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Scientific: Brachychiton populneus
Common: Australian bottle tree, Kurrajong
Family: Sterculiaceae
Origin: Eastern Australia from northern Victoria into Queensland.

Pronounciation: Brac-ka-CHI-ton po-pul-NAY-us

Hardiness zones
USDA 9-11

Landscape Use: Strong vertical accent, commercial or large residential settings, popular shade tree in grassy urban parks, lawn tree.

Form & Character: Upright and pendulous, conical when young to more spreading with age, combined tropical and alpine character (a weird mix I know).

Growth Habit: Evergreen, woody, broadleaf perennial tree, vigorously upright to 60-feet tall, pyramidal when young but spreading with age. The bottle tree trunk is generally smooth and gray (except where heat stressed) and tends to flare at the base. The main scaffold branches are generally thick and extending upwards, sometimes perpendicular.

Foliage/Texture: Foliage generally light green, entire, ovate to deltoid (aspen like = desirable) or 3 to 5 lobed (turkey track = undesirable), mostly 3-inches long or less; medium texture.

Flowers & Fruits: Clusters of bell-shaped, yellow-green flowers with yellowish red inside on short, axillary panicles (on a stalk), spring time. Fruits are hard, woody canoe-shaped, persistent, then messy.

Seasonal Color: None

Temperature: Tolerant as long as surrounded by vegetation. Suffers heat stress if placed in sites dominated by a lack of vegetation and inorganic surface mulches, i.e., 'desert landscapes'.

Light: Full sun, though hot summer western sun can scald the trunk.

Soil: In Phoenix, bottle trees exhibit foliar interveinal chlorosis in moist lawn soils with pH above 8.0.

Watering: Irrigate bottle trees deeply at least weekly during summer for best results.

Pruning: Elevate canopy base, but avoid western sun exposure on main trunk (sunscald time).

Propagation: Seed; majority of seed lot will germinate with turkey track (3 to 5 lobed) leaf form and minority will have aspen like foliage (ovate to deltoid).

Disease and Pests: Bottle tree is highly susceptible to Phymatotrichopsis (common name, Texas root rot) in former agricultural soils in the Phoenix area. Local Texas root rot symptoms include abrupt leaf browning and tree death usually sometime during July to October (mostly September after soil temperatures exceed 80oF). Bottle tree is also susceptible to local wood pecker damage.

Additional comments: Bottle trees were widely planted in Phoenix during the 1960s to 1980s as a dominant element in mesic and oasis landscapes - oh, how times have changed! Bottle tree fruit pods are resistant to decay, pose a litter problem and can injure bare foot wanderers and reel lawn mowers. Young bottle trees are subject to wind throw especially if their roots have been deformed by prior (mis)culture in nursery containers. Flame Tree (Brachychiton acerifolius) is somewhat taller with red flowers.

Taxonomic musings: The genus Brachychiton contains 31 species of trees and shrubs, all native to Australia (30 species) and New Guinea (one species). Many have odd, bulbous trunks for the storage of water during extended periods of dryness such as this Brachychiton rupestris that I came across in a landscape streetscape in Toowoomba, Australia.

Special warning: Vandalism is a problem in dense urban areas because bottle tree has such a smooth trunk.