Perennials

This is a brief listing of some common problems that may affect specific species. Weather, climate, seasonal and stress related conditions will sometimes influence a plants likelihood of being affected by insects and disease, it is always good to know which insects may affect a particular plant so that timely measures can be taken to correct problems. This list covers perennials that are mainly planted and used in zones 3 - 6.

Acanthus species - Bear’s Breeches - Subject to slugs and snails.

Achillea species & cultivars - Yarrow - Occasionally bothered by powdery mildew, stem rot and rust.

Aconitum napellus - Monkshood - Subject to crown rot, verticillium wilt, powdery mildew, the four-lined plant bug, cyclamen mites and larkspur leafminer.. Other insect and disease's of Aconitum are the same as that of Delphinium.

Actaea species - Baneberry - No serious insects or disease problems.

Adenophora species - Ladybells - No serious insects or disease problems.

Aegopodium podagraria 'Variegatum' - Bishop’s Weed - Resistant to insects and disease, however occasionally bothered by a leaf blight in humid, wet weather.

Agastache foeniculum - Hyssops - Nothing of major consequence.

Ajuga species & cultivars - Carpet Bugle - Subject to crown rot, root rot, powdery mildew and nematodes.

Alchemilla mollis - Lady’s Mantle - Nothing of major consequence.

Allium species - Ornamental Onion - Subject to bulb rot.

Amsonia tabernaemontana - Willow Amsonia - No serious insects or disease problems.

Anaphalis triplinervis - Pearly Everlasting - Susceptible to larval damage.

Anchusa azurea & cultivars - Bugloss - Subject to crown rot in wet weather, six-spotted leafhopper and spider mites.

Anemone species & cultivars - Subject to the crescent-marked lily aphid, black blister beetle, leaf tiers, leaf rollers, leaf miners, root decay rust and thrips.

Anthemis tinctoria & cultivars - Golden Marguerite/ Chamomile - No serious insects or disease problems.

Aquilegia species & cultivars - Columbine - The major insects are the leaf miner and borer. Also bothered by powdery mildew, crown rot, black spot, rust, aphids, asiatic garden beetle, budworm, mealybugs, mites and others.

Arabis species & cultivars - Sandwort - Subject to the crescent-marked lily aphid. This aphid can spread mosaic and other virus diseases. Occasionally bothered by rust and mildew.

Arenaria species - Sandwort - Seldom bothered, but subject to and occasionally bothered by powdery mildew and leaf spots.

Arisaema triphyllum - Jack-in-the-Pulpit - No serious insects or disease problems.

Armeria maratima & cultivars - Sea thrift - Insect and disease problems are minor.

Artemisia species & cultivars - Wormwood - Rust disease can be a serious problem brought on by prolonged periods of wet foliage. Rarely bothered by insects. A. stelleriana is the most susceptible to larvae damage.

Arum italicum 'Pictum' - Painted Arum - Nothing of major consequence.

Aruncus dioicus - Goat’s Beard - Occasionally bothered by leaf spots and occasionally by fireblight disease since it is a member of the rosaceae family.

Asarum species - Ginger - Subject to and occasionally bothered by fungus in hot, humid weather and often slugs, otherwise relatively insect and disease resistant.

Asclepias tuberosa - Butterfly Weed - Insect and disease problems are few, nothing of major consequence.

Asphodeline lutea - No insect or disease problems.

Aster species & cultivars - Subject to rust, powdery mildew, verticillium wilt, aster wilt, six-spotted leafhopper, Japanese beetle and various aphids.

Asteromoea mongolica - Double Japanese Aster - No serious insects or disease problems.

Astilbe species & cultivars - Seldom bothered but subject to powdery mildew, black vine weevil, Japanese beetle and occasionally by slugs and snails.

Astrantia major & cultivars - Masterwort - No serious insects or disease problems.

Aubrieta deltoidea & cultivars - False Rock Cress - Not subject to any serious problems with any insects or disease.

Aurinia saxatilis & cultivars - Basket of Gold - No serious insects or disease problems.

Baptisia australis - False Indigo - No serious insects or disease problems.

Belamcanda chinensis & cultivars - Blackberry Lily - Iris borer can be a severe problem.

Bergenia cordifolia & cultivars - Nothing of serious consequence.

Bletilla striata & cultivars - Hardy Orchid - No serious insects or disease problems.

Boltonia asteroides & cultivars - Nothing of major consequence.

