leaves and small, star-shaped or funnel-shaped flowers in a terminal cluster
Name Status: Correct

How to Grow

Cultivation

This plant is listed on Schedule 9 of the UK Wildlife & Countryside Act as an invasive non-native species. Across the EU, UK and NI it is an offence to plant or cause to grow in the wild plants listed on Schedule 9 of this order. These plants should not be planted or caused to grow in the wild and in addition are banned from sale. Gardeners possessing them should undertake measures to control them. See RHS advice on invasive non-native species for further information

Propagation

Spreads through broken stem fragments; seeds are produced but are not thought to be viable. See cultivation notes