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Pest identification

What's eating my large-flowered beardtongue?

Aphids

Signs: Colonies on stem tips and flower buds; honeydew residue and distorted new leaves.

Control: Knock off with water; apply insecticidal soap or neem oil; encourage ladybirds and lacewings.

Penstemon borer (Penstemonia haydenii / Sphinx caterpillars)

Signs: Caterpillars tunnel into stems, causing wilting of individual stems or the whole shoot.

Control: Cut and destroy wilted stems; apply Bacillus thuringiensis (Bt) spray when young caterpillars are active.

Deer & rabbits

Signs: Flower stalks and foliage browsed, especially in spring when growth is lush.

Control: Use wire guards or deer-repellent sprays around the plant; site near paths or structures to deter wildlife.

Keep large-flowered beardtongue pest-free

Healthy plants resist pests best. Get the basics right:

Large-Flowered Beardtongue pests — FAQ

What is eating my large-flowered beardtongue?

Large-Flowered Beardtongue (Penstemon grandiflorus) is a tough native prairie plant. Its chief pest threats are aphids on new growth, penstemon borer caterpillars that tunnel stems, and deer or rabbits browsing the showy flower stalks. Well-drained soil and good air circulation prevent the root rots that invite secondary pest stress.

How do I get rid of aphids on large-flowered beardtongue?

Colonies on stem tips and flower buds; honeydew residue and distorted new leaves. Knock off with water; apply insecticidal soap or neem oil; encourage ladybirds and lacewings.

How do I get rid of penstemon borer (penstemonia haydenii / sphinx caterpillars) on large-flowered beardtongue?

Caterpillars tunnel into stems, causing wilting of individual stems or the whole shoot. Cut and destroy wilted stems; apply Bacillus thuringiensis (Bt) spray when young caterpillars are active.

How do I get rid of deer & rabbits on large-flowered beardtongue?

Flower stalks and foliage browsed, especially in spring when growth is lush. Use wire guards or deer-repellent sprays around the plant; site near paths or structures to deter wildlife.