Shrub · Nyctaginaceae
Bougainvillea
Bougainvillea spectabilis
Give it sun, restraint, and a touch of neglect, and bougainvillea fills a space with color.
Full sun
Every 7–14 days
USDA 9–11
15–40 ft · 4.6–12.2 m
Overview
Bougainvillea turns a plain courtyard wall or an arched entryway into something you slow down to look at. A woody, thorny climber out of South America, it can drape and reach 15 to 40 feet (4.6 to 12.2 m) across a sunny facade, or hold a tidy shape in a pot on a terrace. The color you catch from the street is not a bloom at all but a drift of papery bracts, the trait behind its paper flower name.
What gives bougainvillea its style appeal is that it performs best when life is a little hard on it. Pamper it like a fussy houseplant with rich soil, generous water, and constant feeding, and the result is a leafy green mound with barely any color to justify the space it takes. Hold back, hand it a baking spot and lean, dry footing, and the bracts come on strong across the warm season, just when a patio earns its keep.
It stays outdoors year-round only across USDA zones 9 to 11, where a hard freeze seldom arrives. In cooler regions a large container that can move to a sheltered porch or sunroom for winter is the answer, and since it grows quickly and takes the shears, it trains neatly along a trellis, gate, or balcony rail. The one thing it never lets you forget is its thorns, so keep heavy gloves close to the job.
Care
The short version: an all-day-sun position, fast-draining soil, and water only once the surface has dried. Feed sparingly, keep the nitrogen modest, prune once it has flowered, and shield it from frost.
Light
Bougainvillea asks for full sun, at least 6 hours a day, and rewards the brightest corner you can offer. A shaded position leads straight to a leafy plant that never colors up, because only strong light prompts it to form bracts, so reserve your most open, sun-drenched wall or terrace for it.
Water
Soak it well, then wait for the upper layer of soil to dry before the next drink, which tends to fall around every 7 to 14 days once it has settled in. It handles drought and in fact colors up more when kept fairly dry, whereas steady wetness trades bracts for foliage and risks root rot.
Soil
Give it well-drained sandy or loamy soil. A slightly acidic to neutral footing suits it best, somewhere between 6.0 to 7.0, and it will not tolerate a spot that holds water underfoot.
Temperature
Heat is its element, and it shrugs off readings across 30°F to 100°F (-1°C to 38°C). Frost is the one line it cannot cross, so any slide below freezing means sheltering it or shifting it indoors.
Humidity
Average air moisture is all it asks, with no figure you need to reach. Sun and dry footing at the roots matter to it far more than the dampness around a room or garden.
Feeding
Offer a monthly feed across spring through midsummer, using a balanced fertilizer set to half the usual rate. Hold the nitrogen down, since a rich diet drives foliage and starves the bracts you grew it for.
Pruning
Cut it back in late winter or early spring after flowering, saving any heavy reshaping for after the bloom period closes. Glove up with something thick first, since the thorns do not forgive a bare hand.
Repotting
Move it up a pot every 2 to 3 years or once it has outgrown its home. A tight, slightly pot-bound root ball actually coaxes more flowering, so there is no hurry to give it more room.
Size & spacing
Left to spread, it reaches 15 to 40 feet (4.6 to 12.2 m) tall with a spread to match, so a climbing plant deserves a firm wall or trellis behind it. Held in a container it stays much smaller, and dwarf cultivars are cut out for a snug spot.
When to plant
Bougainvillea lives for warmth and has no patience for frost. Move it outdoors in spring after the chill has truly gone, and it carries color across the warm months, even lingering toward winter where the season stays mild.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: after all danger of frost has passed in spring
- Harvest: spring through fall, sometimes into winter
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Nearly every bougainvillea complaint comes down to one of two looks: a plant with no color, or one dropping its leaves. Both point back to the setting it sits in far more than to any disease. Match the cues below against the way it is behaving, and tune the spot before a quiet sulk becomes a bare shrub where you wanted a full one.
Leaves and bracts falling all at once
A sudden shed nearly always follows a shock, most often a cold snap, a draft, or a move somewhere new. Chilled leaves and shoots take on a water-soaked look before they blacken. Keep it in one settled, warm, sunny place, water on a steady rhythm, and carry containers under cover before the reading nears 30°F (-1°C).
Fix:
- Protect from frost and bring containers indoors before temperatures fall below about 30 degrees F
- Keep the plant in a stable location and avoid moving it
- Maintain consistent watering, avoiding both drought and waterlogging
Yellow leaves with the veins still green
When new leaves pale to yellow while the veins keep their green, the plant struggles to take up enough micronutrients, often because the soil runs too alkaline or sits sodden. Hold it in slightly acidic, free-draining ground and let it dry out between drinks. To green the leaves again, mist on a micronutrient feed labeled for citrus or palms.
