What Is Eating My Petunias? Finding the Hidden Feeder

When something is eating your petunias, the number one suspect is the tobacco budworm — a small caterpillar that chews into buds so the flowers open full of holes or never open at all. Slugs, earwigs, rabbits, and deer are the other common culprits, and a five-minute flashlight check at dusk will usually reveal which one you have.

A striped tobacco budworm caterpillar on a plant stem
The tobacco budworm — the classic petunia pest that bores into buds so flowers never open. Photo: Whitney Cranshaw, Colorado State University, CC BY 3.0 us

Most likely causes

  • Tobacco budworms — holes chewed in buds, flowers that fail to open, worst mid to late summer
  • Slugs and snails — ragged holes on lower leaves with shiny slime trails
  • Earwigs — nighttime petal damage, insects hiding deep inside blooms by day
  • Rabbits — whole plants clipped down to stubs, cleanly cut
  • Deer — plants grazed flat or pulled from containers, ragged bites

Not quite what you're seeing? Answer four quick questions and the clue finder will point you to a closer match.

Compare the possible causes

Possible cause Key signs When it happens How likely
Tobacco budworms Round holes bored into flower buds, blooms that open pre-shredded or never open, and small dark droppings on the leaves below Mid to late summer, getting steadily worse from July into September Very common
Slugs and snails Irregular ragged holes concentrated on lower leaves and blooms, with dried silvery slime trails on foliage, pots, or nearby pavement Damp spells in spring and summer, on nights after rain or heavy watering Common
Earwigs Petals with small ragged chew marks after warm nights, and slim brown insects with rear pincers hiding deep inside blooms or under pot rims by day Early to mid-summer nights, especially in mulched beds and crowded containers Common
Rabbits Entire stems and plants clipped off cleanly an inch or two above the soil, often overnight, with pea-sized round droppings nearby Any time in the growing season; new spring plantings are hit hardest Common
Deer Plants grazed down to ragged stubs or yanked partly out of the ground, sometimes with heart-shaped hoofprints in the bed Overnight or early morning, year-round wherever deer pressure is high Less common

Visual clues to check

  • Go out at dusk with a flashlight and check the blooms — budworms and earwigs feed openly in the evening and are easy to spot then
  • Inspect the buds: a small round hole bored in the side of an unopened bud is the tobacco budworm's calling card
  • Look for pepper-like black droppings on leaves below the flowers — fresh budworm frass means caterpillars are active right above it
  • Scan for slime: silvery dried trails on leaves, pot sides, or pavement point to slugs or snails, not insects
  • Shake a damaged bloom over your palm — earwigs hiding inside will drop out
  • Judge the scale of loss: holes and failed blooms mean insects; entire plants clipped to stubs mean rabbits or deer
  • Match caterpillars to blooms: budworms take on their food's color, so check purple flowers for purplish caterpillars, not just green ones

The causes in detail

Tobacco budworms

This is THE classic petunia pest. Budworm caterpillars grow to about three-quarters of an inch and take on the color of what they eat — greenish, tan, even pinkish on red blooms — which makes them remarkably hard to spot in daylight. They bore into buds and eat the flower from the inside, so the plant looks healthy but simply stops blooming. They emerge to feed openly at dusk, which is exactly when to hunt them. Petunias, geraniums, and nicotiana are their favorite targets.

Slugs and snails

Slugs work from the ground up, so damage that starts low and heavy is their signature — a budworm attacks the top of the plant, a slug attacks the bottom. They shelter by day under pots, mulch, and boards, then rasp holes in leaves and petals overnight. The glistening trail is definitive: no insect leaves one. Container petunias on a shady, frequently watered patio are prime territory.

Earwigs

Earwigs are night feeders that adore the tight crevices a trumpet-shaped petunia bloom provides. Shake a damaged flower over your hand and one may tumble out. Their damage is shallower and more scattered than budworm boring — nibbled petal edges rather than holed buds. Despite the menacing pincers, they don't sting and are harmless to people; in modest numbers they even eat aphids.

Rabbits

When petunias vanish wholesale rather than developing holes, think mammal, not insect. Rabbits snip stems at a neat 45-degree angle with their paired incisors and can level a fresh flat of annuals in one night. Ground-level beds and low borders suffer most — rabbits rarely bother hanging baskets or tall containers, which is a useful diagnostic in itself. See all rabbits signs →

Deer

Petunias aren't a deer favorite, but hungry deer eat them readily, especially in late summer when wild forage dries up. Deer tear rather than snip, leaving mashed, ragged stem ends, and they can reach window boxes and raised planters that rabbits can't. Tracks and large oval droppings settle the question quickly. See all deer signs →

When to worry

  • The plant has stopped blooming entirely — budworms can eat every bud faster than the plant makes new ones
  • Damage is spreading to your geraniums, calibrachoa, or snapdragons, which budworms also favor
  • Whole plants keep disappearing within days of replanting, meaning a rabbit or deer has your bed on its nightly route
  • Slug numbers keep climbing in a bed where pets play — heavy hand-baiting temptation is a hazard sign to slow down and choose pet-safe methods
  • Container plants collapse suddenly — check whether feeding is happening at the roots or crown rather than the flowers

What to do now

  1. Hand-pick budworms at dusk for several evenings in a row and drop them in soapy water — with a small planting, this is genuinely the most effective control
  2. Pinch off and discard any bud with a bore hole; the caterpillar is often still inside it
  3. Trap earwigs by laying a loosely rolled, dampened newspaper near the pots overnight, then shake the sheltering earwigs into soapy water each morning
  4. Reduce slug habitat: water in the morning instead of evening, elevate pots, and clear boards, dense mulch, and debris where slugs hide by day
  5. Deadhead heavily after a budworm wave — petunias rebloom fast once the caterpillars are removed
  6. Protect beds from rabbits with a 2-foot fence of 1-inch mesh, or switch vulnerable spots to hanging baskets and tall planters
  7. If the plants are being destroyed faster than you can respond, have a local extension office or garden professional confirm the pest before any treatment is chosen

