What's eating my lawson cypress?

Lawson Cypress is devastated by the cypress aphid (Cinara cupressi) in the UK, which causes sudden large-scale browning and death of established hedges — the most notorious pest of this species. Phytophthora root rot also kills plants. Juniper scale and spider mites cause milder foliage damage. Rabbits bark-strip young stems.

Large grey-brown aphids feed on stems under foliage, often unseen until damage appears as brown patches in the hedge interior in late summer; patches spread rapidly and affected foliage dies — often irreversibly; a single season of heavy feeding can kill large sections of a mature hedge Inspect hedges closely in June–August parting foliage to look for aphid colonies; spray with insecticidal soap, pyrethrin, or systemic thiacloprid/acetamiprid at first detection; avoid growing solid blocks — leave gaps or mix species to slow spread

Minute white-grey armoured scales encrust foliage and stems; sustained infestations cause yellowing, sparse growth, and progressive dieback; sooty mold may develop Dormant horticultural oil before bud break; systemic imidacloprid soil drench for persistent infestations; prune and dispose of heavily scaled branches; encourage natural predators

Foliage takes on a dull, grey-bronze tint with fine webbing inside the canopy; needle drop from older wood reduces interior density; worse in hot, dry conditions Horticultural oil dormant spray; miticide or insecticidal soap during active periods; overhead irrigation helps suppress populations; avoid water stress

Rabbits ring-bark the lower stems of young plants and hedge whips, girdling and killing them; they may also nip leading shoots, slowing establishment Wrap lower stems of newly planted whips in spiral tree guards or chicken-wire cylinders for the first 2–3 years; rabbit-proof fencing where populations are high