Fix:
- Maintain slightly acidic, well-drained soil
- Apply a foliar micronutrient spray suitable for citrus or palms
- Improve drainage and avoid keeping soil constantly wet
Plenty of green but hardly any color
A leafy plant showing no bracts nearly always means it has things too easy. Bougainvillea blooms when it is stressed, so ease off the water, set it where it gets at least 6 hours of full sun, and trim the nitrogen. A dry spell, even a root ball left a little cramped in its pot, will push it toward flower.
Fix:
- Move to or provide full sun (6 or more hours direct)
- Allow soil to dry out between deep waterings and reduce watering
- Stop high-nitrogen feeding; use a balanced fertilizer at a reduced rate
- Allow the plant to become slightly pot-bound or stressed to encourage blooming
Notched, chewed leaf margins and dark droppings
The culprit is the bougainvillea looper, an inchworm-style caterpillar that works after dark and scallops the leaf margins. Head out once it is dark to catch them mid-meal, then lift them off by hand. Where the count climbs, dose the young larvae with Bt or switch to spinosad, which takes out caterpillars young and grown.
Fix:
- Handpick caterpillars, checking at night when they feed
- Apply Bacillus thuringiensis (Bt) to control young larvae
- Apply spinosad, which controls both young and mature larvae
Toxicity
Reassuring for any home with pets or grazing animals: bougainvillea carries no recognized toxin, so a nibbled leaf will poison neither a cat, a dog, nor a browsing animal. The danger is a physical one. Stiff, sharp thorns run the length of the stems and can leave punctures, scratches, and at times dermatitis, while the sap can irritate delicate skin, so reach for heavy gloves before you handle it.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Nothing here is chemically toxic, so a inquisitive cat taking a taste comes to no harm. The real danger is the rigid thorns, which can rake a paw or face, so set a potted one out of reach of a jumping cat indoors.
Dogs None
Dogs are fine in its company, and a mouthful of leaf will not poison them. One nosing its way through the canopy may snag on a spine, so look out for a stray scratch or jab rather than sickness.
Horses Safe
Browsing this plant leaves a horse unharmed. Only the sharp spines warrant caution, as a horse pressing in among the branches may pick up a jab.
Rabbits Safe
Rabbits can crop the leaves with no risk of poisoning. Keep the prickly stems away from a small pet, where one spine might do serious harm to delicate skin or an eye.
Livestock Safe
Cattle, goats, and sheep run no toxic risk from it. Mind the woody thorns instead, which can rake hide or muzzle as the animals push in to feed.
Birds Safe
Birds roost and build nests in it unharmed, with no toxin to fret over. Those dense, prickly branches even give smaller birds dependable cover.
People Safe
No one gets poisoned by the plant, but the thorns are a different story. A puncture or scratch can trigger dermatitis or, on rare occasions, a skin infection, while the milky sap can bother delicate skin, so pull on thick gloves before any pruning or handling.
Not chemically poisonous, but the plant has sharp woody thorns/spines that cause puncture wounds and scratches (rarely skin infection or dermatitis), and the sap may cause mild skin irritation in sensitive people. The physical thorns are the real hazard, not chemical poisoning. Wear heavy gloves when pruning or handling.
Varieties
Bougainvillea offers a broad range of colors and scales, from grand climbers for a wall to dwarf forms suited to a planter by the door. These are the names you are most likely to meet when choosing for a space.
Barbara Karst
An energetic grower that pushes out heavy flushes of bracts in vivid red to magenta.
San Diego Red
A well-loved large red cultivar valued for just how freely it flowers.
Raspberry Ice
A compact choice pairing variegated foliage with rose-red bracts.
California Gold
Notable for its warm yellow-to-gold bracts rather than the usual pinks and reds.
Pixie
A dwarf, naturally tidy form that suits a container nicely.
Helen Johnson
A dwarf, compact cultivar that thrives in containers and baskets hung up high.
How to propagate
Making more bougainvillea is simple enough if you are willing to wait, and the surest path is to clone one you already grow rather than begin from seed.
Stem cuttingsModerate
Summer · Several weeks to a few months
The everyday route to extra plants is a summer cutting. Take a piece of this year's growth, bed it in a mix of sand and peat, and wait it out, as rooting can run anywhere from a few weeks to a few months.
LayeringModerate
Growing season · Several weeks to months
Layering suits the active part of the year: bend a low stem down and pin it to root while still fed by the parent. Reckon on several weeks to months before that section holds enough roots to be cut loose.
SeedDemanding
Warm season · Slow and variable
Seed is doable in the warm season yet slow and hard to predict, and the seedlings rarely come true to the parent. For that reason, named cultivars almost always come from cuttings or layers.
Myths
The bright papery color on a bougainvillea comes from its flowers.
The colored papery petals are in fact modified leaves called bracts, not blooms in any sense. The genuine flowers are the small white-to-cream tubes seated at the center of every cluster, simple to overlook beneath so much color.