Bougainvillea 101
bou·gain·vil·le·a [boo-guhn-vil-yuh; -vil-ee-uh; boh-]
Introduction
The Bougainvillea is an immensely showy, floriferous and hardy plant. Virtually pest-free and disease resistant, it rewards its owner with an abundance of color and vitality when it is well looked after. The bougainvillea's versatility is legendary. It can be coaxed into a small manageable pot plant or a sizeable tree, to spread itself vertically on a wall, or climb up a trellis and form a luscious crown or burst forth into graceful arches. It makes one of the best hedges, bushes, and curb-liners. And as for bonsai or topiary purposes, it has few equals, lending its complex branching to the pruning shears, which promote even more unique and graceful forms. It is probably true to say that without the bougainvillea, our roads, parks, and private gardens would be a lot less colorful that what we see today. Almost everywhere we go, its brilliant hues and cheerful bursts punctuate the lush green mantle that cloaks our tropical environment. Other flowering plants certainly pale in comparison. [1]
Along with palms, sunshine, and beaches, the cascading blooms of bougainvillea provide one of Florida's signature tropical images. As a profuse bloomer, bougainvillea is most striking during the winter, when it is at its peak and few other plants are able to provide color. Although it is frost-sensitive and hardy in zones 9b and 10, bougainvillea can be used as a houseplant or hanging basket in cooler climates. In the landscape, it makes an excellent hot season plant, and its drought tolerance makes bougainvillea ideal for warm climates year-round. Native to the coasts of Brazil, bougainvillea has a high salt tolerance, which makes it a natural choice for south Florida and other coastal regions. As a woody clambering vine, bougainvillea will stand alone and can be pruned into a standard, but it is perfect along fence lines, on walls, in containers and hanging baskets, and as a hedge or an accent plant. Its long arching branches are thorny, and bear heart-shaped leaves and masses of papery bracts in white, pink, orange, purple, and burgundy. Many cultivars, including double flowered and variegated, is available. [2]
History
A native to coastal Brazil, the bougainvillea was discovered in 1768 in Rio de Janeiro by French naturalist Dr. Philibert Commerçon (also sometimes spelled Commerson). The plant is named after his close friend and ship's admiral Louis-Antoine de Bougainville, who commanded the ship La Boudeuse that sailed around the world between 1766-1769, and in which Commerçon was a passenger.
Twenty years after Commerçon's discovery, it was first published as 'Buginvillea' in Genera Plantarium by A.L. de Jusseau in 1789. The genus was subsequently split in several ways until it was finally corrected to 'Bougainvillea' in the Index Kewensis in the 1930s. Originally, B. spectabilis and B. glabra were hardly differentiated until the mid 1980s when botanists recognized them to be totally distinct species. In early 19th century, these two species were the first to be introduced into Europe, and soon, nurseries in France and England did a thriving trade providing specimens to Australia and other faraway countries. Meanwhile, Kew Gardens distributed plants it had propagated to British colonies throughout the world. Soon thereafter, an important event in the history of bougainvillea took place with the discovery of a crimson bougainvillea in Cartagena, a Spanish port in the Mediterranean, by Mrs. R.V. Butt. Originally thought to be a distinct species, it was named B. buttiana in her honour. However, it was later discovered to be a natural hybrid of a variety of B. glabra and possibly B. peruviana - a "local pink bougainvillea" from Peru. Natural hybrids were soon found to be common occurrences all over the world. For instance, around the 1930s, when the three species were grown together, many hybrid crosses were created almost spontaneously in East Africa, India, the Canary Islands, Australia, North America, and the Philippines. [1]
Scientific classification
Kingdom - Plantae Division - Magnoliophyta Class - Magnoliopsida
Order - Caryophyllales
Family - Nyctaginaceae
Genus - Bougainvillea
Species - Bougainvillea spectabilis
Bougainvillea glabra
Bougainvillea peruviana
Cultivar (or variety)
Note about Species: Many of today's bougainvillea are the result of interbreeding among only three out of the eighteen South American species recognized by botanists.
Note about Cultivars: Currently, there are over 300 varieties of bougainvillea around the world. Because many of the hybrids have been crossed over several generations, it's difficult to identify their respective origins. Natural mutations seem to occur spontaneously throughout the world; wherever large numbers of plants are being produced, bud-sports will occur. This had led to multiple names for the same cultivar (or variety) and has added to the confusion over the names of bougainvillea cultivars.
