What's eating my pelargonium 'rollisson's unique'?

Pelargonium 'Rollisson's Unique', a vigorous Unique pelargonium with aromatic foliage, is most commonly attacked by aphids on young shoots and geranium bronze butterfly caterpillars in the UK. Its scented leaves offer some deterrence to larger animals. Whitefly and vine weevil are secondary concerns in container growing.

Colonies cluster on shoot tips and flower stems, causing distorted growth, sticky honeydew deposits, and sooty mould on leaves. Dislodge with a water jet; treat with insecticidal soap or neem oil. Repeat applications weekly until clear.

Larvae tunnel into flower buds and stems causing wilting; frass visible at entry points; flower display is ruined. Cut out and destroy affected stems. Spray spinosad or pyrethrin. Check buds weekly throughout the flowering season.

Grubs eat roots in containers, causing sudden wilting; adults leave characteristic notches around leaf margins at night. Apply Steinernema kraussei nematodes to moist compost in late summer. Use physical barriers and inspect root balls at repotting.