Hoya spots on leaves: causes and what to do
8 results in the diagnosis tree begin with spots on the leaves, 5 of them marked likely when the answers fit. They are ordered here for Hoya (Hoya carnosa), using what its sources say about light, soil moisture, humidity and pests and diseases and 2 problems recorded for it.
Sources last read 14 September 2026.
Hoya carnosa, the porcelain flower or wax plant, is a species of flowering plant in the family Apocynaceae, native to East Asia. It is a common house plant grown for its attractive waxy foliage, and sweetly scented flowers. Wikipedia, CC BY-SA 4.0
Native range: S. China to Laos, Japan (S. Kyushu) to Taiwan (subtropical). Also sold as fleshy-leaved wax flower, Honey Plant, porcelain flower, Porcelainflower and Wax Plant.
What Hoya’s sources say that bears on this
- Light
- High lightClemson Extension · read 11 September 2026Full sunRHS · read 11 September 2026
- Soil moisture
- Well-drainedRHS · read 11 September 2026
- Humidity
- Most foliage plants prefer more humidity than a heated room gives; succulents are named as an exceptionPenn State Extension · read 11 September 2026
- Pests and diseases
- Can be troubled by fungus gnats, mealybugs and banded greenhouse thrips.NC State Extension · read 13 September 2026Mealybugs can occur. Diseases: usually none.RHS · read 13 September 2026
How this shows up on a Hoya
Dry scorched spots after a move into a sunnier spot
On a hoya the marks are patchy and one-sided. Leaves on the shaded side of the plant keep their colour entirely.
Glass concentrates what would be tolerable outdoors, because it holds the heat and removes the moving air that carried it away. Its source describes full sun.
Telling it apart: Whether it followed a move or a season. Scorch appears within days of a change in position.
RHS · read 11 September 2026Translucent patches low on the plant
The tissue goes darker and slightly translucent, often at the point where the leaf meets the stem, and the hoya loosens in its compost.
The water a succulent stores is meant to last through dry spells. Kept in soil wetter than well-drained, it has no dry spell, and the saturated tissue collapses.
Telling it apart: Firm and wrinkled is thirst; soft and swollen is the opposite. The two look similar from across a room and feel nothing alike.
RHS · read 11 September 2026Possible causes, likeliest first for a Hoya
Most likely spider mites
Why: Spider mites feed on individual leaf cells, and each emptied cell shows as a pale speck.
What to try:
- Move the hoya away from other plants.
- Wash the leaves, top and underside, with a strong spray of water in a shower or sink.
What would settle it: Hold a sheet of white paper under a leaf and tap the leaf. Tiny specks that move across the paper are mites.
Most likely powdery mildew
Why: A white coating that wipes off is the surface growth of a fungus.
What to try:
- Remove the worst-affected leaves.
- Improve air movement around the hoya and space it away from others.
What would settle it: Wipe a patch. Powdery mildew comes away and leaves a yellowed patch beneath. White that does not wipe off is part of the leaf, or a mineral deposit from hard water.
Most likely thrips
Why: Thrips rasp the leaf surface and drink what leaks out, which leaves silvery, papery streaks.
What to try:
- Move the hoya away from other plants.
- Wash the leaves thoroughly and remove badly damaged ones.
What would settle it: Tap a leaf over white paper. Thrips are slender, fast-moving and about the size of a comma; they are easy to see once they are on paper.
Less likely for a Hoya, still possible
Questions
- What usually causes spots on the leaves on a Hoya?
- For Hoya: most likely spider mites, most likely powdery mildew and most likely thrips.
- How can I tell which one it is on my Hoya?
- What do the marks look like? Pale, dry, bleached patches on the side facing the window; Brown or black spots, many with a yellow ring around them; Tiny pale speckles all over, sometimes with fine webbing underneath; A white powdery coating that wipes off; Silvery streaks with tiny black dots; Dark, soft, water-soaked patches.
- What do Hoya's sources say about its light?
- Clemson Extension: High light. RHS: Full sun.
- What does this look like on a Hoya?
- On a hoya the marks are patchy and one-sided. Leaves on the shaded side of the plant keep their colour entirely. Telling it apart: Whether it followed a move or a season. Scorch appears within days of a change in position.
Other plants that show spots on the leaves
String of heartsTranslucent patches low on the plant
Aloe veraWashed-out patches that do not spread to the shaded side
Chusan palmBleached patches on the side facing the glass
Inch plantBleached patches on the side facing the glass
Polka dot plantWashed-out patches that do not spread to the shaded side
Ponytail palmDry scorched spots after a move into a sunnier spot
Something else wrong with the Hoya?
What this does not cover
This page orders a decision tree's results using a plant's sourced care. It has not seen your plant, its pot or its window, and two problems at once are common: that is the usual reason a confident answer turns out wrong. The questions in the diagnosis tool narrow it further than a list can.