Species and Hybrids
Bougainvillea spectabilis is a large climber with distinctive curved thorns, and hair on stems and leaves. The bracts are crinkled, fairly large, egg-shaped, and possess colors in the rose, rusty-red, and purple. Flowers are cream in color, slender, with very hairy tubes. Leaves are large, ovate to rounded, leathery in texture and hairy underneath. The bark is pale and corky. Branching is close and short, giving rise to a very dense plant. The first species collected, it was described from dried specimens by Willdenow (1798).
Bougainvillea glabra has thinner branches that spread in many directions and have distinctive pointed triangle-shaped bracts that come in a range of whites, lilacs, mauves, and purples. Thorns are short, thin, and curved at the tips. Leaves are fairly evenly elliptical, widest about the middle. The small cream flowers are relatively big and tube-shaped. The also tend to flower virtually continuously, and often down the entire length of the branch. Originally described and named by Choisy (1849).
Bougainvillea peruviana has a branching habit that is looser and more open. This is a climbing, spiny, spreading shrub with greenish bark. Thorns (spines) are thin, straight in youth and curved when older. Leaves are thin and ovate to broadly ovate. The small roundish bracts, usually in light to dark magenta colors, are quite delicate to the touch, and are crinkly in appearance. Flowering is recurrent after strong vegetative growth in response to dry weather. This species was described and named by Humbold and Bonpland (1808).
Bougainvillea hybrids found today have been grouped into these three hybrid groups:
- B. x buttiana (glabra x peruviana)
- B. x spectoperuviana (spectabilis x peruviana)
- B. x spectoglabra (spectabilis x glabra)
Best Climate for Bougainvillea
Bougainvillea are tropical and must be protected from frost. In Zone 8 and cooler, you are almost limited to growing them in some kind of container unless you treat them as an Annual (plant a new plant outdoors each year) -- which works fine if you obtain a large plant in the spring. Bougainvillea thrives in full sun. At least 5 hours a day of full sunlight is the minimal light required for good bloom. More hours of direct sun are better. Less than 5 hours and the plant may not bloom very well. In shade or partial shade, you will have nice vegetative growth, but little or no bloom. A Bougainvillea just doesn't bloom well indoors. If possible, keep your plant outdoors (in the maximum sun available). If placed on a porch, patio or balcony, where the plant receives at least 5 hours of sun each day (afternoon sun is best), then it should bloom ok. A bougainvillea likes high humidity just before it comes into bloom. Once bloom has been initiated, then it will tolerate less humidity. [2]
Production
Bougainvilleas' natural habitat is equatorial where day and night lengths are almost equal. Bougainvillea in these areas tend to bloom year round, but in North America, best blooming occurs when the night length and day length are almost equal (in spring or fall). In winter, blooming is better than in the dog days of August because of night length. Also, some cultivars are triggered to bloom after a rainy season followed by a dry season.
Light Levels
As a tropical plant, Bougainvillea requires full sun, or a light level of at least 4000 f.c.
Production Temperatures
Temperatures should be maintained somewhat high; a minimum of 65°F at night and 75° to 95°F during the day. Growth production will be delayed at cool temperatures, especially if the soil is also cool.
Salt Tolerance
Good salt tolerance. [3]
pH Preference
Bougainvillea does best with a soil pH of 5.5-6.5
Media
Bougainvillea has an extremely fine root system, and should be planted in well-drained soils. Avoid soil mixes with high peat levels and water retention. These types of media retain too much water and will contribute to root rot; be sure to select a well-draining media.[2] The best growing mixture is one that is soil-less. Soil-less media are free of any disease pathogens, insect pests, and weed seeds. They are also generally lightweight and porous, allowing for a well-drained yet moisture-retentive mix. Premixed growing media are available from garden centers. However, be careful not to use peat or peatlite mixes alone. By themselves, these media tend to become compacted, too lightweight, and hard to wet. The greatest problem with peat/peatlite mixes is when the soil dries completely, the root ball will pull away from the side of the pot, and it is almost impossible to completely wet the soil again -- the water simply runs down the side of the container and drains out the bottom. If your plant dries out and you use this type of mix, to rewet it, let the pot sit in a pail of water until the soil ball is completely wet. Before using your mix to repot plants, be sure it is damp. Totally dry soil mixture is difficult to handle and may damage tender roots before the plant is watered.[4]
Fertilization
Bougainvillea are heavy feeders that require regular monthly fertilization. Nitrogen and phosphate are critical to flowering, but do not overfertilize with these two elements because it will add growth and inhibit blooming. This is the case when using generalized fertilizers like a 20-20-20 or 12-12-12. That’s why we’ve created a blooming fertilizer specifically for bougainvillea called BOUGAIN®. With Bougain’s 6-8-10 plus Minors formula, Nitrogen levels are just right for flowering, but low enough to limit excessive green growth. In addition, Bougain® contains 5% Iron -- and any professional grower will tell you that’s the secret for vibrant, beautiful color on bougainvillea.
