I had that happen to a Poinsettia before...it was red when I purchased it and when it rebloomed the following year it was White!! From the research I did I found out that sometimes because they breed these in so many colors the gene pool gets mixed and sometimes they carry more than one color in the plant and can change colors? It way beyond my comprehension,lol... I have a bougainvillae that I'm trying to grow as a Bonsai...Here's a picture of it last January when it was blooming...

Vedia Eidelman - Bouganvillea is tropical, and is hardy in zones 10 and 11. It can be grown in zone 9 if in a protected location. You can grow it in a pot, outdoors, but if you have a greenhouse where it can have a longer period of warmth, it would provide you with more growth. Obviously you would need to heat the greenhouse, or at the least, bring the container inside when temps start getting in the 30's. Growing it outside, and leaving it, in your zone, will simply be treating it as an annual. It will not survive.

@User Thank you for sharing the photo of Dr. Huey Blooms. That is very helpful. That is similar to the way the blooms grew on the vine, but they look different, and I will find the photos I have of a sample of each, side by side. The bouganvillea, the rose, and just so I don't have people here making assumptions that I am WISHING this to be when in fact I never once thought about it happening, nor did I want it to happen or tried to make it happen, I have a plant that looks different from the two plants, the leaves are different, the flowers are different, the thorns and pattern of thorn growth is different. Whatever it is, it was very cool to find in my garden. @roseseek" Please feel free to have a botanist inspect your plants. Perhaps they can convince you in person of your mistaken conclusion you refuse to believe in print? I'm honestly surprised that you haven't provided any photographic evidence of your discovery. " I refuse to believe in print...are you saying you have said anything that would prove I am wrong? The only print that has been kind and helpful here is Paul's for explaining what DR Huey is and gave a photo so I could see what that looks like. I have to find the images. The last photos I took of the three together was in 2014. I will post as soon as I find them. I hope you can refrain from your comments and assumptions about how ridiculous I am. I was searching for info on a rose Bouganvillea hybrid online when I came upon this thread. And no. I haven't seen it or read anyone attempting it. Because why would they? It's impossible. You don't have to repeat, I heard you , I heard you. And I had no idea it is impossible. If you didn't pick it up from my messages here, I am no expert. haha. I know, it is obvious, and I never claimed to know more than any poster on this thread. I don't know much about these plants. I lucked out that they liked where they were planted and it gave them what they needed to stay alive through freezing winters and 100 degree temperatures in summers for years. I have had many roses and bouganvillea die in my care. I just found a sweet spot for the two that allowed them to live close to 20 years now. @User, thank you for the explanations. I learned something from your post and your link of the flowers. I really appreciate the information. When you see my photos, you can at least understand why I believed it was a hybrid. It isn't some flight of fancy. It is just comparing traits of what appeared to be three different plants with three different blooms, leaves, thorns, and the base of the plant was different, too. I didn't know about the DR Huey thing, but it is very interesting. If what I have is a take over by a rose bush that is Dr Huey created, so be it. Awesome! Mystery solved. That would make sense. I really want you to see the photos I have. At least you will see why I have been believing what I have. I have shown them to many people, and I guess they all had no idea it is impossible, too. I live in Austin now, the plants are in Houston. The plant is still very alive. It SEEMS to be more tolerant of extreme temperatures because the other two would be affected by the extremes, the bouganvillea in freezing weather and the rose in the summer heat. But this other plant that is not a hybrid, is tolerant to both extremes. Maybe the Dr Huey, when it loses its red roses, becomes more tolerant, along with other changes. I will definitely look it up. The rose bush has two blooms right now. Two big red roses. Surprising, it barely survived the winter this year, but it did! The bouganvillea, well it looks (from photos) like it didn't survive this years freeze. But it may have. We almost pulled up the trunk after pruning it down to a trunk years ago after a big freeze. We thought it was definitely dead. I am glad we didn't because It surprisingly came back, pretty as ever. (Please don't say that's impossible, too.)

@Louisa More questions to add to what I asked already: 4) Where do you live and what is your plant zone? 5) Describe your weather pattern throughout the year. 6) Applying some common sense, does the soil in which these plants live feel dry or moist between waterings, going down about 10 inches? You want to have someone do the percolation test and I gave you a link to a thread that talks about how to do it. This is very very important for your case. We have no idea if your soil is wet or dry, and whether it drains fast or slow. Bougainvillea wants to live in dry soil and then be drenched once every week or two. They want the water to drain fast. You probably don't have those conditions. Also, if you did not figure it out by now, the photo of your variant makes clear that it is the wrong plant for that small wall location unless you are willing to maybe put up a trellis and very actively prune it.