What's eating my rocky mountain penstemon?

Rocky Mountain penstemon is a resilient western native largely avoided by deer and most insects. Grasshoppers and flea beetles are the biggest defoliating threats in its native range, while spider mites may appear in hot dry summers. Slugs can damage seedlings in wetter climates but established plants tolerate most pest pressure well.

Leaves and stems chewed rapidly; repeated feeding over a dry summer can strip plants bare and weaken the crown. Encourage birds and parasitic wasps; apply kaolin clay or spinosad during population peaks.

Shot-holes through leaves from adult feeding; larvae may gnaw roots and stem bases, causing wilting in young plants. Use row cover on transplants; apply neem oil or pyrethrin to foliage; cultivate soil around the crown to expose larvae.

Yellow stippling on leaf surfaces and fine webbing on undersides; most problematic on plants stressed by drought or heat. Water plants consistently during dry spells; remove infested foliage; spray with neem oil or insecticidal soap.