Brunnera macrophylla & cultivars - Bugloss - No serious insects or disease problems.

Buphthalmum salicifolium - Willowleaf Oxeye - No serious insects or disease problems.

Callirhoe involucrata - Poppy Mallow - No serious insects or disease problems.

Caltha palustris & cultivars - Marsh Marigold - No special insect or disease troubles.

Campanula species & cultivars - Bellflower - Subject to slugs and snails, rose beetle and root rot.

Catananche caerulea & cultivars - Cupid’s Dart - Nothing of any major consequence.

Centaurea species & cultivars - Bachelor’s Button - Generally free from insect and disease problems, although sometimes troubled by rust, aster yellows, root rot and root aphids.

Centranthus ruber & cultivars - Jupiter’s Beard - No serious insects or disease problems.

Cerastium tomentosum & cultivars - Snow-in-Summer - No serious insect or disease problems.

Ceratostigma plumbaginoides - Plumbago - No serious insect or disease problems.

Chelone species - Turtlehead - No unusual insect or disease problems to worry about.

Chrysogonum virginianum - Goldenstar - No serious insect or disease problems.

Cimicifuga species & cultivars - Bugbane - Nothing of any major consequence.

Convallaria majalis & cultivars - Lily of the Valley - Subject to root-knot nematodes, lily-of-the-valley weevil, anthracnose and highly susceptible to leaf spot.

Coreopsis species & cultivars - Tickseed - Only Coreopsis grandiflora and cultivars seem to be troubled by powdery mildew, leaf spots, rust, coreopsis and potato aphids, spotted cucumber beetle, six-spotted leafhopper and especially the four-lined plant bug which distorts the foliage with little brown spots.

Corydalis lutea - Insect and disease resistant.

Crambe cordifolia - No serious insects or disease problems.

Darmera peltata - No serious insects or disease problems.

Delphinium x elatum & cultivars - Subject to powdery mildew, crown rot, root rot, Botrytis blight, leaf spots, aphids, Asiatic garden beetle, black blister beetle, stalk borers, four-lined plant bug, leaf miner, cyclamen mites and two-spotted red spider mites.

Dendranthema x morifolium - Hardy Chrysanthemum - Subject to aphids, spider mites, leaf miner, borer, bacterial blight and leaf spots.

Dianthus species & cultivars - Cottage Pinks - Subject to crown rot, root rot. rust, and leaf spots, (all associated with damp, humid weather.) Also subject to aphids, red spider mites and black blister beetles. If you provide a bright, sunny area with good air circulation, you should rarely have any problems.

Dicentra species & cultivars - Bleeding Hearts - Subject to stem rot.

Dictamnus albus & cultivars - Gas Plant - No serious insects or disease problems.

Digitalis species & cultivars - Foxglove - Subject to powdery mildew, leaf spot, root rot, stem rot, aphids, Japanese beetle, mealybugs and red spider mites.

Dodecatheon meadia - Shooting Star - No insect or disease problems.

Doronicum orientale & cultivars - Leopardsbane - Insect and disease troubles affecting leopardsbane are minor but they are occasionally bothered by powdery mildew, crescent-marked lily aphid and sawfly.

Echinacea purpurea & cultivars - Purple Coneflower - Highly susceptible to Japanese beetle and sometimes bothered by leaf spots.

Echinops ritro & cultivars - Globe Thistle - Subject to aphids and the four-lined plant bug.

Epimediums species & cultivars - Barrenwort - Generally free of any insect or disease troubles.

Erigeron hybrids & cultivars - Fleabane - Subject to downy and powdery mildew, leaf spots, rust, aster yellows and aphids.

Erodium reichardii & cultivars - Heronsbill - Seldom bothered.

Eryngium species - Sea Holly - Occasionally bothered by leaf spots, beetles and leaf miner.

Erythronium species & cultivars - Dog-tooth Violet - Nothing of major consequence.

Eupatorium species & cultivars - Mist Flower/ Joe-Pye Weed - Subject to crown rot, rhizoctonia rot, botrytis blight, powdery mildew, aphids and leaf miner.

Euphorbia species & cultivars - Spurge - Cypress spurge can be attacked by a blight that affects the flowers then spreads to the foliage. Most other species are insect and disease resistant.

Filipendula species & cultivars - Queen of the Meadow - Occasionally bothered by powdery mildew during wet weather.

