Blue passion flower 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 Blue passion flower (Passiflora caerulea), 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.
Passiflora caerulea, the blue passionflower, bluecrown passionflower or common passion flower, is a species of flowering plant in the family Passifloraceae. It is native to South America and has been introduced elsewhere. Wikipedia, CC BY-SA 4.0
Native range: Bolivia to Brazil and N. Argentina (subtropical). Also sold as blue crown, Blue Passionflower, Bluecrown Passionflower, common passion flower, Common Passionflower and flower of five wounds.
What Blue passion flower’s sources say that bears on this
- Light
- Full sun, Partial shadeRHS · read 13 September 2026
- Soil moisture
- Moist but well-drained or Well-drainedRHS · read 13 September 2026
- Humidity
- ASHRAE recommends indoor relative humidity between 30% and 60%Penn State Extension · read 13 September 2026
- Pests and diseases
- Can be troubled by barnacle scale, plus the phlox plant bug and related Lopidea plant bugs.NC State Extension · read 13 September 2026In a greenhouse, scale insects, mealybugs, greenhouse whitefly and greenhouse red spider mite can occur. Diseases: a virus and, rarely, honey fungus.RHS · read 13 September 2026
How this shows up on a Blue passion flower
Bleached patches on the side facing the glass
On a blue passion flower the scorch appears within a few days of a sunny spell or a move, and it does not spread afterward.
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, partial shade.
Telling it apart: Whether it followed a move or a season. Scorch appears within days of a change in position.
RHS · read 13 September 2026Pale patches in rings or streaks that do not spread like a spot
The blue passion flower grows slowly, with mottled, puckered leaves and sometimes streaked flowers.
RHS lists viruses among the diseases it may get. Plant viruses are spread by sap-feeding insects such as aphids and on cutting tools, and there is no cure once a plant is infected.
Telling it apart: Whether it spreads like a spot. Virus patterns do not enlarge into dead patches the way leaf spots do.
RHS · read 13 September 2026Possible causes, likeliest first for a Blue passion flower
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 blue passion flower 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 blue passion flower 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 blue passion flower 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 Blue passion flower, still possible
Questions
- What usually causes spots on the leaves on a Blue passion flower?
- For Blue passion flower: spider mites, powdery mildew and thrips.
- How can I tell which one it is on my Blue passion flower?
- 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 Blue passion flower's sources say about its light?
- RHS: Full sun, Partial shade.
- What does this look like on a Blue passion flower?
- On a blue passion flower the scorch appears within a few days of a sunny spell or a move, and it does not spread afterward. 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
African violetFuzzy gray growth over spreading patches on leaves and stems
Barberton daisyDark spots with a yellow halo spreading across the leaves
Bearded irisFuzzy gray growth over spreading patches on leaves and stems
Bigleaf hydrangeaBrown or black spots on the leaves that grow and merge
Busy LizzieAngular pale patches and a downy coating on the undersides
Calla lilySilvery patches dotted with tiny black spots: thrips
Something else wrong with the Blue passion flower?
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.