This time of year never fails to renew the color and frequency of the blooms of bougainvillea and hibiscus. This is one time of year that our weather is similar to San Diego in the summer. We get constant questions from folks who want a bougainvillea that is “really red” like those spotted in southern California. The sad truth is that the same color in a coastal climate looks different in the desert. When you look at a few important factors, this isn’t so hard to understand.
Bougainvilleas are cyclical bloomers. As new growth tips mature, the bracts that are the colorful part of the bloom emerge and while they are new and fresh, their color is strong. In a desert climate, the hot air dries those new bracts out much more quickly, and as they age they become lighter in color and then persist on the plant for quite some time. In a cool, humid climate they stay fresh for a much longer time so that gives the impression that the flower bracts are a darker, more color saturated variety.
The best red varieties, no matter where grown are Barbara Karst, which makes up 90 percent of the red bougainvilleas seen in Tucson, San Diego Red (also known as Scarlet O’Hara), La Jolla and James Walker. The best pink is Rosenka, and there are several great pink-orange combinations such as Camarillo Fiesta and Rainbow Gold. Orange King is the brightest of the orange colors and California Gold , the best of the gold or yellow group. There are stunning purple varieties like Purple Queen and Royal Purple that hold their color exceptionally well and can be grown as a bush or a vine.
There are numerous varieties that truly are shorter and bushier for use as a shrub or in a container such as Temple Fire, Torch Glow (also known as Bangkok Red), Fireball and Firemound. This is by no means a complete list, but it covers the tried and true that outshine their competitors in Tucson landscapes.
With hibiscus, a similar cultural ease takes place.
In our hot, dry part of the summer, hibiscus blossoms tend to desiccate at the junction of the flower and stem, causing them to drop off prematurely. As we cool down and have a bit more humidity, the flowers have much more tendency to open fully and stay on the plant longer. There are so many great hibiscus varieties it would be near impossible to list the good ones, but it’s easy to say there is one to suit every person’s color choice.
Tucson is not a tropical climate, but in many parts of the valley it is almost easy to believe that. The biggest differences are the temperature fluctuations and lack of humidity most of the year. If either of these plants is being added to the landscape at this time of year, it should be soon so it can get settled in before we get close to freezing temperatures. If it is going into a container, it is much more easily protected during a freeze.
Enjoy these tropical beauties. They will soon be at their peak!