If there's one plant that loves our summer, it's the bougainvillea. The hotter it gets, the better they get, or so it seems. Actually, bougainvillea blooms best on days short on daylight. But that's not really what this week's email tip is all about. Instead, it's about making the bougainvillea (Or "the bogey," as we'll call it from here on out) bloom better.
The question I get consistently on the radio program is "my bogey is growing well, and is healthy and green, but what can I do to make it bloom better?" The answer is ... and you lazy gardeners are truly going to love this ... to torture it! Make it suffer!!
First, when we talk about bogey's "bloom," it's sort of a misnomer. The beautiful pink/red/orange color isn't a bloom at all ... it's a modified bract, sort of like a poinsettia's. The actual bloom, once you get the modified bracts, is the tiny little tube with an inconspicuous white/yellow flower on the end.
But to make a bogey "bloom" better (for the sake of this discussion), we need to apply some stress. And we can do that in a couple ways. If the bogey is in a container, it should be deprived of water to the point at which it wilts pathetically. Once you have mercifully decided it has wilted enough, you can water it and keep it well watered from that point on. The stress, along with some appropriate food (which I'll get to in a moment) and some selective pinching-back of longer branches, forces the modification of the bracts.
If the bogey is in the ground, and you can't deprive it of moisture either because of an automatic sprinkler or because of Mother Nature, then you must abuse the bogey by selectively severing the roots. That means getting a sharp shooter-type (sharp blade) shovel and making cuts into the root system about two feet away from the trunk. You make a cut, skip over a shovel length and make another cut. Sort of cut, space, cut, space, cut, space, etc. Here too, you want to do some slight pinching-back of branches here and there to hasten the bract changes.
In both cases, it's essential to feed the bogeys at least once a month with something like a hibiscus food. Hibiscus foods are normally higher in nitrogen and potassium than they are in phosphorous (the middle number), and that's what we want, because we aren't trying to make it "bloom" the way we do with flowers.
Containerized plants actually like water-soluble plant food better, and there are not a lot of water-soluble hibiscus foods, other than Carl Pool's Hibiscus Food and the plant food of the Space City Chapter of the Hibiscus Society that's sold exclusively in the Houston area. However, you can use simple 1-1-1 water-soluble plant foods for containerized bogeys with confidence.
The more commonly found granular hibiscus foods are safe to use on all in-ground bogeys. There is one very specific bogey food on the market ... Nelson's Nutri Star for Bougainvillea, from the makers of Color Star, It too can be used on containerized bogeys. The beauty of Nelson's Nutri Star is that you only have to use it once every two months - all the other foods mentioned above need to be used on a monthly basis for optimum results.