What's eating my iris 'clarence'?

Iris 'Clarence', a tall bearded iris, is susceptible to iris borer in North America, which tunnels into rhizomes and triggers bacterial rot. Aphids target buds and stems, slugs damage young leaf fans in spring, and thrips can bronze the flowers. In the UK, iris borer is absent but slugs and leaf spot are common issues.

Ragged feeding tunnels run from leaf tips into the rhizome; infected rhizomes develop a slimy, foul-smelling bacterial soft rot. Remove all dead foliage in autumn to destroy eggs. In spring, squish young larvae spotted in leaves before they descend. Apply pathogenic nematodes to moist soil in early spring.

Holes and irregular tears in leaf fans, particularly on young growth and in wet weather. Iron phosphate pellets scattered around rhizomes; hand-pick at night; avoid mulching directly over exposed rhizomes.

Clusters on emerging flower buds and stems cause distortion, honeydew, and secondary sooty mold. Water jet dislodgement; insecticidal soap spray; encourage hoverflies and parasitic wasps by planting umbellifers nearby.