lesser bougainvillea

Watering

Lesser bougainvillea (Bougainvillea glabra) is a drought-tolerant vine that stores water in its woody stems and fleshy roots, so it prefers to dry out between drinks. Let the top 5 cm of soil dry completely, then water deeply until it runs out of the drainage holes. Empty any saucer within 15 minutes. Water less in winter, when growth slows and soggy roots can rot quickly. Indoors, it needs more frequent watering only during the bright growing season.

Does it need water today?

Push a finger 5 cm into the soil. If it feels dry and crumbly, water it. If it feels cool or damp, wait. Lift the pot too: a light pot means it is thirsty, a heavy pot means it can wait. Leaves that droop slightly in the afternoon, then perk up by evening, are normal and not a sign of thirst.

Bougainvillea blooms best when it is slightly stressed for water in the growing season. Don't keep the soil constantly moist, or you will get lush leaves and few of the colourful bracts.

Sunlight

Lesser bougainvillea needs strong, direct sun to produce its papery, colourful bracts. In full sun it grows compact and flowers heavily. In partial shade it becomes leggy, with long stems and few flowers. Indoors it struggles, so give it the brightest spot you have and move it outdoors when nights stay above 10°C.

• Ideal: Full sun · 6-8 hours of direct sun
• Tolerates: Full sun, Partial sun
• Best spot in a room: At the window
• Artificial light: If grown indoors, use a full-spectrum grow light at 15 to 30 cm above the canopy for 12 to 14 hours a day during the growing season. Rotate the pot every week so growth stays even.

Temperature

Lesser bougainvillea (Bougainvillea glabra) is a tropical to subtropical vine that thrives in warmth and sun. It stops growing below about 15°C and is damaged by frost, so keep it above 5°C in winter. Night temperatures of 15°C or higher suit it best, and it flowers most strongly when days are hot and nights are cool but not cold.

• Ideal: 15–30 °C
• Tolerates: 2–38 °C
• Hardiness zones: 10-12

Fertilizing

Lesser bougainvillea flowers best when it is slightly underfed on nitrogen. Too much nitrogen produces lush green leaves and few bracts. Phosphorus and potassium support flowering, so choose a fertilizer with more of those nutrients than nitrogen. Water the plant before applying any fertilizer to avoid burning the roots.

• Slow-release fertilizer: Apply once a year in early spring, just as new growth begins. Bougainvillea grows in poor soil and does not need much feeding.
• Low-nitrogen, high-phosphorus flowering plant fertilizer (for example, a 5-10-5 or 10-20-10 formula), Bone meal or rock phosphate for slow phosphorus supply, Slow-release granular fertilizer formulated for flowering shrubs and vines

Soil

Lesser bougainvillea needs soil that drains freely and never stays soggy. Its roots rot quickly in heavy, wet, or compacted soil, so drainage matters more than fertility. A slightly sandy, gritty mix that dries out between waterings is ideal.

• Fast-draining potting mix: Two parts peat-free potting mix, one part perlite or pumice, and one part coarse sand or horticultural grit
• Cactus or succulent mix: Commercial cactus mix, lightly amended with extra perlite to hold a little moisture while still draining quickly
• Garden bed soil (in-ground): Native or sandy loam mixed with compost and coarse sand where drainage is poor; raised beds are recommended in wet areas
• pH 6–7.5

Repotting

Repot in warm weather, when the plant is actively growing and temperatures stay above 18°C. Lesser bougainvillea has thin, brittle roots that dislike disturbance, so handle the root ball gently and avoid tearing it apart.