What not to do

  • Don't reach for a general insect spray expecting it to fix budworms — these caterpillars are resistant to many common contact insecticides, and killing them inside a closed bud is nearly impossible anyway; physical removal works better
  • Don't spray blooming petunias during the day; open flowers draw bees and butterflies, and daytime spraying hits them instead of the night feeders
  • Don't scatter slug bait where dogs or children play without confirming it's a pet-safe formulation — traditional metaldehyde baits are seriously toxic to pets
  • Don't squash every earwig on sight; in small numbers they eat aphids and other soft pests, and only nighttime petal damage justifies trapping them
  • Don't keep replanting the same spot after rabbit losses without adding a barrier — you're restocking their salad bar

Frequently asked questions

Why do my petunia buds have holes and never open?

That combination is the signature of the tobacco budworm, a small caterpillar that bores into unopened buds and eats the developing flower inside. The plant looks healthy but blooms stall out. Check at dusk with a flashlight and look for pepper-like droppings on leaves below the buds to confirm.

What eats petunias at night?

Most petunia feeders are nocturnal: tobacco budworms and earwigs come out at dusk, slugs and snails feed overnight in damp weather, and rabbits and deer typically visit between dusk and dawn. A flashlight inspection about an hour after sunset usually catches the culprit in the act.

Why isn't my bug spray stopping the caterpillars on my petunias?

Tobacco budworm populations across much of the US have developed resistance to several widely used contact insecticides, and a caterpillar feeding inside a closed bud is shielded from sprays regardless. That's why hand-picking at dusk and pinching off infested buds outperforms spraying for this particular pest in home plantings.

Will my petunias bloom again after being eaten?

Usually, yes. Petunias are vigorous rebloomers, and once the feeding stops — budworms removed, slugs controlled, or a barrier installed — new buds typically appear within a couple of weeks. Deadhead damaged blooms, trim leggy stems, and feed lightly to speed the recovery. Budworm pressure also drops naturally in fall.

Related yard clues

Plant Damage Flowers Eaten Overnight: Who Raided Your Garden Beds? Flowers that vanish overnight are most often deer or rabbits, and which flowers were taken narrows it fast — tulip and hosta blooms nipped off whole point to deer, while low plants clipped at a clean angle point to rabbits. Petals riddled with ragged holes but still attached usually mean earwigs or slugs working after dark, and shredded rose blooms are Japanese beetles feeding into dusk. Read the guide → Plant Damage What Is Eating My Roses? How to Identify the Culprit Rose bushes are most often eaten by Japanese beetles, rose slugs (sawfly larvae), aphids, leafcutter bees, deer, or rabbits — and each leaves a different signature. Lacy skeletonized leaves in midsummer point to Japanese beetles, translucent 'windowpane' patches in spring point to rose slugs, and cleanly clipped buds and stems point to deer or rabbits. Read the guide → Plant Damage Seedlings Disappearing Overnight: What's Taking Them? Seedlings that vanish overnight are usually felled by cutworms, eaten entirely by slugs, pulled up by birds, or clipped by rabbits — and sometimes they were killed by damping-off fungus rather than eaten at all. What's left behind decides it: a toppled stem means cutworms, slime trails mean slugs, a pinched wilted stem means fungus, and nothing at all usually means slugs or a bird. Read the guide → Plant Damage Plant Stems Cut Near the Ground: Cutworms or Rabbits? A seedling toppled with its stem severed right at the soil line is the classic signature of cutworms, night-feeding caterpillars that curl in the soil by day. Clean 45-degree cuts a few inches higher point to rabbits, while stems gnawed through at the base — often with the plant left uneaten — suggest voles or, less often, squirrels. Read the guide →

Still not sure? Compare with these clues

Bugs & Eggs Green Caterpillars on Plants: Which One Is Eating Yours? The green caterpillar on your plants is most likely a cabbage worm if it's on broccoli or kale, a tomato hornworm if it's large and has a tail spike, or a sawfly larva if it's on roses. Which plant is being eaten narrows it down fast, and handpicking plus row covers handle most of them — no spraying required. Keep in mind that some green caterpillars grow up to be butterflies worth keeping around. Read the guide → Plant Damage Holes in Hosta Leaves: Slugs, Earwigs, Hail, or Deer? Holes in hosta leaves are most often slug feeding — hostas are the slug's favorite plant in the American shade garden, and silvery slime trails confirm it. Earwigs chew similar ragged holes in hot dry spells, hail punches holes with bruised edges all on the same date, and deer skip the holes entirely and eat whole leaves down to the stalks. Read the guide → Plant Damage Leaves Chewed From the Edges: How to Read the Bite Marks Leaves eaten inward from the edges are usually caterpillars, grasshoppers, or — if the edges show neat crescent-shaped notches — adult weevils feeding at night. When whole leaf sections or stems are missing, the cut itself is the clue: a clean angled snip means rabbits, while ragged torn edges mean deer. Read the guide → Plant Damage What Is Eating My Tomato Leaves at Night? Tomato leaves that disappear overnight are most often the work of tomato hornworms, cutworms, slugs, or flea beetles — and if whole branches are gone, rabbits or deer. The size of the bites, whether there are slime trails, and how low on the plant the damage sits will point you to the culprit, and a ten-minute flashlight check after dark usually confirms it. Read the guide →