There are at least four and as many as 15 species of Bougainvillea, depending on what source you believe. Most Bougainvilleas grown in cultivation are cultivars/hybrids of two of the three primary species available in cultivation. Bougainvillea spectabilis can reportedly be identified by its woolly, rounded leaves, large curved thorns and ovoid bracts of reds and purples. Bougainvillea glabra is a smaller-branched and leaved plant with less thorns and less overall size, and perhaps with less color options (usually magentas or purples). Bracts are triangle-shaped, similar to hybrids 'Ms Alice' and 'Sillhouette' (see below) . Thorns are said to be short, thin and curved. However, I can find no photos of these two pure species to see what ‘large and short' actually mean. Bougainvilla peruviana is a much less commonly encountered species, and is supposedly a very open, non-dense vine with greenish bark and roundish bracts of various magenta hues. Thorns are thin and straight to somewhat curved in old plants. Leaves are thinner and narrower, almost lancelote. There is a relatively new species in cultivation known as the tree bougainvillea, Bougainvillea arborea. This plant does not vine but actually forms a real tree trunk (solitary) and tends to have only varieties with lavender bracts. The flowers of this species have a nice smell (the other species have odorless flowers).
Bougainvillea arborea photos (left by jnana and right by islandplumeria)
Obviously any cultivated plants with bract colors other than red or purple are hybrids as none of the above species come in those colors. The actual origins or species mixes that have been used to create today's cultivated hybrids is often unclear, so most hybrids are not assigned species names.
Bract colors not normally encountered in nature. Right photo shows a bit of 'natural' color appearing as pink splotch on this hybrid
Sometimes plants are grown for their variegated leaves as well as beautiful bracts (plant in my yard)
This vine is native to Brazil but it is grown all over the world in the tropics and warm temperate zones (down to about USDA zone 9b). In most areas it is an evergreen, but in marginal climates it may be deciduous. It also tends to have a ‘down' time in winters when it may not flower at all or as well as it does the rest of the year. If it freezes and gets badly damaged, but the roots survive, it may regrow year after year. In colder areas it makes a good potted plant and can be brought indoors in colder months. It does not, however, make a good house plant. Its demands for very bright light keep it from surviving indoors, in addition to most species being heavily thorned. In hot, arid climates, it may not flower well during the midsummer seasons, perhaps due to low humidity, or decreased water available to the roots.
Bougainvillea growing in the tropics along a salt water inlet (Hawaii) left photo; right photo leafless and flowerless in winter in my yard
Though they are probably best known for their famous colorful displays throughout the Mediterranean climates of the world, they grow very well in most tropical, wet climates as well, though perhaps not quite as gloriously. Climates with lots of sun seem to produce the best looking plants so climates with huge amounts of rainfall may not support as much dazzling color as is seen in the drier, sunnier subtropical climates of the world. However, some humidity is needed to stimulate flowering activity, so extremely arid climates may not be the best for color displays, either. Blooming occurs year round in most tropical climates, but in more seasonal locations (like in Southern California) blooming is most prolific in spring and fall.
Brilliant display in front of a Los Angeles home
Bougainvilleas are grown primarily for their amazing and brilliantly colored carpals. The flowers of this plant are nearly all white or cream colored and fairly insignificant, but each flower is surrounded by several (usually 3) sets of carpals of a wide range of colorful, papery carpals one can see for miles- some colors are so brilliant they seem to emit their own light and can be hard to photograph (the brilliance is often lost in translation). The colors range from a dark purple, through all the pinks and reds, into oranges and some yellows to white. The leaves of some hybrids are beautifully variegated making these forms even more spectacular.
All the color in these photos is the bracts, while the flower are the tiny white centers
fairly wide leaves of a hybri (left) variegated leaves on another variety (right)
new leaves on a variegated variety (left) more typical leaves of most hybrids (right)
Bougainvillea is an aggressive grower and a pretty easy plant to form into massive hedges, espaliers, free-form shrubs or 'trees' and well-manicured topiaries. Without any control this vine can grow up over thirty feet climbing up nearby foliage or buildings using its waxy thorns as climbing instruments. Unchecked it can do quite a bit of damage to structures by growing into cracks and crevices dislodging roofing tiles or other structures. When growing this one next to a building, it is best to trim it back away from the structure now and then.
left showing Bougainvillea growing over a fence; right is some growing over a wall and carefull pruned into a living wall
'free form' growing of vine on left and more structured training of vines in artistic sculpture (Getty Museum, Los Angeles)
left shows carefully pruned vines shaped to look like a tree (but with multiple trunks); Center and right show small scale espaliers in Los Angeles
left is a massive vine growing over forty feet tall on a Cedar deodora; right is a shorter shrub taking over preexisting foliage
This thicket-forming behavior also makes bougainvillea hedges a great place to house all sorts of unwanted pets from rats and mice to pigeons and starlings. The thorns make chasing predators into a bromeliad thicket a risky exercise. The thorns of most species and hybrids are hooked so that they usually grab hold of moving objects either on the way in or out of the vines. These thorns come in handy when growing bougainvillea as a fence hedge, allowing the vines to hook themselves onto chainlink, brick, iron etc. One rarely has to do much tying up of vines to secure this genus. The hooks also are effective deterrents if one is growing this plant as a security hedge. Few unwanted guests will hazard a climb through a dense hedge of this vicious vine. Unfortunately these spines make trimming and hauling away cut branches a bit of a task, and I have the wounds to prove it.
