Bougainvillea is a vibrant, blooming vine that climbs on trellises at seaside resorts and desert retreats from San Diego to Miami. If you need a tough, tropical with oceans of color that can stand up to heat and drought, bougainvillea’s your plant.
I. Appearance and Characteristics
Bougainvillea is a genus of thorny ornamental vines, bushes, and trees belonging to the four o’ clock family, Nyctaginaceae. They are native to Brazil, Peru, and Argentina. There are between 4 and 22 species in the genus. The inflorescence consists of large colourful sepal-like bracts which surround three simple waxy flowers, gaining popularity for the plant as an ornamental. The plant is named after explorer Louis Antoine de Bougainville (1729-1811), after it was documented on one of his expeditions.
The species grow 1 to 12 metres (3 to 39 ft) tall, scrambling over other plants with their spiky thorns. They are evergreen where rainfall occurs all year, or deciduous if there is a dry season. The leaves are alternate, simple ovate-acuminate, 4–13 cm long and 2–6 cm broad. The actual flower of the plant is small and generally white, but each cluster of three flowers is surrounded by three or six bracts with the bright colours associated with the plant, including pink, magenta, purple, red, orange, white, or yellow. Bougainvillea glabra is sometimes called “paper flower” because its bracts are thin and papery. The fruit is a narrow five-lobed achene.
The first European to describe these plants was Philibert Commerçon, a botanist accompanying French Navy admiral Louis Antoine de Bougainville during his voyage of circumnavigation of the Earth, and first published by Antoine Laurent de Jussieu in 1789. It is possible that the first European to observe these plants was Jeanne Baret, Commerçon’s lover and assistant, who was an expert in botany. Because she was not allowed on the ship as a woman, she disguised herself as a man in order to make the journey (and thus became the first woman to circumnavigate the globe).
Twenty years after Commerçon’s description, it was first published as ‘Buginvillæa’ in Genera Plantarum by A. L. de Jussieu in 1789. The genus was subsequently spelled in several ways until it was finally established as “Bougainvillea” in the Index Kewensis in the 1930s. Originally, B. spectabilis and B. glabra were undifferentiated until the mid-1980s when botanists classified them as distinct species. In the early 19th century, these two species were the first to be introduced into Europe, and soon nurseries in France and Britain sold these varieties in Australia and throughout their former colonies.
Meanwhile, Kew Gardens distributed plants it had propagated to British colonies throughout the world. Soon thereafter, a crimson specimen in Cartagena, Colombia was added to the genus descriptions. Originally thought to be a distinct species, it was named B. buttiana in honour of the European who first encountered it. However, later studies classified it as 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 produced almost spontaneously in East Africa, India, the Canary Islands, Australia, North America, and the Philippines.
II. How to Grow and Care
Sunlight
Bougainvillea requires full sun, which is considered six or more hours of direct sunlight per day. It will not bloom in part shade or shade.
Watering
These plants don’t like to stay soggy. If yours is planted in the ground, make sure it’s a well-draining area. They need to be watered deeply and frequently when first planted, but, once established, bougainvillea plants are drought-tolerant.
Fertilizing
Feed your plant with a balanced slow-release fertilizer. Avoid those that are high in nitrogen, which is the first number in the NPK information on the product, says Harrison. Liquid, water-soluble fertilizer also can be used, but not at every watering.
Some fertilizers are labeled specifically for bougainvillea, which is a good idea if you want to ensure you’re using the ideal ratio of nutrients.
Planting Instructions
- Prepare the planting site by loosening the soil to a depth of about 12-18 inches (30-45 cm) and mixing in organic matter, such as compost, to improve soil drainage and fertility.
- Dig a hole slightly larger than the root ball of the bougainvillea plant. The hole should be deep enough so that the top of the root ball sits level with or slightly above the surrounding soil.
- Carefully remove the bougainvillea from its container, taking care not to damage the roots. If the plant is root-bound, gently loosen the roots before planting.
