Wisteria

Plant against a south or west-facing wall for the best flowering. Wisteria needs full sun and warmth to initiate flower buds. Use strong horizontal wires fixed 45 cm apart to support the heavy stems. Always buy grafted plants (not seed-raised), as seed-grown wisteria can take 15-20 years to flower. Plant in fertile, well-drained soil and water regularly in the first two years. Avoid high-nitrogen feeds, which promote leaf growth at the expense of flowers. A sulphate of potash feed in early spring encourages flowering. Wisteria sinensis twines anticlockwise; Wisteria floribunda twines clockwise.

Prune twice a year for the best flowering. In late July or August, cut back the long, whippy side shoots of the current season to five or six leaves from the main stem. In January or February, shorten these same shoots further to two or three buds. This spur-pruning system concentrates the plant's energy into producing flower buds rather than vegetative growth.