Opuntia Bloom Question

[Harriet]

I have two established Opuntia humifusa plants. One from Missouri, one from Florida. Both have 35+buds on them, the Florida one has started blooming, the other is probably a week behind. The only difference is the amount of direct sunlight they get, otherwise soil, temperature, water are all about the same. Is the difference in bloom time a factor of the light, or is plant genetics in play here? Would the variety grown in the colder north be genetically predisposed to a later bloom than the same variety accustomed to warmer weather and earlier springs?

[RayC]

Interesting question and I don't know the answer. Is your 'cold' one the one that gets more light or vice versa?
I do know mine, only native cactus here (which I believe is from Connecticut source) is about the first to show ouward signs of going dormant in the fall, and also a little slower then some other varietes to get started in the spring.

[Andy_CT]

Differences in amount of direct sunlight can certainly make a difference in how quickly plants are pushed along. I've seen a garden in Massachusetts that gets sun literally all day long and that garden is easily 2-3 weeks quicker than mine which gets only 4-5 hours of direct sun.

[Harriet]

It only seems logical that the amount of light would make a difference. I was mostly interested in whether or not the plant's origin/gene pool would be a factor.

An interesting aside to all of this is that the second plant started to bloom today, and the flower size is easily 20-30 percent smaller than the plant in the sun.

[Peterthecactusguy]

I would assume temperature plays a factor too. With mine, my O. engelmannii native to AZ had buds in JAN this year due to warm temps. The O. humifusa has finally woken up but still hasn't really put any buds on yet. No idea if I am even getting flowers with it this year. FYI in my area of BCC most of the rest of the Opuntia are blooming but mine!

[Harriet]

I suppose it could, but I doubt that temperature plays much of a part in this case, since there is probably only 50 feet separating the two.

[iann]

The more northerly plant might actually flower earlier, depending on what triggers it into flower.

[Harriet]

I should try an experiment and put them both next to each other to see if they bloom at the same time next spring.

Or not, there would be work involved and I'm pretty lazy...

[martenfisher]

I collect specimens by bloom time from different areas. If I go to one part of withlacoochee and they bloom they may bloom different in another part maybe even a month or so. I collected a dillennii that blooms all year non stop. I think genetics is 90 percent then after that the natural processess of cold and daylight.