- Place the root ball into the hole, making sure it is positioned at the correct depth. Backfill the hole with the excavated soil, gently firming it around the root ball to eliminate air pockets.
- Water the plant thoroughly to settle the soil and help establish the roots. Add a layer of mulch around the base of the plant to help conserve moisture and suppress weeds.
- If growing bougainvillea as a vine, gently tie the plant to the support structure using soft plant ties or strips of fabric, allowing the plant to grow upwards.
Once established, bougainvillea is relatively low-maintenance and will reward you with vibrant, colorful blooms.
Pruning
Prune bougainvillea plants to maintain their shape, encourage branching, and stimulate more blooms. The best time to prune is after the main blooming season, typically in late winter or early spring. Remove dead or damaged branches and trim back the tips of the plant to encourage new growth. If necessary, more aggressive pruning can be done to keep the plant within the desired size and shape.
Training
If you are growing bougainvillea as a vine, train the plant to climb its support structure by gently tying the stems to the trellis, fence, or wall using soft plant ties or strips of fabric. Encourage the plant to grow in the desired direction by positioning the ties and adjusting them as the plant grows.
Overwintering
Bougainvillea is not frost-tolerant and needs protection from freezing temperatures. If you live in a region with cold winters, grow the plant in a container and bring it indoors during the winter months, placing it in a bright, sunny spot with temperatures above 60°F (15°C). Alternatively, protect the plant outdoors by covering it with frost cloth or a similar material during frosty nights.
Propagation
Bougainvillea can be propagated through several methods, but stem cuttings are the most common and successful way to propagate this plant. Here’s a step-by-step guide to propagating bougainvillea from stem cuttings:
- Choose the right time: The best time to take cuttings is in late spring or early summer when the plant is actively growing.
- Select healthy stems: Choose healthy, semi-mature stems for cuttings. These should be neither too young and green nor too old and woody. Look for stems that are about the thickness of a pencil and have at least 4-6 leaves.
- Prepare the cutting: Use a sharp, clean pair of pruning shears to cut a 4-6 inch (10-15 cm) long piece from the selected stem. Make the cut just below a leaf node (the point where a leaf is attached to the stem). Remove the leaves from the lower half of the cutting, leaving 2-3 leaves on the upper half.
- Rooting hormone (optional): Although not absolutely necessary, dipping the cut end of the stem in a rooting hormone powder can increase the chances of successful rooting. Tap off any excess powder before proceeding.
- Plant the cutting: Fill a small pot or container with a well-draining, sterile potting mix or a mix of perlite and peat moss. Make a hole in the center of the mix, insert the cut end of the cutting into the hole, and firm the mix around the stem to provide support. Ensure that at least one leaf node is below the soil level, as this is where the roots will form.
- Maintain moisture: Water the potting mix gently to settle it around the cutting and keep it consistently moist but not soggy. Overwatering can lead to rotting.
- Create humidity: To maintain humidity around the cutting, cover the pot with a clear plastic bag or a plastic dome. Make sure the plastic doesn’t touch the leaves, as this can cause them to rot. You can use stakes or a frame to support the plastic if necessary.
- Provide warmth and light: Place the pot in a warm location with bright, indirect light. The ideal temperature for rooting bougainvillea cuttings is between 70-80°F (21-27°C). Avoid direct sunlight, which can cause the cutting to dry out or overheat.
- Monitor progress: Check the cutting regularly for moisture and root development. It usually takes 4-6 weeks for roots to form. You can gently tug on the cutting to see if there’s resistance, which indicates root growth.
- Transplant: Once the cutting has developed a healthy root system, carefully transplant it into a larger pot with well-draining soil. Gradually acclimate the new plant to direct sunlight and outdoor conditions before planting it in its final location.
By following these steps, you can successfully propagate bougainvillea plants and enjoy their vibrant colors in your garden or landscape.
Pests and Diseases
Bougainvillea plants can be affected by several pests and diseases. Here are some common issues to watch for:
- Aphids
These small, pear-shaped insects feed on plant sap, causing distorted leaves and reduced vigor. They also secrete a sticky substance called honeydew, which can lead to sooty mold growth. To control aphids, spray the plant with water to dislodge the insects or treat with insecticidal soap or neem oil.
