Uniquely identifiable characteristics
Distinguishing Feature :
A climbing garden plant up to 9m high with lavender/mauve flowers hanging down in trusses. It is also available in many differing varieties with differing colour schemes. Naturalised in only one hectad in the UK, much more likely to be found growing (twining clockwise) up the walls of a large house. Being a climber it requires a wall of trellis up which to climb. Sometimes planted under an existing tree such that it can clamber up and flowers droop down from the tree as if they were its own. It will only start flowering several years after planting. The flowers appear before the leaves in early summer, the foliage only appearing when the flowers are nearly finished.
It is said that all parts of this plant contain the toxic glycosidic steroidal compound (or saponin) called
wisterin, especially the seeds, consumption of just two or three of which can be fatal to children. It is a laxative. Symptoms are severe discomfort, nausea and vomiting, but it can be used as a diuretic in the treatment of some heart problems.
Wisterin should not be confused with another totally un-related compound with the same name of 'Wisterin' and which is produced by a marine sponge. The Author has been un-able to find with any degree of confidence the true chemical structural formula of the Wisterin within wisteria.
It also contains a one or several compounds from a family of long-chain amino acid polypeptides/proteins called
Cystatins, which are too complex to show here, but which are Cystein protease inhibitors, and therefore poisonous. They interact with other chemical workings of the body, putting various spanners in the works. One Cystatin is in the venom produced by the Puff Adder.
In the USA it is classed as a fast-growing unwanted weed having a large ecological threat. It shades out competing plants and also twines around eventually encircling them. Trees thus encircled die as they try in vain to grow in girth. On the ground new sprouts shoot up from seeds or rootstock, by which means it spreads rapidly. In the UK, Wisteria seems well behaved but a changing climate may alter this ~
The above two benzopyrans are β-chromenes (not to be confused with chromanones nor with chromones which are based on 1,4-benzopyrone), both found in Wisteria sinensis. They are both aromatic and contribute to the floral odour of Wisteria, as well as
Phenylacetoin (3-hydroxy-4-phenyl-2-butanone) shown below which is not a β-chromene.