Generally, natural tree shape is used. Due to different uses, the tree shape requirements are also different. Street tree seedlings require a straight trunk, a first branch height of 2.5 to 3.5m, a complete and plump crown, and evenly distributed branches. Courtyard shade trees require a large and dense crown, and the height of the first branch is lower than that of street trees. This can generally be done in winter or during transplantation.
Luan tree is a plant of the genus Luan tree in the Sapindaceae family.
Luanian leaves are clustered on the branches of the current year, spread out, with one, incomplete or occasionally two-turn pinnate leaves, up to 50 cm long; 7 to 18 leaflets (terminal leaflets) Sometimes connate with the uppermost pair of leaflets below the middle), sessile or with very short stalks, opposite or alternate, papery, ovate, broadly ovate to ovate-lanceolate, 3 to 10 cm long, 3 to 6 cm wide, with a short apex or short acuminate, a blunt to nearly truncate base, irregular blunt serrations on the edges, small pointed tips at the ends of the teeth, and sometimes the teeth near the base are sparse and notch-shaped, or have feather-like deep fissures. It reaches the midrib to form a bipinnate compound leaf. Only the midrib is scattered with wrinkled pubescence on the upper side. The lower side is bearded on the vein axils, and sometimes the back of the leaflets is hairy.
The cymes are 25 to 40 cm long, densely puberulent, with long and widely spread branches. The cymes on the last branches have 3 to 6 flowers, densely packed in the shape of a head. ; Bracts narrowly lanceolate, covered with small coarse hairs; flowers light yellow, slightly fragrant; pedicels 2.5 to 5 mm long; calyx lobes ovate, with glandular cilium on the edges, gnawing; petals 4, facing outward when blooming Reflected, linear oblong, 5 to 9 mm long, claws 1 to 2.5 mm long, villous, scales at the base of the petals initially yellow, then orange-red when blooming, with uneven deep lobes, covered with warts wrinkled hairs; 8 stamens, 7 to 9 mm long in male flowers, 4 to 5 mm long in female flowers, the lower part of the filaments are densely covered with white, spreading villous hairs; the flower disc is deflected, with rounded edges. Small lobes; ovary triangular, hairless except for cilium on the edges, reduced ovary densely covered with small coarse hairs.
The capsule is conical, with 3 edges, 4 to 6 cm long, the top is tapered, the fruit petals are oval, the outside is reticulated, the inside is smooth and slightly shiny; the seeds are nearly spherical, 6 to 8 in diameter. mm. The flowering period is from June to August, and the fruiting period is from September to October.
The Luan tree is a light-loving plant that is slightly tolerant of semi-shade; it is cold-tolerant; but it is not tolerant of flooding. Pay attention to the soil when planting. It is tolerant of drought and barrenness. It has strong adaptability to the environment and likes to grow in calcareous soil. Resistant to salt stains and short-term waterlogging. Luan tree has deep roots, strong tillering ability, medium growth rate, saplings grow slowly and then become faster, and have strong ability to resist smoke and dust. It is often cultivated in the Central Plains, especially in Yanling, Xuchang.
It has strong wind resistance, can withstand low temperatures of minus 25°C, and has strong resistance to dust, sulfur dioxide and ozone. They are mostly distributed in low mountains and plains below 1,500 meters above sea level, and can reach as high as 2,600 meters above sea level.
The Luan tree is produced in most provinces in northern and central my country. From Liaoning in the northeast to Yunnan in the southwest through the central part, it is more common in central and east China. The main breeding bases are Jiangsu, Zhejiang, Jiangxi, and Anhui. Henan is also one of the Luan tree production bases.