Pruning & Pinching
Bougainvillea may be pruned at any time of the year. Bloom initiation does not depend upon pruning - a bougainvillea has a bloom cycle followed by a rest period whether pruned or not. A hard prune is recommended when you need to contain growth or when you are preparing to move your bougainvillea indoors for the winter. The ‘Soft Prune’ is recommended for bougainvillea only when trying to obtain a special form. A bougainvillea, like most vining-type plants, will continue to grow outward without sending out side branches from each leaf-bud point unless the stem is pinched. If you want one long stem, then don't pinch out the tip. By pinching out the tip, most bougainvillea cultivars will send out new stems from 2 to 3 leaf-buds below the cut. Some varieties do not send out any new stems, so their appearance is always stringy or bare. BGI only produces varieties that will send out 2-3 new shoots, so you don’t have to worry about a BGI® bougainvillea ever looking stringy – that is, unless you forget to pinch! So it is important when growing a bougainvillea, not to wait for the branches to grow very far beyond your desired size before you remove all the tips -- otherwise, the growth will be bare in the center of the plant, and the overall look will be misshapen.
Growth cycles
The bougainvillea has two distinct growth cycles:
1. A vegetative growth period for several weeks -- when new leaves and stems grow. If the plant receives enough sunlight, the plant will form buds during this time. If there is not enough sunlight, the plant will remain in vegetative cycle.
2. A blooming period of several weeks when little or no vegetative growth occurs. The length of time they will display color is dependent upon the health of the plant and the environment they are in; the more sun and heat, the better. However, long days and short nights (July and August in Florida) limit a bougainvillea's ability to bloom.
Photoperiod/Flowering
Blooms occur only on new growth, so new growth on plants is vital to the achievement of flowering. Bougainvillea normally flowers during the short days of winter, but blooms are highly dependent on temperature. Drought stress can also stimulate flowering even with long daylight exposure. Growers frequently allow plants to dry just to the point of wilting to induce flowering. However, excessive drying can cause leaf drop and dormancy; use care and be sure to water at first signs of wilt. [2]
Landscape Culture
Bougainvillea is a wonderful addition to any landscape, whether it's used as a permanent fixture, a container plant or hanging basket in a semi-tropical landscape, or an annual in cooler climates. For the best performance out of your Bougainvillea, follow these guidelines: [2]
- Keep Bougainvillea on the dry side, especially if you want lots of blooms. Too much water will promote root rot and cause leaves to drop. Don't water on cool nights.
- Use a high-bloom fertilizer.
- Plant or place Bougainvillea in full sun. As a potted plant, flowers will last for up to eight weeks if kept in a sunny location.
- Winter dieback may be a problem if the weather gets too cool, so if you're growing Bougainvillea in a frost-prone area, plant in a protected location or cover in case of frost.
Frost Tolerance
Bougainvillea require winter protection. It may be killed if the temperature remains below freezing for more than 4 hours. A light frost will not kill a mature bougainvillea, but may for a young planting. Within a day after the frost, all the leaves and bracts will fall off. If they remain on the plant, they may have a “singed” or “burnt” look to the edges. In this case, the plant will regrow, but only if not subjected to further frosts for longer durations.
Winter Protection
It is not unusual for a bougainvillea to be full of bloom when it comes time to move it indoors for winter. Almost immediately after bringing a plant like this (full of bloom) inside, all the bracts will fall off and most of the leaves will eventually fall off as well.
