Pest identification
What's eating my penstemon 'sour grapes'?
Slugs and snails
Signs: Ragged holes in young foliage and stems; shoot tips grazed to stubs; slime trails
Control: Ferric phosphate pellets; copper tape on pots; hand-removal at night; reduce nearby debris
Aphids
Signs: Soft insect colonies on shoot tips, stems, and buds; sticky honeydew; sooty mould
Control: Insecticidal soap or neem oil spray; encourage ladybirds and parasitic wasps; remove infested tips
Vine weevil
Signs: Root system eaten, plant wilts and lifts from soil easily; most damaging in autumn through spring
Control: Nematode drench (late summer); check roots when repotting; remove any white C-shaped grubs
Keep penstemon 'sour grapes' pest-free
Healthy plants resist pests best. Get the basics right:
Penstemon 'Sour Grapes' pests — FAQ
What is eating my penstemon 'sour grapes'?
Penstemon 'Sour Grapes' is most commonly damaged by slugs and snails eating new shoots, and aphids colonizing tender growth and flower buds. Vine weevil grubs attack roots, especially in containers. In wet years, leaf and bud nematodes can cause distorted foliage. Overall pest pressure is moderate for a garden perennial.
How do I get rid of slugs and snails on penstemon 'sour grapes'?
Ragged holes in young foliage and stems; shoot tips grazed to stubs; slime trails Ferric phosphate pellets; copper tape on pots; hand-removal at night; reduce nearby debris
How do I get rid of aphids on penstemon 'sour grapes'?
Soft insect colonies on shoot tips, stems, and buds; sticky honeydew; sooty mould Insecticidal soap or neem oil spray; encourage ladybirds and parasitic wasps; remove infested tips
How do I get rid of vine weevil on penstemon 'sour grapes'?
Root system eaten, plant wilts and lifts from soil easily; most damaging in autumn through spring Nematode drench (late summer); check roots when repotting; remove any white C-shaped grubs