Acer negundo subsp. californicum var. texanum

RHS Plant Profile

Californian box elder

Synonyms

Acer negundo var. texanum

Trees

Fast-growing, deciduous, bushy tree to about 15m tall, with soft, hairy, pinnate bright green leaves composed of 3 leaflets, turning yellow in autumn. Greenish-yellow flowers in racemes, are produced in spring, male and female flowers on separate trees, the flowers on male trees with showy pink tassels; then brown winged fruits follow

Position

Full sun, Partial shade

Soil Types

Clay, Sand, Loam

Max Height

Higher than 12 metres

Max Spread

2.5-4 metres

Size

Time to Maturity: 10–20 years
Max Spread: 2.5-4 metres
Max Height: Higher than 12 metres

Growing Conditions

Clay Sand Loam

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or North–facing or South–facing or West–facing
Exposure: Exposed or 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): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Sapindaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Bushy
Genus: Acer can be deciduous trees or large shrubs with paired, often palmately-lobed leaves and small flowers followed by characteristic winged fruits. Many have fine autumn colour, and some have ornamental stems
Name Status: Correct
Plant Range: S. USA

How to Grow

Cultivation

Grow in fertile, moist but well-drained soil in sun or partial shade. See tree cultivation for further advice

Propagation

Propagate by seed (trees and shrubs), layering in autumn, grafting in late winter or softwood cuttings in early summer

Suggested planting locations and garden types

Cottage and informal garden
Wildlife gardens

Pruning

Pruning group 1 from late autumn to midwinter only

Pests

May be susceptible to Acer gall mite, aphids, caterpillars and horse chestnut scale

Diseases

May be susceptible to Verticillium wilt, Acer leaf scorch and honey fungus