Gaillardia x grandiflora & cultivars - Blanket Flower - Subject to leaf spots, powdery mildew, aster yellows, asiatic garden and Japanese beetles, six-spotted leafhopper and the four-lined plant bug.

Galium odoratum - Sweet Woodruff - No serious insects or disease. Occasionally subject to fungal damage in humid conditions.

Gaura lindheimeri - White Gaura - No serious troubles.

Gentiana septemfida - Crested Gentian - Occasionally bothered by rust.

Geranium species & cultivars - Geranium/ Cranesbill - Occasionally bothered by leaf spots, mites, weevils and the four-lined plant bug.

Geum hybrids & cultivars - Geum - Occasionally bothered by spider mites.

Gillenia trifoliata - Bowman’s Root - No major problems.

Helenium autumnale & cultivars - Sneezeweed/ Yellow Star - Subject to powdery mildew, helenium snout beetle and root aphids.

Helianthemum nummularium & cultivars - Sunrose - No insect or disease problems.

Helianthus x multiflorus & cultivars - Perennial Sunflower - Subject to aphids, beetles and various bugs.

Heliopsis helianthoides var. scabra & cultivars - Sunflower Heliopsis - Subject to aphids.

Helleborus species - Lenten Rose - Occasionally bothered by leaf spot and crown rot.

Hemerocallis species, hybrids & cultivars - Daylily - No insect or disease problems, occasionally bothered by flower thrips, which injure only the flowers, preferring yellow and other light colored blossoms. Most injurious in June, causing blossoms to become streaked.

Heuchera species & cultivars - Alumroot - Occasionally bothered the strawberry root weevil, mealybugs, stem rot and powdery mildew.

Hibiscus species & cultivars - Mallow - Subject to aphids, scale, Japanese beetle, leaf spots. canker, rust and blight.

Hosta species & cultivars - Subject to crown rot, slugs and snails. The thicker, corrugated leaf varieties are somewhat more resistant to slugs and snails. Plant in well drained soils to prevent crown rot.

Houttuynia cordata 'Variegata' - Chameleon Plant - No serious insects or disease.

Hypericum calycinum - St. John’s Wort - No major problems.

Hyssopus officinalis & cultivars - Hyssops - No serious insects or disease problems.

Iberis sempervirens & cultivars - Candytuft - No serious insects or disease problems.

Inula ensifolia - Swordleaf Inula - Subject to mildew.

Iris species & cultivars - Bearded and Sweet Iris (Iris pallida) are highly susceptible to the iris borer, which produces ragged leaves and hollow rhizomes. The other Irises are not affected by this borer. Also subject to various aphids and beetles, verbena bud moth, zebra caterpillar, mites, several nematodes, scales, slugs and the Iris weevil. Japanese Iris is not troubled by these insects, but is highly susceptible to Iris thrips, which becomes evident by a blackened and stunted appearance of the inner leaves followed by the leaf tops turning brown and the eventually dying. The least susceptible Irises are the I. cristata, I. pseudocorus and I. siberica.

Kniphofia hybrids & cultivars - Red Hot Poker - No serious insect or disease problems, but occasionally bothered by leaf spots.

Lamiastrum galeobdolan 'Variegatum & cultivars - Yellow Archangel - Subject to slugs and snails.

Lamium maculatum & cultivars - Spotted Deadnettle - No serious insect or disease problems.

Lathyrus latifolius & cultivars - Perennial Sweet Pea - No serious insect or disease problems.

Lavandula angustifolia & cultivars - Lavender - No serious insect or disease problems.

Lavatera thuringiaca - Tree Mallow - Subject to Japanese beetle.

Leontopodium alpinum - Edelweis - No serious insect or disease problems.

Leucanthemum species & cultivars - Silver&Gold Chrysanthemum - Subject to leaf spots, stem rots, spotted cucumber beetle, chrysanthemum leaf miner, four-lined plant bug and tarnished plant bug.

Liatris species & cultivars - Blazing Star - No serious insect or disease problems.

Ligularia species & cultivars - Goldenray/ Ragwort - Subject to slugs and snails.

Lilium species & cultivars - Garden Lily - Subject to basal bulb rot in soils with poor drainage. Also subject to botrytis rot, leaf spots, mosaic, rust, crescent-marked lily aphids and the stalk borer.

Limonium latifolium & cultivars - Sea-Lavender - Subject to crown and root rot.

Linum perenne & cultivars - Perennial Flax - Subject to grasshoppers and cutworms.

Lirope species & cultivars - Lilyturf - No serious insect or disease problems.

