| everytime you cut the top of the wisteria off as it grows too tall, that top of the plant then splits into 2, giving you 2 tops.
once you top the plant it focuses its growth on new growth in the side shoots, making a bushier plant rather than a taller plant
when i "top" my plants (trim them from growing too tall), to replant just pull off the last few leaves on the bottom and pluck it in the gravel! it'll grow roots and everything fine on its own, meanwhile the mother plant you took the clipping from will produce the side shoots, and instead of one top it will split into 2 |