spines on young plant (before they become hook-shaped) left and center photos; somewhat more hooked mature spines right photo
Building on left has very old bougainvillea vines growing on and INTO building, requiring eventual removal. Dozens of creatures were discovered to be living in these dense shrubs. Left is plant getting out of control in my yard and starting to lift away the trellis behind it
This plant needs a lot of light and does not do well in shaded gardens (this is also why it doesn't do well indoors). Heat is also essential, though it seems to be able to handle, and even excel in climates with extreme heat as long as it gets watered well in them. It is a very drought tolerant genus and is ideal for growing in climates with long dry seasons as long as it gets water occasionally (eg, Mediterranean climates). In pots, this plant is a bit more touchy and will dry out beyond the point of no return if one is not diligent about watering in dry, hot seasons. When putting in pots, be sure there is not too much, if any, peat in the soil or rewetting the soil should it dry out can become an undertaking (peat soils shrink away from sides of the pot so water will just pass down and out the hole leaving the center soil dry and roots very thirsty).
literally an acre of potted Bougainvillea in a botanical gardens in Thailand (Nong Nooch)
Fertilization should be often, though I hardly ever fertilize any of my Bougainvillea and there never seems to be a lack of flowering or growing. Perhaps this fertilization suggestions pertains more to potted plants, or plants grown in very sterile depleted soils. Fertilizers should be a bit heavier on the potassium and phosphorous than the nitrogen or one may just get a rapidly growing vine with sparse flowering.
Root sensitivity can be a problem so as little damage or fiddling with roots when repotting or planting the better (root pruning is NOT recommened). Most of the roots are fine, delicate structures, but the rootball attachment to the stem is also somewhat tenuously delicate and careless planting can tear much of this connection sending the plant into a serious shock or even killing it. Because of the root sensitivity issue, it is recommended to only repot bougainvilleas when they really need to be repotted, which is when the roots are so root-bound that there is very little soil left in the pot. This plant, for me, is somewhat like a palm in that it actually seems to like being rootbound, growing best when the root are really crammed into a pot. Do not overpot this one, or you may risk root rot. However, as long as the soil is very well draining, this is not a huge worry. It is not recommended on use a water basin under potted bougainvilleas for this reason.
Bougainvilla bonsais. Don't let these roots dry out too long! photo upper left DaleTheGardener
Salt tolerance of this species is good, so it is a great vine for growing near the beach. Anyone who has driven most of the island of Kauai might recall the massive bromeliad colonies growing wild on the beaches on the drier side of the island.
Bugs are not a huge problem with Bougainvillea (snails seem to mostly ignore this plant), but grasshoppers and inchworms munch my plants up pretty severely, particurlary in shadier parts of the plant
Below are some of the more common hybrids in cultivation. This is anything but an all-inclusive list, but it gives the reader some idea of the variety of colors and what is available
Bougainvillea 'After Glow' (left photo htop) Bougainvillea 'Alexandra' (center photo kniphofia) Bougainvillea 'Bambino Baby Allison' (right photo Kell)
Bougainvillea 'Bambino Baby Lauren' (left photo Kell) Bougainvillea 'Bambino Baby Victoria (center photo Kell) Bougainvillea 'Bambino Majik' (right photo brical1)
Bougainvillea 'California Gold' (left photo Kell) Bougainvillea 'Cherry Blossom' (center photo Kell) Bougainvillea 'Coconut Ice' (right photo htop)
Bougainvillea 'Gold Rush' (left photo Kell) Bougainvilea 'Imperial Delight' (center photo Cambrium) Bougainvillea "Jamaica White' (right photo Kell)
Bougainvillea 'Key West White' (left photo artcons); Bougainvillea 'Ms Alice' (center photo IslandJim); Bougainvillea 'Orange King' (right photo Xenomorf)
Bougainvillea 'Orange Ice' (left and center) Bougainvillea 'Pink Pearl' (right photo Kell)
Bougainvillea 'Purple Robe' left (all photos Kell) Bougainvillea 'Raspberry Ice' Bougainvillea 'Rosea'
Bougainvillea 'Rosenka' (left photo Kell) Bougainvillea 'Silhouette' (center photo brical1) Bougainvillea 'Thai Delight' (photo Kell)
Bougainvillea 'Torch Glo' is a miniature species, reluctant to vine, in which the carpals and flowers form in clusters along the branches (right photo KactusKathi)
Bougainvillea 'White Madonna' (photo by Kell)
For more on growing bromeliads and information about available hybrids, see http://www.bgi-usa.com/
Bougainvillea in Southern Cal nursery