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Hibiscus

UF/IFAS advises scouting hibiscus regularly for aphids, whiteflies and mealybugs, which are usually found in clusters on the leaves and flower buds. Turn the leaves over, or look for the black sooty mould that grows on their honeydew. UConn also lists hibiscus as a host for greenhouse whitefly and citrus mealybug under glass.

Tropical hibiscus is sensitive to cold. UF/IFAS says the slightest cold wave can yellow and drop its lower leaves, and in north Florida it freezes to the ground. Outside frost-free areas a potted plant spends the winter indoors or under glass, and that move is when pests hitch a ride: check the plant and its pot before it comes inside.

crop context · tropical hibiscus in a pot

The pests on hibiscus

SUMMER–FALL PEAK

Melon aphid

Colonies under the leaves and on buds. It is not slowed by hot weather and resists several insecticides.

ReleaseAphidius colemani0.25–4 /m² per release indoors or under glass
LATE SUMMER PEAK

Silverleaf whitefly

Tiny yellowish-white adults under the leaves; honeydew and sooty mould. A pest of warm regions and warm glass.

ReleaseEretmocerus eremicus1–10 /m² per release, weekly, three or more

Season calendar

POTTED HIBISCUS · OUTDOORS IN SUMMER · QUALITATIVE
JFMAMJJASOND
AphidsJan: QuietFeb: QuietMar: QuietApr: BuildingMay: BuildingJun: BuildingJul: Pest pressure highAug: Pest pressure highSep: Pest pressure highOct: Pest pressure highNov: BuildingDec: Quiet
WhitefliesJan: QuietFeb: QuietMar: QuietApr: QuietMay: BuildingJun: BuildingJul: Pest pressure highAug: Pest pressure highSep: Pest pressure highOct: Pest pressure highNov: BuildingDec: Quiet
Mealybugs & scale (all year indoors)Jan: Pest pressure highFeb: Pest pressure highMar: Pest pressure highApr: Pest pressure highMay: Pest pressure highJun: Pest pressure highJul: Pest pressure highAug: Pest pressure highSep: Pest pressure highOct: Pest pressure highNov: Pest pressure highDec: Pest pressure high
Pests carried in when it comes insideJan: QuietFeb: QuietMar: QuietApr: QuietMay: QuietJun: QuietJul: QuietAug: QuietSep: Pest pressure highOct: Pest pressure highNov: QuietDec: Quiet
Release window (indoors or under glass)Jan: QuietFeb: QuietMar: QuietApr: QuietMay: Release windowJun: Release windowJul: Release windowAug: Release windowSep: Release windowOct: QuietNov: QuietDec: Quiet

Starter program

Outdoors, leave the wild parasitoids and predators to work, and use soap or oil on the first clusters. Releases make sense on a hibiscus in a conservatory, sunroom or greenhouse, where the insects cannot fly off.

  1. EVERY WEEKScout leaves and budsFlip the leaves and check the flower buds for clusters of aphids, whiteflies or mealybugs, and look for sooty mould.
  2. FIRST CLUSTERSInsecticidal soap or horticultural oilUF/IFAS says early infestations are easily controlled this way. Cover the leaf undersides and repeat as the label allows.
  3. APHIDS, UNDER GLASSAphidius colemani0.25–4 /m² per release, at least three releases, starting early before aphids build up. Keep ants off the plant.
  4. WHITEFLY, UNDER GLASSEretmocerus eremicus1–10 /m² per release, weekly, at least three releases; needs a 68 °F (20 °C) daily average.

Setting up indoors

UF/IFAS says these pests are easily controlled if caught early, so the setup is about seeing them early.

Never use malathion on hibiscus

UF/IFAS warns against it specifically. Check any product label for hibiscus before spraying.

Inspect before bringing it in

Pests on a plant that summered outside can come in on the leaves or through the drainage holes. Quarantine it from other houseplants.

Keep ants off

Ants tend aphids and mealybugs for their honeydew and protect them from natural enemies.

Watch the rose of Sharon nearby

In the north, melon aphid overwinters as eggs on rose of Sharon, a hardy hibiscus, so spring aphids can start there.