• How often: Every 2-3 years, or when roots fill the pot and water runs straight through
• New pot: Move up only 2-5 cm in diameter at a time; choose a pot with drainage holes. Bougainvillea glabra prefers to be slightly root-bound, so oversized pots hold wet soil and invite root rot.
• Repotting season: Spring, Summer

How to repot

1. Tip the plant on its side and ease it out of the old pot, supporting the stems with one hand
2. Gently loosen the outer roots with your fingers; trim away any dead, black, or mushy roots with clean shears
3. Place a 3-4 cm layer of fresh mix in the new pot, then set the plant so the root ball sits at the same depth it grew before
4. Fill around the root ball with fresh mix, firming lightly with your hands to remove large air pockets
5. Water thoroughly until it drains from the holes, then leave the pot in bright, sheltered light

Pruning

Bougainvillea glabra blooms best when it is slightly root-bound and gets full sun, and it flowers on new wood. Prune hard in late winter or early spring, before the new growth begins, then lightly trim during the growing season to shape the plant and encourage repeat flowering. Always wear gloves, because the thorns are sharp.

Pruning season: Winter, Spring

How to prune

1. In late winter, remove all dead, diseased, or damaged wood first, cutting back to healthy tissue.
2. Cut out any thin, weak, or crossing stems at their base to open up the center of the plant.
3. Shorten the remaining main canes by about one-third to one-half, cutting just above an outward-facing node or bud.
4. For a container plant, cut back long shoots to keep the size manageable, and trim the top to maintain a compact shape.
5. During the growing season, pinch or snip back long, unruly shoots after each flush of bloom to encourage branching and more flowers.
6. Avoid heavy pruning in autumn, as new growth may not harden off before cold weather arrives.
7. Clear fallen leaves and debris, and dispose of any cuttings from diseased plants rather than composting them.

Propagation

Bougainvillea glabra is one of the easier bougainvilleas to root from softwood tips, but it roots slowly and dislikes soggy soil. Keep the medium just barely moist, never waterlogged, and be patient: the cutting may look unchanged for several weeks before roots form. Once rooted, let the young plant get plenty of sun so it blooms well in its first season.

About lesser bougainvillea

Also known as: Lesser bougainvillea, Paperflower, Bougainvillier glabre

• Plant type: climber, shrub, woody vine
• Lifespan: perennial
• Distribution: Native to south-eastern Brazil and adjacent parts of South America.
• Mature height: Up to 5-10 m when climbing, often kept at 2-3 m in gardens
• Bloom time: Mainly late winter to summer in the Northern Hemisphere, and in warm climates across much of the year

Pets · People

Pets: Mildly toxic · People: Mildly toxic. The sap and leaves can irritate the mouth and stomach if chewed, causing mild gastrointestinal upset; the thorns can also cause scratches. Keep out of reach of curious pets and children.

Common problems

• No flowers: Usually caused by too little sun, too much nitrogen fertiliser, or overwatering; move to a sunnier spot and switch to a bloom feed.
• Yellowing leaves: Often from waterlogged soil or poor drainage, leading to root stress; let the soil dry more between waterings and check the pot has drainage holes.
• Leaf drop after cold: Sensitive to temperatures below about 10 °C; cold snaps cause leaf loss, so protect young plants in winter.
• Mealybugs and scale: White cottony clusters on stems and leaf joints; wipe off with alcohol on a cotton swab or treat with horticultural oil.
• Aphids on new growth: Soft tips attract aphids in spring; rinse them off with water or use insecticidal soap.

Uses

Mainly ornamental, grown as a climber on walls, fences and pergolas, in hanging baskets, and as a clipped hedge or bonsai in warm regions. In parts of South America its wood and bracts have been used in local folk remedies, though these uses are not well documented.

Is it edible?

Not edible; the sap and leaves are irritating if eaten.

History & legends

Bougainvillea was first described in Europe in the late eighteenth century after botanists collected specimens from South America, and was named for the French explorer Louis Antoine de Bougainville. Many stories attach to the plant as it spread through tropical gardens, and it became a symbol of Mediterranean and tropical gardens alike.

Did you know?

The colourful parts are bracts, leaf-like modified structures, not petals; the actual flowers are tiny and white, tucked inside each cluster of three bracts.

Frequently asked questions

How this guide was written

Verdiss writes each guide with AI from botanical references and checks the species against iNaturalist and Plants of the World Online (Kew). Readers can rate every guide in the app.

Sources

• iNaturalist
• Plants of the World Online (Kew)
• Wikipedia