It’s recommend that you do a hard prune before moving it indoors:
Bougainvillea is a vine and new growth (after a prune) starts one or more leafbuds below the cut and not up and down the entire branch. By doing a "hard" prune, next spring, when the plant regrows it will be fuller from the base up. Most reference to pruning bougainvillea I have found on the web is applicable more to nonvining plants where new branches grow up and down the stem after a pinch -- vines or climbing plants tend to grow only one or two branches from the leafbuds just below the cut after pruning. If you like the shape of your plant now, then you may not even want to prune before moving it indoors. Next spring it will hold the same shape, just grow larger. But, if is not quite the shape you desire or is overgrown, the best thing to do would be to perform a hard prune. [4]
Bringing Indoors for the Winter
If you have planted your bougainvillea in the soil outdoors and want to dig it up and move it indoors for the winter, expect the plant to go into dormancy sooner than if it had been in a container -- the root damage as a result of digging will be the cause rather than the cool weather -- but the plant should survive this kind of transplanting. Make sure to dig as far away from the root system as you possibly can. It’s important not to sever the roots; take care to dig up the entire root ball and especially in one piece.
Any space which doesn't freeze will be fine for your bougainvillea while indoors. If you put your plant in a high light area which remains warm during the winter nights, it may not go into dormancy and will be in better shape once Spring comes. If the spot you have doesn't have much light and stays cool during the day, then expect the plant to go into dormancy. After a few weeks indoors bougainvillea may go into dormancy and all the leaves will fall off. While indoors, water very little, and just keep the soil slightly damp.
Planting In Containers
Generally, bougainvillea can be grown in anything that will hold soil and allow proper drainage. Some of the more traditionally used containers include terra cotta (clay) pots, plastic pots, hanging baskets, wire baskets lined with sphagnum moss or fibrous liners, concrete planters, planter boxes, and bushel baskets. When BGI was on a bougainvillea exploration trip through Southeast Asia, we saw beautiful bougainvillea growing out from old laundry baskets and tires! Just remember that the container MUST have proper drainage. If you place your pot directly on the ground, the roots may emerge from drainage holes and find their way into the earth. To prevent this, place wooden slats or four bricks (in a T-design) under the pot. The air will naturally prune the roots that are exposed.
It’s very important to remember that a bougainvillea does not tolerate standing in water. Whatever container you choose, consider these tips:
- Drainage: Bougainvillea must have it.
- Insulation: Avoid using black containers in full sun.
- Large enough: The container must be large enough to hold the minimum amount of soil required for mature plants to grow in.
- Weight: Will it be too heavy to move? Styrofoam peanuts can be used in the bottom of the container rather than filling it fully with soil mix. This should also help with drainage and keeping drainage holes clear of debris.
Repotting Bougainvillea
A bougainvillea blooms best when pot-bound so do not be tempted to re-pot unless you must. It is best to leave the plant in its original container until the roots have replaced all of the soil and you can't keep the plant well watered. For example, it is not unusual to grow a bougainvillea in a 1 gallon pot for three or more years. When it is necessary to re-pot remember that a bougainvillea has a very delicate root system and a fragile root to stem connection. Handle bougainvillea with care. Root pruning is not recommended when re-potting bougainvillea - in fact, disturb the roots as little as possible because the plant might go into shock and take weeks to recover. Bougainvillea love to be pot-bound, so pot in the smallest container available for the purpose you desire. [4] Re-pot into larger pot sizes gradually. For example, move a plant in a 6" pot into a 9" or 10" pot. Several years later, you can then move up to a 14" pot. The root system needs time to grow into each new pot.
Bibliography:
[1] Simon, Eric. "Brighten Up With Bougainvillea" 2005
[2] Schoelhorn, Richard and Alavrez, Erin.
"Warm Climate Production Guidelines for Bougainvillea".
University of Florida/ IFAS Extension. October 1, 2002.
[3] Knox, Gary W. and Black, Robert J.
Salt Tolerance of Landscape Plants for South Florida. Table 5. Salt Tolerance of Vines.
University of Florida/ IFAS Extension. Reviewed March 2000
[4] Braswell, Gordon. "Gordon Braswell's Bougainvillea Information".