Lobelia cardinalis & cultivars - Cardinal Flower - No serious insect or disease problems. Occasionally bothered by the red-banded leaf roller and the six-spotted leafhopper.

Lupinus 'Russell Hybrids & cultivars - Lupine - Subject to powdery mildew, rusts, lupine aphids, four-lined plant bug and the lupine weevil.

Lychnis species & cultivars - Rose Champion - Subject to leaf spots, root rot, rusts and smut, attacking Maltese Cross more so than Rose Campion.

Lysimachia species & cultivars - Loosestrife - Subject to crown rot and white fly.

Lythrum species & cultivars - Purple Loosetrife - Subject to Japanese beetle.

Macleaya cordata - Plume Poppy - Anthracnose can become a problem in warm, wet weather.

Malva alcea & cultivars - Hollyhock Mallow - Subject to Japanese beetle, spider mites and various foliar disease's.

Mertensia virginica - Virginia Bluebells - No serious problems but occasionally troubled by fungus.

Monarda didyma & cultivars - Beebalm - Subject to powdery mildew and rust.

Myosotis sylvatica & cultivars - Forget-me-not - Subject to aphids, potato flea beetle, thrips, red spiders and powdery mildew.

Nipponanthemum nipponicum - Nippon Chrysanthemum -No serious insects or disease problems.

Oenothera species & cultivars - Sundrops - Subject to root rot in wet soils.

Opuntia humifusa - No serious insects or disease problems.

Paeonia species & cultivars - Peony - Subject to botrytis and phytophthora blight, anthracnose, leaf blotch, stem rot, verticillium wilt, ants, rose beetle, four-lined and tarnished plant bugs, rose curculio, nematodes, stalk borer, San Jose and oyster shell scales. To control disease, remove and discard stems and foliage in the fall - do not put on compost pile.

Papaver species & cultivars - Poppy - Subject to bacterial blight, downy mildew, stem blight and aphids.

Patrinia triloba - No serious insects or disease problems.

Penstemon species & cultivars - Subject to crown rot and occasionally by leaf spot and rust, but not enough to warrant control measures. Subject to the crescent-marked lily aphid and the red-and-black stink bug.

Perovskia atriplicifolia & cultivars - Russian Sage - No serious insect or disease problems.

Persicaria virginiana 'Variegata' & cultivars - Tovara - No serious insect or disease problems.

Petasites japonicus - Butterbur - Occasionally bothered by slugs and snails.

Petrorhagia saxifraga & cultivars - Coat Flower - Nothing major.

Phlox species & cultivars - Phlox - Subject to powdery mildew, leaf spots, Asiatic garden beetle, black blister beetle, stalk borer, six-spotted leafhopper, four-lined and phlox plant bugs, two-spotted red spider mites, root-gall nematodes, stem nematodes and scales.

Physalis alkekengi & cultivars - Chinese Lantern - Subject to flea beetles, striped cucumber beetle and the four-lined plant bug.

Physostegia virginiana & cultivars - False Dragonhead - Occasionally bothered by rust.

Platycodon grandiflorus & cultivars - Balloon Flower - Insect and disease resistant.

Podophyllum peltatum - Mayapple - No insect or disease's of any consequence.

Polemonium species & cultivars - Jacob’s ladder - Not subject to any insect or disease to warrant control measures.

Polygonatum species - Solomon’s Seal - No serious insects or disease problems.

Polygonum species & cultivars - Fleeceflower - No serious insects or disease problems.

Potentilla species & cultivars - Cinquefoil - No serious insects or disease problems.

Primula species & cultivars - Primrose - Subject to various aphids, fuller rose and potato flea beetles, two-spotted red spider mites, nematodes, slugs, black vine weevil, crown rot and chlorosis, a physiological disease which is thought to be due to intense acidity in the soil.

Prunella grandiflora & cultivars - Bigflower Selfheal - Nothing of major consequence.

Pulmonaria species & cultivars - Lungwort - No serious insect or disease, however it is occasionally bothered by powdery mildew, especially Bethlehem Sage.

Pulsatilla vulgaris & cultivars - Pasque Flower - No serious insects or disease problems.

Ranunculus repens 'Flore Pleno' - Creeping Buttercup - Nothing of major consequence.

Ratibida columnifera - Prairie Coneflower - No serious insects or disease problems.

Rodgersia species & cultivars - Rogersia/ Roger’s Flower - No serious insects or disease problems.

