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Bolusanthus speciosus

Accession Count: 3
Common Name: tree wisteria
Family Name: Fabaceae
Botanical Name: Bolusanthus speciosus
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics:
Bolusanthus speciosus is a briefly deciduous, slow growing tree and the only member of the genus Bolusanthus. Its fragrant, blue-violet flowers, clustered in pendulous racemes like those of Wistera, can completely cover the tree. It blooms in spring on bare branches after leaf drop and before leafout. The fruit are grayish seedpods containing 3-8 smooth yellow to brown seeds. The leaves are compound with up to 7 leaflet pairs and a terminal leaflet, alternate, and spirally arranged, suspended from drooping branches. The leaflets are lance shaped and shiny green.  It is most often a multi stemmed plant but can be trained to a single trunk with bark that becomes rough, gray-brown, and deeply fissured with age. The root system is non-invasive. 
Compound: Bol spe
Geographic Origin: Grasslands of southern Africa
Ecozone Origin: Afrotropic
Biome Origin:
Natural History:
This tree is native to wooded grasslands of southern Africa, from Angola and Zambia in the north to KwaZulu-Natal in the south. Bees and butterflies are attracted to the flowers. Mammals browse the leaves and eat the pods.
Cultivation Notes:

This tree flourishes in a hot dry climate that has only moderate frost. Locate it in USDA Hardiness zones 10-11, in full sun, where it can receive shelter from strong winds. Protect it from freezing during its first three years. Water twice a week during the warm season during its first year, then weekly, then every one or two weeks. It begins to bloom after 2-4 years in the ground while still quite small.

To propagate, soak seeds overnight in hot water before planting. Germination should start within the first week but may take up to a month. Once the second leaf has emerged the plant can be transplanted into a soil mixture that contains sand, loam, and compost. 
Ethnobotany:
Tree wisteria is ideal for residential gardens because of its non-invasive roots, its slow growth, and its spectacular spring bloom.
Height: 20 - 50 feet
Width: 20 - 50 feet
Growth Rate: Slow Growing
Grow Season:
Flower Season: Spring
Color: Blue
Function: Shade
Spread:
Allergen: Non-allergenic
Invasive: Benign
Toxicity: Benign
Hardy: Tender
Water Use: Moderate Water Use
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Bolusanthus speciosus