Chinese wisteria vs Japanese wisteria

Late spring frosts in Central Europe can damage flower buds and open flowers. Seed-grown plants (cheap plants sold without a cultivar name usually are) may not flower for 10 to 15 years, so buy a grafted or cutting-grown plant sold under a cultivar name; shade, excessive nitrogen and incorrect pruning can also reduce flowering. Waterlogging can cause root rot, and strongly alkaline soil can produce iron chlorosis. Prolonged dry spells require supplementary watering. It needs a very strong, permanent support (heavy timber, steel pipe, tensioned steel wire), because its stems thicken to the width of an arm and can crush weak supports, damage gutters and strangle small trees; check regularly for suckers and shoots rooting into the soil. Garden escapes have been documented in Central Europe, but an official invasive classification could not be established clearly from the sources examined.

Its strong twining stems crush whatever they wrap around: gutters, downpipes, railings and lightning conductors, and they also grow under roof tiles and into gaps. Keep it at least two metres away from eaves and downpipes and prune it in summer and again in late winter. The early flower buds can be killed by late spring frost, leaving few flowers that year. Flowering can also fail in shade, after pruning at the wrong time or on seed-raised plants. Old grafted plants occasionally die at the graft union, and scale insects can attack it.