What's eating my penstemon 'raven'?

Penstemon 'Raven' is vulnerable to slugs and snails on soft new growth, aphids on shoot tips, and vine weevil grubs on roots — especially in containers over winter. Dark-flowered penstemons are no less attractive to pests than other cultivars. Powdery mildew in drought stress can also weaken plants and invite secondary pest attack.

Chewed young shoots and leaves; damage concentrated at or near ground level; silvery trails Ferric phosphate bait around plants; gritty mulch; hand-pick at night; reduce mulch depth in winter

Colonies on new growth and buds; honeydew, sticky leaves, ants attending colonies Water blast; neem oil or insecticidal soap; introduce or attract beneficial insects

Root loss causes wilting; container plants collapse in late winter without obvious above-ground cause Apply pathogenic nematodes in late summer to moist compost; remove visible grubs from pot roots