There are some other examples like that in biology, my favourite being 13- and 17-year periodic cicadas [1] with one theory being that a prime number was selected for during evolution to make it more difficult to synchronize with predator life cycles.

Counters in biology are also a thing, for example Hayflick limit [2] which is a number of times a single cell can divide before it dies (partially explained by telomere shortening due to particularities of replication of the lagging DNA strand 3). What is interesting here is that plants from the same clone grown in different climates likely grow at different rates so the counter must be decoupled from cell division. Perhaps accumulation of some metabolite that adds up every season triggers it at some threshold?

[1] https://en.wikipedia.org/wiki/Periodical_cicadas [2] https://en.wikipedia.org/wiki/Hayflick_limit [3] https://en.wikipedia.org/wiki/Telomere#Shortening