Mealybugs
Mealybugs are small, white, cottony insects that also feed on plant sap. Like aphids, they excrete honeydew and can cause sooty mold. Control mealybugs by dabbing them with a cotton swab dipped in rubbing alcohol or applying insecticidal soap or neem oil.
- Spider mites
These tiny, spider-like pests feed on plant sap, causing stippling or yellowing of leaves, and can lead to leaf drop. They often create fine webs on the undersides of leaves. Control spider mites by spraying the plant with water to dislodge them, or use insecticidal soap or neem oil.
- Caterpillars
Some caterpillar species may feed on bougainvillea leaves, leading to defoliation. Handpick caterpillars from the plant or use a biological control such as Bacillus thuringiensis (Bt).
- Root rot
Overwatering or poorly draining soils can lead to root rot, a fungal disease that causes the roots to decay. Symptoms include yellowing leaves, wilting, and an overall decline in plant health. To prevent root rot, plant bougainvillea in well-draining soil and avoid overwatering.
- Leaf spot
Fungal or bacterial leaf spot diseases can cause irregular brown or black spots on leaves, sometimes surrounded by a yellow halo. To manage leaf spot diseases, remove and discard affected leaves, improve air circulation around the plant, and avoid overhead watering.
- Sooty mold
This black, powdery fungus grows on the honeydew secreted by sap-sucking pests like aphids and mealybugs. Although it doesn’t directly harm the plant, it can reduce photosynthesis and overall plant health. Control sooty mold by managing the pests that produce honeydew and gently cleaning affected leaves with a damp cloth or soapy water.
- Powdery mildew
This fungal disease appears as a white, powdery coating on leaves and can cause leaf distortion or premature leaf drop. To prevent powdery mildew, ensure proper air circulation around the plant, avoid overhead watering, and apply a fungicide labeled for powdery mildew control if necessary.
Regularly inspect your bougainvillea plants for signs of pests or diseases and address issues promptly to maintain plant health and vigor. Proper cultural practices, such as appropriate watering, pruning, and sanitation, can also help prevent many problems.
III. Main Types of Bougainvillea
There are numerous bougainvillea cultivars and hybrids, but three main species are commonly used in horticulture. These species have distinctive characteristics and are the basis for many popular cultivars:
- Bougainvillea spectabilis
This species is native to Brazil and is the largest and most vigorous of the three main types. It features large, rounded bracts and broad, ovate leaves. The bracts of B. spectabilis come in various colors, including magenta, pink, and purple. This species is often used for breeding new cultivars due to its vigorous growth and vibrant colors.
- Bougainvillea glabra
Also known as “paper flower,” B. glabra is native to Brazil as well. It is a smaller and less vigorous species compared to B. spectabilis, making it more suitable for smaller gardens or container growing. The bracts of B. glabra are generally smaller, more slender, and smoother than those of B. spectabilis, and they come in colors such as magenta, purple, and white. The leaves of this species are relatively small, elliptical, and have a glossy surface.
- Bougainvillea peruviana
Native to Peru, B. peruviana is a more compact species with a slower growth rate. Its bracts are smaller and more tubular, and the colors range from orange to red and purple. B. peruviana has small, elliptical leaves with a slightly rough texture.
IV. Uses and Benefits
Bougainvillea are popular ornamental plants in most areas with warm climates, including Florida, South Carolina, South India, California, across the Mediterranean Basin.
Although it is frost-sensitive and hardy in USDA Hardiness 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 it ideal for warm climates year-round. Its high salt tolerance makes it a natural choice for colour in coastal regions. It can be pruned into a standard, but is also grown along fence lines, on walls, in containers and hanging baskets, and as a hedge or an accent plant. Its long arching thorny branches bear heart-shaped leaves and masses of papery bracts in white, pink, orange, purple, and burgundy.