Why Plants Die
Theme

Hoya

Hoya carnosa, Apocynaceae

Sources last read 14 September 2026.

Forgiving Among the more tolerant plants here.

Also called fleshy-leaved wax flower, Honey Plant, porcelain flower, Porcelainflower and Wax Plant.

Hoya (Hoya carnosa), the whole plant.
Daderot, CC0 · Wikimedia Commons

Toxicity is partly unassessed

  • Listed as non-toxic to cats by ASPCA.
  • Listed as non-toxic to dogs by ASPCA.
  • Not assessed for people. RHS publishes no harm statement for this plant. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.

What the sources say about its care

Light
High light 150–1000 fc
Clemson Extension · read 11 September 2026
Full sun
RHS · read 11 September 2026
Water
Well-drained
RHS · read 11 September 2026
Humidity

No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.

Most foliage plants prefer more humidity than a heated room gives; succulents are named as an exception
Penn State Extension · read 11 September 2026
Temperature

How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.

H2 — 1–5°C 1–5 °C
RHS · read 11 September 2026
Soil
Chalk, Loam, Sand; pH Acid or Alkaline or Neutral
RHS · read 11 September 2026
Toxic to cats
Listed as non-toxic
ASPCA · read 11 September 2026
Toxic to dogs
Listed as non-toxic
ASPCA · read 11 September 2026
Harmful to people
No harm statement is published for this plant; that absence is not evidence it is safe.
RHS · read 11 September 2026

How it usually goes wrong

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.

RHSHoya spots on leaves: causes
Translucent 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.

RHSHoya spots on leaves: causes
Wrinkling rather than yellowing

The hoya loses its stiffness first at the tips of the newest growth, and the whole pot feels light for its size.

Water held in the cells keeps a leaf rigid. With the compost dry beyond what its source describes as well-drained, that water is used and not replaced.

Telling it apart: How fast it recovers. A thorough watering lifts a thirsty plant within hours; roots that are damaged do not respond.

RHSDiagnose yellowing leaves on this Hoya

Not sure which it is? Ask the diagnosis questions for Hoya.

Routine care

Watering
Let the soil dry between waterings. This plant can be shocked by cold water.
NC State Extension · read 13 September 2026
Repotting
Move the wax plant to a new pot once it outgrows the old one, but not while it is budding or flowering.
NC State Extension · read 13 September 2026
Propagation
Wax plant can be propagated by stem cuttings.
NC State Extension · read 13 September 2026
Increase by layering or from semi-hardwood cuttings.
RHS · read 13 September 2026
Pruning
If pruning is needed, do it in early spring before fast growth starts. Leave the peduncle (“spur”) that carried flowers, as it flowers again and again over several years.
NC State Extension · read 13 September 2026
Pests and diseases
Can be troubled by fungus gnats, mealybugs and banded greenhouse thrips.
NC State Extension · read 13 September 2026
Mealybugs can occur. Diseases: usually none.
RHS · read 13 September 2026

Move something and watch

Loading the simulator. It needs JavaScript; the care table above does not.

About the plant

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. It is grown well in pots and hanging baskets.

From Wikipedia, CC BY-SA 4.0 · read 13 September 2026

Native range
S. China to Laos, Japan (S. Kyushu) to Taiwan
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Southeast Asia, Japan, and Taiwan
NC State Extension · read 13 September 2026
C China to Australia
RHS · read 13 September 2026
Climate
subtropical
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Growth form
climbing epiphyte or lithophyte
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Epiphyte, Vine; habit climbing
NC State Extension · read 13 September 2026
Climbing (evergreen)
RHS · read 13 September 2026
Size
Height up to 120 in
NC State Extension · read 13 September 2026
Height 4-8 metres; spread 1-1.5 metres after 10–20 years
RHS · read 13 September 2026
Flowering
Flowers pink, white; blooms in fall, spring, summer
NC State Extension · read 13 September 2026
Flowers pink in spring, summer and autumn; red in spring, summer and autumn; white in spring, summer and autumn
RHS · read 13 September 2026

Common problems with Hoya

Other Hoya

More of the Apocynaceae family

Plants with similar care

Sources

What this does not cover

The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.

Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.

If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.