Acacia cultriformis (knife-leaf wattle, "Sankakubaakashia")

Japanese name: サンカクバアカシア
Scientific name: Acacia cultriformis

[Overview]
An evergreen shrub 2–3 m tall, not exceeding 4 m even when large.
The twigs are ridged, glaucous and hairless.
The leaves are alternate in a dense spiral, and are phyllodes (flattened leaf stalks that function as leaves), asymmetrical triangles 1–3.5 cm long and about 1 cm wide, gray-green.
Only one vein is conspicuous on each phyllode, and a gland is attached at the apex on the branch side.
At the branch tips, globose flower heads gather further into racemes, bearing many golden-yellow flowers.
The fruit is a flat pod 3–10 cm long.

[Cultivation]
Propagate from seed.
To promote germination, soak freshly collected seeds in 80°C hot water for 30 minutes, leave them in the water for half a day to 2 days, and then sow.
The optimum germination temperature is 20–25°C, and germination begins about 1–3 weeks after sowing.
It prefers a sunny, well-drained site.
In warm regions south of the Kanto region, it can overwinter in open ground.
It will not flower unless it receives enough sun.
Strong wind can break branches and trunks, so avoid windy sites.
It tolerates light frost.
Established plants need no watering unless the soil becomes extremely dry.
In summer, water in the morning or evening when the temperature is low.
Pruning hard after flowering can prolong the life of the tree.
Mature trees are difficult to transplant, but if it is unavoidable, root pruning should be done the previous year.
Pests and diseases include scale insects and aphids.

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