Hibiscus Synchronism

This month has seen the Crocosmia come and go, the Agastache kick into overdrive, and the beginning of the Hibiscus blooms. The Hibiscus blossums are huge--over 20 cm (8") in diameter. Over the past two weeks they've grown more numerous but somewhat smaller.

Interestingly, there are three plants--one in full sun, one in partial shade, and one of a different variety. None-the-less, all three opened their first blooms within 24 hours of each other on July 24-25.

At first one would think photoperiod or other external driver, but a neighbor about a half mile away had his (in full sun) open a couple weeks ago. I'm thinking that these three plants are sharing signals, possibly airborne but more likely subterranean. The moist mulch of this garden has had its share of mushrooms and other fungi this season, including a slime mold. I am suspicious of mycchorizal interconnections and the inter-plant transmission of a blooming trigger.

Below you can see the odd man out, the different variety with its more rugous petals and purplish leaves. Compare with the bright green leaves in the background. This is almost certainly due to more anthocyanins adding a purple tint to the leaves and even a bit to the flowers themselves.