Caragana arborescens 'Pendula'

Synonyms: weeping yellow acacia, weeping tree caragana

Caragana arborescens var. pendula Carrière – a decorative form of the deciduous shrubs of the species Caragana arborescens (family Caragana). It was first described by the French botanist Elie-Abel Carrière in 1856 in «J. Gén. Hort.» 11:165.

It is a tree grafted on a stem, 2-3 m high and wide. The crown is weeping. It grows rapidly during the first 3 years, reaching 3.2 m in height in 10 years, with a crown diameter of 2 m. Stem thickness 10-15 cm, with smooth, shiny, greenish-brown bark. Young shoots are covered with greenish or yellow-green bark, angled, appressed-hairy. Branches are pendulous, picturesquely hanging toward the ground. Buds are ovate-conical, 5-10 mm long, dry-membranous, scales light-reddish or grayish-brown, set deeply in the axils of leaf cushions. Leaf scar large, with 2 brittle often deciduous spines on the sides. Pith rounded or slightly angular. Wood greenish-brown, heartwood brown. Stipules awl-shaped, sharp, deciduous or transformed into a spine up to 1 cm long.

Photo by V. Sviridenko

Leaves alternate, pinnate, composed of 5-8 pairs of opposite leaflets. Leaflets entire-margined, obovate or oblong-elliptic, 8-35 mm long and 5-13 mm wide, rounded at both ends, with a short point at the apex, initially hairy, later almost glabrous. Petioles deciduous, thin, up to 9 mm long, pubescent, less often glabrous.

Photo by V. Sviridenko

Flowers large, bisexual, papilionaceous, solitary or grouped in clusters of 2-5 (4). Pedicels 2-6 cm long, pubescent, gathered in clusters of 2-5, articulated in the upper part. Calyx bell-shaped, up to 6 mm long, pubescent, with short and broad teeth, 6 times shorter than the tube. Corolla yellow, 17-19 mm long; the standard blade widely obovate, suddenly narrowed into a short claw; wing blades narrowed in the upper part, claws 1.5 times shorter than the blade, the auricle 3 times shorter than the claw; keel blunt, with its claw slightly shorter than the blade. Stamens 10, 9 of which are fused into a tube, 1 free. Ovary pubescent or glabrous. Nectariferous tissue at the base of the corolla. Pollen pale orange. Flowers in May-June.

Photo by V. Ivanov

Fruits are pods of a linear-cylindrical shape, 3-6 cm long and 3.5-5 mm wide, blackening, valves twisting, with 3-5 (8) seeds. Seeds brown, glossy. Ripen in July-August. Number of seeds per 1 kg – 40,000 pieces. Begins fruiting from 2 years of age.

Photo by N. Degterev

Hardiness zone: 3f (-45°C)

Location: sun-loving, but can also grow in partial shade. Undemanding to soil and moisture, but prefers fresh, slightly acidic or neutral, loamy or sandy loam soils. Tolerates any salinity and compaction of soil, as well as prolonged drought. Minimum groundwater level 1.5 m, does not tolerate waterlogging.

Planting: for creating a single-row hedge the recommended distance between plants is 50 x 50 cm, for a double-row 70 x 50 cm. Planting depth 50 cm, possible to deepen the root collar by 1-2 cm. Planting is best carried out in spring or autumn. On heavy soil drainage of crushed stone or gravel 20-25 cm thick is necessary. When planting you can add 150-200 g of mineral fertilizer. Watering is mandatory – 10-15 L per plant.

Care: in young plantings it is recommended to perform shallow loosening and mulching with peat in a layer up to 5 cm.

Pruning: tolerates cutting well. Cleaning of the stem is obligatory.

Propagation: propagated by seeds and vegetatively. Seeds are best sown immediately after ripening in a cold frame. They germinate in 2 weeks. If seeds are stored before planting they should be soaked for 24 hours in warm water and sown in a cold frame. In this case, seeds germinate within 2-3 weeks at 20°C. Seed viability 90-100%. Semi-ripe cuttings are cut 7-10 cm long and planted in July-August. Produces abundant root suckers. Ornamental forms are propagated by grafting.

Diseases: rust (use 3-5% solution of Bordeaux mixture). Nitrogen-fixing bacteria live in symbiosis on the roots.

Pests: acacia aphid, acacia leafhopper, acacia false scale (use 0.4% solution of Rotoran). Buprestids, clearwing moths, longhorn beetles (use phthalophos at 1% concentration).

Uses: used in solitary plantings. Looks effective on a lawn, in mixed groups with perennials.