What's eating my penstemon heterophyllus 'electric blue'?

Penstemon heterophyllus 'Electric Blue', a Californian native beardtongue, is inherently tough and has few pest enemies. Aphids occasionally infest stems and flower spikes. Flea beetles can chew small holes in leaves, and weevil larvae may attack roots if drainage is poor. It is notably resistant to slugs.

Clusters on flower stems and new growth; distorted shoots, sticky honeydew, and possible sooty mould. Spray with insecticidal soap or knock off with a strong jet of water. Avoid over-fertilising with nitrogen, which promotes the soft growth aphids prefer.

Numerous small, round holes scattered across leaves; heavy infestations can weaken young or newly planted specimens. Apply a fine-mesh fleece over young plants. Treat with pyrethrin spray if damage is severe. Healthy, established plants tolerate light damage.

Larvae eat roots and crown tissue in pot-grown or poorly drained specimens, causing wilting with no obvious above-ground cause. Apply nematodes (Steinernema kraussei) to moist, warm soil. Ensure excellent drainage — waterlogged roots are more vulnerable to larval attack.