Chinese wisteria vs Trumpet vine

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.

It sends up plenty of suckers from its roots, even several metres from the parent plant, in lawns, beds and paving joints, and it also seeds itself from winged seeds; a neglected plant forms an impenetrable thicket. Plant it where you can mow around it or where paving contains it. The aerial roots grip render and mortar joints, so pulling them off damages render and paint, and the heavy woody stems can lift roof tiles and grow under eaves and into gutters, so keep it well away from the roof on a house wall. Because it flowers on the current year's shoots you can cut it back hard in early spring. Young shoots may be killed back in a hard winter, but the plant resprouts. Aphids can settle on it.