What's eating my catawba rhododendron?

Catawba rhododendron faces lace bugs, black vine weevils, and scale insects outdoors. Deer browse foliage and buds, especially in winter. Lace bugs are the most persistent threat, causing widespread bleaching on plants in sunny spots. Regular monitoring, proper siting in partial shade, and targeted treatments keep populations manageable.

Upper leaf surface turns yellow and stippled; underside shows dark, varnish-like tar spots from excrement. Severe infestations cause premature leaf drop. Spray the undersides of leaves with insecticidal soap, neem oil, or a pyrethroid. Imidacloprid soil drench provides systemic season-long control. Worst on sun-exposed plants — move to partial shade where possible.

Adults notch leaf margins with characteristic scalloped bites in spring and late summer. Larvae feed on roots, causing wilting and plant decline, especially in container-grown plants. Hand-pick adults at night. Apply insecticide spray (pyrethroid) to foliage in spring when first notching appears. Use beneficial nematodes (Heterorhabditis spp.) applied to moist soil in late summer to target larvae.

Sap-sucking causes leaf yellowing, branch dieback, and sticky honeydew that promotes black sooty mould. Small brown or white waxy bumps visible on stems and leaf undersides. Apply horticultural oil in late winter before budbreak to smother overwintering scales. Follow with a systemic insecticide (imidacloprid) in spring for heavy infestations. Encourage natural predators such as parasitic wasps.

Browse leaves, flower buds, and branch tips, especially in late winter when other food is scarce. Repeated browsing stunts growth and ruins flowering. Use physical exclusion (wire caging or deer fencing) around young plants. Apply deer repellent sprays (egg-solid or capsaicin based) and reapply after rain. Choose a sheltered planting site.