Bougainvilleas are quintessential California plants. Growing up in San Carlos, they were prolific and when we moved into our own home and started fixing it up, we added these familiar plants. They have always grown well here and hummingbirds, honey bees, and other beneficial insects like them. Flowering plants are important in any garden precisely because they do attract many creatures that aid in the health of the garden.
We have the ideal conditions, southern facing, and at the back of our house is a trellis that runs the length of our house. We planted two Bougainvilleas in large copper containers, large enough that the plants would never be root bound, and they did well, until this year.
We had a gorgeous show of flowers in the spring but throughout the summer the flowers died off and there was very little vine growth. It didn’t make sense to me, and I checked pH and looked for pests and fungus, but nothing was obviously wrong.
As you can see from the image, the plants just look weak. The leaves are pale green, there is very little new growth, and whatever growth is there is undersized and lacking vigor.
I did miss the most obvious factor and it was only recently that I figured it out. I have been over-watering these plants. As soon as I cut back the amount of water the plants were receiving, just this side of the soil drying out, new flowers emerged and shoots of new growth followed.
A little research on the care of Bougainvilleas revealed the following guidelines:
- Sun: They need at least 5 hours of sun each day, southern exposure is optimal.
- Water: Moist but not wet, the soil should be rich but drain well. Holding back water will stimulate flower growth, water frequently and new growth shoots will overtake flowers, and water excessively will cause the plant to shut down (this is what was happening to me).
- Fertilizer: At least once a year, but more frequently is acceptable. A 1:1:1 or 2:1:2 fertilizer will work best, slow release is preferred, and avoid high nitrogen fertilizers.
- Pruning: At the end of the growing season, prune back the vines a few inches to promote vigorous growth in the spring.
- Hardiness: Zone 9 or better is best and if your area has extended periods of cold nighttime weather, plant in pots and bring indoors for the winter. In my area, we get the occasional cold snap and when that is expected I will cover the plants with a sheet to protect them from frost.