Wisteria is a show-stopping vine when it is in bloom, and can be trained into a classic tree form for use as a bonsai. Whether you grow the Chinese variety, Wisteria sinensis or the Japanese, Wisteria floribunda, both require careful attention to detail to produce a beautiful tree. This article will address the care needs of both species and provide tips for training and shaping the trunk of a wisteria bonsai.
Depending on the desired style, pruning of a wisteria is done from late winter to autumn. Pruning for shape, thinning and backbudding (inducing the growth of new buds) will help to achieve the desired aesthetics.
As with all trees, wisteria grown as a bonsai requires proper soil maintenance. Ideally, a well-draining mix is used to allow the delicate roots to thrive. A blend of loam and sand, with some coarse lava rock and pumice, works well. Some wisteria also display small black nodules in their roots; these are nitrogen-fixing nodules that are helpful to the plant.
Watering should be regular, and should be performed to the point of saturation; however, the soil should never become waterlogged. It is best to use a drip system or a watering can with a fine spray nozzle.
Like most lilacs, wisteria should be fed regularly throughout the year, with heavy feeding before and during flowering. However, in the spring and summer, fertilization should be reduced to encourage vegetative growth; this can be done by placing the wisteria in a tray of water where the tree can soak up the nutrients as needed.