Bougainvillea plants are nicknamed flowering machines because they grow rich green foliage and bright colored flowers. The striking neon-colored blooms showcase their beauty against the green foliage background.
These plants have varying sizes, and they can grow anywhere between 3 – 40 ft. (1 – 12m) in height. Yellow leaves are the most common problem for the gorgeous Bougainvillea plants.
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What Causes Bougainvillea Leaves to Turn Yellow?
Bougainvillea plants can develop yellow leaves as a reaction to environmental stress. Inadequate water and poor lighting are the most common reasons, but you should also inspect for nutrient deficiencies and pests. Improve the plant care for your Bougainvillea to avoid yellow leaves. All the yellow leaves should be trimmed or pruned; otherwise, your plant will waste energy on reviving them.
What are Bougainvillea Plants?
There were originally 18 species of Bougainvillea plants native to tropical regions like Peru, Brazil, Southern Argentina, and South America. But today, we have almost 300 species as a result of interbreeding by botanists.
The Bougainvillea genus was described by Philibert Commerçon, a French naturalist. This genus features thorny ornamental vines, bushes, and trees. Although the heart-shaped leaves are beautiful, the most attractive feature of this plant is the vibrant blooms.
The inner flower is surrounded by 3 or 6 sepal-like bracts. These bracts vary in different shades of pink, white, orange, red, purple, or yellow.
All Bougainvillea varieties make an excellent summer plant for landscapes. They are commonly found growing on the walls, along fence lines, in containers, or hanging baskets.
These flowering plants put a lovely show of large blooms in spring and summer. Some of the famous varieties are mentioned below.
The Bougainvillea Spectabilis – this Latin plant name translates to spectacular, representing the showy blooms of this species. The blooms are rose-colored. This is the most popular species of Bougainvillea for indoor gardening. It was described by Carl Ludwig Willdenow.
San Deigo Red – this gorgeous variety has earned the Award of Garden Merit by the Royal Horticulture Society. It is great for gardening in cold climates. It produces flowers in shades of red.
Mary Palmer’s Enchantment – this variety is a multistemmed Bougainvillea. It produces stunning round white flowers from spring to fall. The leaves are also unique, with pointy tips and curved edges.
Bougainvillea Glabra – this is another common variety of Bougainvillea. It has carmine or rose-colored flowers. A mature Glabra plant reaches a maximum size of 10 ft.
Bougainvillea Variegata – as the name implies, this species is a variegated Bougainvillea. The flowers resemble the original plant, but the leaves are greyish green with creamy variegation.
Bougainvillea Lady Baring – this one is an extra-large variety. It has other names like Hawaiian Gold and Yellow Glory. It produces clusters of yellowish-orange vibrant flowers. It requires plenty of room because it can grow up to 30 ft. tall.
How to Care for a Bougainvillea Plant?
Bougainvillea plants are evergreen in most climates but behave as deciduous during dry seasons.
The growth rate of these plants depends on the variety you are cultivating. But most varieties require a dry soil mixture and very bright full sunlight (6 hours). For this reason, you will mostly find them thriving in outdoor areas.
This plant species also appreciates frequent fertilization to bloom profusely. These beautiful plants will not flourish in overwatered soil, so only water when required.
Young plants require regular watering, whereas more established ones should be watered 3-4 weeks only. Bougainvillea plants are hardy in USDA hardiness zones 9b to 11.
The sap of Bougainvillea plants is toxic and causes skin rashes. I would suggest thoroughly washing your hands after handling this plant.
Top Reasons for Yellow Leaves on Bougainvillea Plants
Treating or preventing yellow leaves on Bougainvillea depends on the reason behind the yellowing. If your outdoor or indoor Bougainvillea leaves are turning yellow, you should inspect them one by one for the following.
Water Stress
Water stress due to over or under watering is the most common cause of yellow leaves on houseplants, including Bougainvillea.
Overwatering can drain the lush green color of your Bougainvillea. Once you are sure that your plant has been overwatered, stop watering for about a week.
You can add peat moss, organic material, or compost to the soil mix to improve drainage.
Remember, these tropical plants get plenty of water through rainfall in their native region, but most other climates do not have such rainfalls. Therefore watering less can also cause yellow leaves; this is true especially for young Bougainvillea.
You can confirm this by the leaves. If they are yellowing and wilting, you have underwatered your plant.
Lack of Sunlight
If the older leaves on your Bougainvillea plant are in a shaded spot with insufficient sunlight, they will turn yellow.
As mentioned earlier, these sun-loving plants need bright full sun. You should give them at least 6 hours of full sun in a day.
Transplant Shock
If you have recently moved your outdoor Bougainvillea inside for winter, it can develop yellow leaves due to transplant stress.
One way to reduce the risk of transplant shock is by gradually moving your Bougainvillea to the new location. You can shift the plant indoors for a few days and take it back outside. Repeat this several times before moving it permanently.
You should also avoid fertilizing or overwatering your plant after transplant.
Pests
Pests like spider mites can cause yellow leaves on Bougainvillea. Look for webs and tiny moving dots on the top and bottom of the leaves.
Spray the infected plant every 2-3 weeks with forceful water jets to dislodge the spider mites. You should also treat your plant with organic horticulture or neem oil.
Cold Temperature
Bougainvilleas are tropical beauties found growing in coastal areas. They do not adjust well in colder regions.
Therefore, if you reside in a cold area, your Bougainvillea plant will struggle with temperature, especially cool winter temperatures. Bougainvillea leaves turn yellow as a reaction to cold weather.
Move your Bougainvillea plant to a warmer location and try to replicate the tropical environment for better leaf color and growth.
Nutrient Deficiency
Bougainvillea plants should be fertilized regularly to maintain the green foliage and flowers.
Yellow leaves on Bougainvillea indicate a deficiency of magnesium and iron. Fertilize it with a balanced fertilizer designed specifically for Bougainvillea or Hibiscus plants.
Or create a mix by blending 1 tablespoon of Epsom salt in 1 gallon of water. Apply this mixture to the foliage and soil to enhance the magnesium and iron content.
If your plant has twisted yellow leaves, there is zinc deficiency. You can either get a fertilizer that has zinc or add chelated zinc.
Always make sure the fertilizer or nutrients are added according to instructions on the label.
What Should I Do with the Yellow Leaves on My Bougainvillea?
The yellow leaves are not producing any food or energy for your plant since they do not play any role in photosynthesis. Instead, they might be using the energy of your plant.
It is best to discard them to save energy and enhance the look of the plant. You can prune the yellow leaves using a clean, sanitized pair of cutters or garden scissors.
Frequently Asked Questions about Bougainvillea Leaves Turning Turn Yellow
Can humidity cause yellow leaves on Bougainvillea?
Low humidity stress can cause yellow leaves, so you should aim for at least 50% air humidity for the Bougainvillea plants.
Can the yellow leaves on my Bougainvillea turn green?
The leaves that are entirely yellow cannot turn green. But those who have just started yellowing might turn green if you improve the conditions for your Bougainvillea.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.