Q: In the last few years, my rhododendron has bloomed out of season. This year, it bloomed fairly heavily in early October, and in the past, it has even bloomed in a warm spell in January. Why does that happen?
A: Some rhododendrons are programmed genetically to bloom lightly in the fall and more heavily in spring, said Don Smart, president of the American Rhododendron Society. Since this hasn't always been the case with your plant, though, it's more likely the rhododendron has been affected by climate conditions.
The bloom this fall was probably related to a dry summer. Very dry conditions can push a rhododendron into a near-dormant state, Smart explained. When the temperature cools in fall, the plant thinks it's spring, when it normally breaks dormancy. It responds by putting out some flowers. Similarly, a January thaw might trick the plant into thinking spring has arrived and cause it to open some blooms.
Either way, you should still have at least some flowers the following spring, Smart said.