BCSS - Forum

I only have a few doubles in my collection, but those doubles that I have often flower at exactly the same time, even if the flowers last for just 1-2 days.

It's obviously advantageous for pollination reasons that flowers of the same species open at the same time, but my question is how do they know when to do it so precisely? What's the biological mechanism?

It's uncanny, there are 365 days in the year, yet two completely separate plants flower on exactly the same day, almost to the minute.

Lucky you! I have been trying my hand at cross-pollinating some Haworthias this year but the first flowers on one spike usually open just as the last flowers on another finish.

I've noticed that happening too.

For example, I have two Echinopsis subdenudatus which look noticeably different, yet a few weeks ago both flowered on the same day, for one day - but a different day, and quite a lot later than any of the other Echinopsis nearby. I've got 2 Rebutias tarvitaensis (again, different clones) both flowering today, at least a month later than most of my other Rebutias.

In China, there are the famous bamboos which flower once every 17 years, but of course all in the same year, to avoid insects (cicadas?), but that's on a very different timescale.

I thought I'd add a picture - 3 x Copiapoa laui, all acquired from different sources, all flowering the same day (sorry I took the pic a day too late)
Maybe they secrete mating pheromones like insects do?

It varies a lot with species. I like to keep doubles of most plants I have to obtain seed, but while some will synchronize perfectly, others will not. My Astrophytum, for instance, are notable for this. Apart from A. asterias, all the others will rarely bloom at the same time, and because temperatures here in Portugal are very high the flowers rarely last more than a day or two.
One species that is amazing for its synchronicity is Turbinicarpus vierecki subsp. neglectus L1159. Because it is self-fertile I have several plants of different generations, from deliberate and volunteer sowings (apart from the original plant I bought). They all bloom simultaneously, even in different greenhouses!

I have Peniocereus greggii in bud at the moment, which is well known for its synchronous flowering in habitat. Interestingly the buds on the same plant synchronise with one another so on my plant the two most well developed buds are just hanging, looking like they will open any minute, whilst a smaller bud has suddenly shot up and looks to be catching up. I am pretty sure they will all open on the same night


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My two pelecyphora strobiliformis seem to alternate, just as a flower or two fade on one, the others buds open. Just as THOSE fade, the other opens some more. Swear they do it to me on purpose....