Question
My 6 plants are potted outside in Houston,Texas. They are well drained in non-black containers. I fertilize them once every 2-3 weeks, depending on how much they need water. Some of them are blooming, and some are not, but I am more interested in why the leaves are turning yellow. My fertilizer is slow release in pellets. I really do appreciate any help you may offer. The plants get both morning and afternoon sun, and I use city water from Conroe.

Answer
Melissa,

I too raise bougainvilleas in northern IN and I love them dearly. I have learned that youu have to be very careful with the watering of bougies, they cannot stand to sit with any water in the drain tray. It must be emptied an hour after watering the plant.

The following article that I found online recently on raising bougies is excellent:

BOUGAINVILLEA INFORMATION by GORDON BRASWELL.

Gordon Braswell is a retired nursery owner who specialized in Bougainvilleas.

INTRODUCTION:  One of the beauties of bougainvilleas is the way they show off their blooms (acutally, their bracts). In this tutorial, I will strive to give useful information about growing bougainvillea so that you may enjoy this wonderful flowering vine.

Since my expertise is in growing bougainvillea in containers and not in the landscape, the information I provide is centered around growing in pots, baskets and other type containers.
Bougainvillea Bloom Season in North America
Bougainvilleas' natural habitat is equatorial where day and night lengths are almost equal. Bougainvilleas 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.

Best Climate for Bougainvillea
Bougainvilleas 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.

Bougainvilleas thrive 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 is 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 initated, then it will tolerate less humidity.

Bougainvillea has two distint growth cycles:
A vegetative growth period for seveal 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.
A blooming period of several weeks when little or no vegetative growth occurs.

The length of time they will bloom 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 ability to bloom.
Choosing a Container
The image for this page is bougainvillea in a 1-gallon nursery container. I have successfully grown bougainvillea in a 1-gal pot for 3 years or more, so don't rush to repot - the plant will bloom better when pot-bound. It is important that you don't place the pot directly on the ground -- in one summer the roots will grow down into the soil and roots will be damaged when you lift the pot -- all the feeder roots will be left in the ground. I always place a container on something other than the ground. Air will prune the roots and they won't grow out of the holes in the bottom of the pot.

Drainage is Essential
Notice the saucers on the pot and also on the hanging basket. If you use these type containers, I strongly recommend that you take the saucer off -- you will damage bougainvillea roots if the plant stands in water or the water can't drain completely from the pot.

Try all kinds of 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, whiskey barrels, 5-gallon buckets, tubs, and bushel baskets. Some of these containers are more durable than others are.

Don't limit yourself to the traditional when it comes to choosing a container. Be creative! Choosing a container that fits the look you are trying to create is half the fun of growing bougainvillea in containers!

Some self-watering containers have been manufactured to improve drainage and also have built-in reservoirs for watering plants. It is 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.
Soil suitable for Bougainvillea


I feel your main problem with the yellowing leaves is probably drainage and water sitting in the drain trays. I have had the same problem. If you have more questions after reading that write again and I will try to answer for you. Good luck.

Darlene