Rudbeckia species & cultivars - Black-eyed Susan/ Gloriosa Daisy - Black-eyed Susan in particular is subject to downy mildew, powdery mildew, rust, brown ambrosia and crescent-marked lily aphids, garden fleahopper bug, six-spotted leafhopper and sawfly.

Sagina subulata & cultivars - Irish / Scotch Moss - Nothing of major consequence.

Salvia species & cultivars - Common Sage - Subject to foxglove aphid, asiatic garden beetle, stalk borer, tarnished plant bug and various scales.

Sanguisorba species - Burnet - Nothing of major consequence.

Santolina species & cultivars - Lavender Cotton - No serious insect or disease problems.

Saponaria species & cultivars - Soapwort - No serious insect or disease problems.

Saxifraga species & cultivars - Saxifrage - Subject to aphids, beetles, slugs and rust.

Scabiosa caucasica & cultivars - Pincushion Flower - Subject to fuller rose beetle, chrysanthemum lace and garden fleahopper bugs, six-spotted leafhopper, slugs and snails, root rot and mildew.

Sedum species & cultivars - Stonecrop - No serious insect or disease problems, although the tall varieties are occasionally bothered by aphids.

Sempervivum species & cultivars - Houseleeks/ Hens & Chicks - Subject to crown rot and rust.

Sidalcea malviflora & cultivars - Checkermallow - Subject to Japanese beetle and rust.

Silene species & cultivars - Champion - Subject to sooty mold.

Sisyrinchium species & cultivars - Blue-eyed Grass - No serious insect or disease problems.

Solidago hybrids & cultivars - Goldenrod - Subject to rust.

Spigelia marilandica - Indian Pink - Nothing of major consequence.

Stachys species & cultivars - Lamb’s Ear - No serious insects or disease problems, however it can develop a mold-like fungus or mildew on its foliage when weather conditions become hot, humid and wet. This plant also dislikes it’s foliage being wet.

Stokesia laevis & cultivars - No serious insect or disease problems.

Stylophorum diphyllum - Wood poppy - No serious insect or disease problems.

Symphytum species - Comfrey - No serious insect or disease problems.

Tanacetum species & cultivars - Painted Daisy/ Feverfew - No serious insects or disease problems.

Tellima grandiflora & cultivars - False Alumroot/ Fringecup - No serious insects or disease problems.

Teucrium species & cultivars - Wild Germander - Generally not troubled, but subject to downy and powdery mildew, leaf spots, rusts and mites.

Thalictrum species & cultivars - Meadow Rue - Subject to powdery mildew, rusts and smut diseases, but generally not troubled.

Thermopsis species - Themopsis/ Carolina Lupine - No serious insects or disease problems.

Thymus species & cultivars - Thyme - Subject to fungal disease and root rot. Wooly thyme is highly susceptible to fungus disease in wet, damp weather. Plant only in full sun with good air circulation and in a soil with good drainage.

Tiarella species & cultivars -Foam Flower - No major insect or disease problems.

Tradescantia x andersoniana & cultivars - Spiderwort - Subject to botrytis blight, leaf tier, leaf cutter and the orange tortix caterpillar, although none are of major consequence.

Tricyrtis hirta & cultivars - Toad Lily - No serious insects or disease problems.

Trillium grandiflorum & cultivars - Wake-Robin - Subject to rust, although not serious.

Trollius species & cultivars - Globeflower - Sometimes troubled by powdery mildew.

Uvularia grandiflora - Bellwort - No serious insects or disease problems.

Vancouveria hexandra - American Barrenwort - No serious insects or disease problems.

Verbascum chaixii - Mullein - Subject to the red-and-black stink bug and to spider mites in hot areas.

Vernonia noveboracensis - Ironweed - No serious insects or disease problems.

Veronica species & cultivars - Speedwell - Subject to downy mildew and leaf spot in humid areas. Generally not troubled much by insects and disease.

Veronicastrum virginicum & cultivars - Culver’s Root - No major insect or disease problems.

Viola odorata & cultivars - Violet - Subject to anthracnose, downy mildew, leaf spots, crown rot, root rot, cutworms and slugs. Occasionally bothered by aphids, caterpillars and red spiders.

Waldsteinia fragarioides - Barren Strawberry - No serious insects or disease problems.

Yucca species & cultivars - Yucca/ Adam’s Needle - Occasionally bothered by leaf spots and leaf blight.

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