Why Plants Die
Theme

Cape leadwort

Plumbago auriculata, Plumbaginaceae

Sources last read 14 September 2026.

Middling It gives warning, with time to act.

Also called Cape plumbago.

Cape leadwort (Plumbago auriculata), the whole plant.
Dguendel, CC BY 3.0 · Wikimedia Commons

Cape leadwort is toxic

  • Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Toxic to people. Irritates skin. Use gloves and protective gear when handling it. RHS

What the sources say about its care

Light
Full sun
RHS · read 13 September 2026
Water
Well-drained
RHS · read 13 September 2026
Humidity

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

ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%
Penn State Extension · read 13 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 13 September 2026
Soil
Chalk, Loam, Sand; pH Acid or Alkaline or Neutral
RHS · read 13 September 2026
Toxic to cats
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Toxic to dogs
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Harmful to people
Irritates skin. Use gloves and protective gear when handling it.
RHS · read 13 September 2026

How it usually goes wrong

Crisp margins that appear in winter

The cape leadwort shows browning on many leaves at once, all at the margin, with no spots or soft patches anywhere.

The edges fail first because they are the end of the plumbing. Penn State Extension cites 30% to 60% as the recommended indoor range, and winter heating regularly takes a room under it.

Telling it apart: Whether the damage advances. Dry air marks a leaf and stops; rot keeps going.

Penn State ExtensionCape leadwort brown leaf tips and edges: causes
Dry scorched spots after a move into a sunnier spot

The damage on the cape leadwort faces one way. Turn the pot round and the other side is clean.

Nothing here disputes the full sun its source names. The damage comes from the change: foliage formed in lower light is thin, and a sudden move into direct sun bleaches it faster than tougher growth can replace it.

Telling it apart: Whether it appeared after a move. Scorch follows a change in position within days.

RHSDiagnose spots on the leaves on this Cape leadwort
Leaves but no flowers

The cape leadwort flowered well at first, then less each season, while its leaves stayed healthy and new stems grew longer.

Its source places it in full sun. Flowers cost more than leaves, and a plant kept darker than that keeps growing leaves while it builds few buds or none.

Telling it apart: The spacing of the newest leaves. Stretched growth means the light is short; normal spacing points at timing or feeding.

RHSDiagnose no flowers or dropped buds on this Cape leadwort
Wrinkling rather than yellowing

The plant droops as a whole rather than losing particular leaves, and the soil surface has gone pale and hard.

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: Whether the soil has pulled from the pot wall. That gap is the mark of soil taken properly dry.

RHSCape leadwort leaves turning yellow: causes

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

Routine care

Watering
Give container plants little water in winter.
NC State Extension · read 13 September 2026
Under glass, give full light and use a peat-free compost that is loam-based; water generously during growth and feed monthly with a balanced liquid fertiliser.
RHS · read 13 September 2026
Feeding
Under glass, keep in full light in a loam-based, peat-free compost; water generously during growth and give a balanced liquid fertiliser each month.
RHS · read 13 September 2026
Repotting
While dormant, keep only just moist; in spring, top-dress or repot.
RHS · read 13 September 2026
Propagation
Seed
NC State Extension · read 13 September 2026
In spring sow seed at 13-18°C, or in mid-summer take semi-hardwood cuttings with bottom heat.
RHS · read 13 September 2026
Pruning
In early spring, pruning group 12.
RHS · read 13 September 2026
Pests and diseases
Can be troubled by glasshouse whitefly and glasshouse red spider mite. 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

Plumbago auriculata, the Cape leadwort, blue plumbago or Cape plumbago, is a species of flowering plant in the family Plumbaginaceae, native to South Africa and Mozambique.

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

Native range
Mozambique to S. Africa
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Mozambique to South Africa
NC State Extension · read 13 September 2026
S Africa
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
scrambling shrub
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Annual, Herbaceous Perennial, Perennial, Shrub, Vine; habit arching, mounding, rounded
NC State Extension · read 13 September 2026
Climbing, Bushy (evergreen)
RHS · read 13 September 2026
Size
Height 72–180 in; width 72–96 in
NC State Extension · read 13 September 2026
Height 2.5-4 metres; spread 1-1.5 metres after 5–10 years
RHS · read 13 September 2026
Flowering
Flowers blue, pink, white; blooms in fall, summer
NC State Extension · read 13 September 2026
Flowers blue in summer and autumn
RHS · read 13 September 2026

Common problems with Cape leadwort

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.