Bougainvillea leaves turning yellow: causes and what to do
17 results in the diagnosis tree begin with yellowing leaves, 7 of them marked likely when the answers fit. They are ordered here for Bougainvillea (Bougainvillea glabra), using what its sources say about soil moisture, light, soil, watering and feeding and 2 problems recorded for it.
Sources last read 14 September 2026.
Bougainvillea glabra, the lesser bougainvillea or paperflower, is the most common species of bougainvillea used for bonsai. The epithet 'glabra' comes from Latin and means "bald". Wikipedia, CC BY-SA 4.0
Native range: E. & S. Brazil (wet tropical). Also sold as Lesser Bougainvillea, Paper Flower and Paperflower.
What Bougainvillea’s sources say that bears on this
- Soil moisture
- Moist but well-drainedRHS · read 11 September 2026
- Light
- Full sunRHS · read 11 September 2026
- Soil
- Loam; pH Acid or Alkaline or NeutralRHS · read 11 September 2026
- Watering
- Lesser Bougainvillea suits a hot, dry climate; water it thoroughly but let it dry out between waterings.NC State Extension · read 13 September 2026From spring, as plants resume active growth, water more and use a balanced liquid feed until colour shows in the bracts, then change to a high potassium feed. In autumn, water less and stop feeding.RHS · read 13 September 2026
- Feeding
- From spring, as active growth resumes, water more and give a balanced liquid feed until colour shows in the bracts, then change to a high-potassium feed. In autumn, water less and stop feeding.RHS · read 13 September 2026
How this shows up on a Bougainvillea
Lower leaf blades collapse and yellow within days of a watering
A sour smell from the compost is common on a bougainvillea, and the leaves nearest the soil come away when pulled. The surface may look dry while everything beneath it is not.
The source for this plant describes moist but well-drained soil. Compost that stays saturated loses the air spaces fine roots grow into, and those roots die back first.
Telling it apart: Weigh the pot in your hand. A pot still heavy a week after watering is holding more water than the roots are using.
RHS · read 11 September 2026Pale dry areas across the upper leaf blades only
Affected tissue goes pale and then papery, and the boundary follows where the light falls rather than the shape of the leaf blade.
Full sun is what its source names, and outdoors that sun comes with moving air that cools the foliage. Behind still glass the same light heats the tissue well above the room, and the exposed patches dry out first.
Telling it apart: Which side. Damage confined to the lit side is light; damage spread evenly is not.
RHS · read 11 September 2026Possible causes, likeliest first for a Bougainvillea
Most likely too little water
Ranked higher because Bougainvillea's recorded problems point this way.
- Moist but well-drained RHS · read 11 September 2026
Why: Soil dry two inches down, under lower leaves that are yellowing or leaves that are falling, is a bougainvillea shedding what it cannot support.
What to try:
- Water until it runs from the drainage hole, then let the pot drain.Useful: pot with drainage holes
- If the water runs straight through a shrunken rootball, stand the pot in water for twenty minutes so the compost can take it up.
What would settle it: Water it thoroughly and look again the same evening. A thirsty plant firms up fast. One that does not has a root problem rather than a water problem.
Most likely too little water
Ranked higher because Bougainvillea's recorded problems point this way.
- Moist but well-drained RHS · read 11 September 2026
Why: Soil dry two inches down leaves the roots nothing to send up, and the leaf edges are the last tissue in line.
What to try:
- Water thoroughly, until it runs from the drainage hole.Useful: pot with drainage holes
- Check the soil with a finger every few days rather than watering on a fixed day.Useful: moisture meter
What would settle it: Water it thoroughly and watch the next new leaves. If they come in with clean edges under steadier watering, the edges were thirst.
Most likely not enough light
Ranked higher for Bougainvillea because of what its sources say.
Its sources place this plant in full sun or high light, which makes a shortage of light a strong explanation indoors.
- Full sun RHS · read 11 September 2026
Why: Far from a bright window, a bougainvillea builds leaves it cannot afford.
What to try:
- Move it closer to the brightest window you have, over a week or two rather than in one step.Useful: grow light
- Water less while it is in low light; a bougainvillea that is barely growing uses little.
What would settle it: Compare a new leaf with one from last year. Smaller and paler, with a longer gap below it, is the reaching pattern rather than a nutrient one.
Less likely for a Bougainvillea, still possible
- Most likely short of nutrients
- Most likely too much water
- Most likely a build-up of salts in the soil
- Most likely cold
- Nutrients are an unlikely explanation here
- Possibly root rot, in a pot that has stopped draining
- Light and feeding are both plausible, and this does not separate them
- Possibly too much direct sun
- Possibly too much direct sun, or feeding
- This may be ordinary leaf loss
- Probably too much water, but this is not settled
- Possibly dry air
- Probably too much water
- The answers do not point at one cause
Questions
- What usually causes yellowing leaves on a Bougainvillea?
- For Bougainvillea: most likely too little water, most likely too little water and most likely not enough light.
- How can I tell which one it is on my Bougainvillea?
- Where is the yellowing? The lowest leaves, working upward; New growth at the top, while older leaves stay green; Between the veins, the veins themselves still green; At the leaf tips and edges, browning as it goes; Patchy, only on the side facing the window.
- What do Bougainvillea's sources say about its soil moisture?
- RHS: Moist but well-drained.
- What does this look like on a Bougainvillea?
- A sour smell from the compost is common on a bougainvillea, and the leaves nearest the soil come away when pulled. The surface may look dry while everything beneath it is not. Telling it apart: Weigh the pot in your hand. A pot still heavy a week after watering is holding more water than the roots are using.
Other plants that show yellowing leaves
AlocasiaThe crown yellows from below and the pot stays heavy
Arrowhead plantNew leaf blades arrive smaller and paler than the ones below
Asparagus fernPale, undersized fronds at the tips of the stems
Baby rubber plantYellowing that begins at the lowest leaves
Baby's tearsYellow, limp leaves at the base
Bird's nest fernYellowing that begins at the outermost blades
Something else wrong with the Bougainvillea?
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.