What's eating my wisteria floribunda 'multijuga'?

Wisteria floribunda 'Multijuga' (syn. 'Macrobotrys'), grown for its exceptionally long flower racemes, is prone to the same pests as the species: scale insects on old wood threaten flowering wood, aphids attack new growth, and vine weevils can damage roots. Protecting the previous-year stems from scale is the single most important pest-management task for reliable blooms.

Clusters of dome-shaped brown scales on bark cause honeydew, sooty mould, and gradual dieback of spur-wood needed for next year's flower racemes. Brush off manually in winter; apply dormant horticultural oil spray; target crawler stage in late spring with insecticidal soap for severe colonies.

Dense colonies on new shoot tips in spring; sticky distorted growth; excess nitrogen feeding makes plants more attractive to aphids. Spray with insecticidal soap or neem oil; pinch out heavily infested tips; limit high-nitrogen feeds — use a low-nitrogen fertiliser in spring.

Leaf-margin notching by adults; more seriously, larvae eat roots and can cause sudden wilt, especially in container-grown specimens. Apply pathogenic nematodes to moist soil in late summer; use proprietary vine weevil drench for pot-grown plants; ensure good drainage to deter egg-laying.