I don’t know about you, but when it’s cold out, I tend to pull in on myself—shoulders go up, chin comes down—it’s as if I’m trying to make myself smaller in order to stay warmer. I thought of that recently as I’ve been observing the fascinating foliage on the P.J.M. rhododendron near my front door.
As the season changes, the rhododendron has been telling me how cold it is outside each morning. On chilly days — say in the teens or 20s — the leaves of the rhododendron are turned down and rolled in, sort of like a tube. If the weather is warmer—high 30s or 40s—the foliage is in its usual flat shape.
It was 18 degrees the morning I took this picture.
Rhododendrons are broad-leaf evergreens. Unlike deciduous shrubs, they do not lose their leaves over the winter. The buds for next year’s flowers and the rhododendron leaves hold on through most of the winter. According to the University of Minnesota, the curling action is a way to hold onto water during the dry, cold parts of the year. Sometimes curling is caused by disease, but that often happens during the growing season and this rhodie looked fine all summer long.
Rhododendron at 25 degrees
We’ve had a wet fall and this is a long-established shrub, so I don’t think it is struggling for water either. It’s perhaps just upset about the suddenly cold weather we’ve had! Are the leaves on your rhododendrons curling too?
Rhododendron at 40 degrees
Beth @ PlantPostings says
November 21, 2017 at 5:30 pmOh, that’s fun! I don’t have any Rhododendrons. My mom had one that she moved several times as we moved from Indiana to Wisconsin and to several houses during our growing-up years. It survived all the moves and continued to thrive. Not many of our neighbors in Wisconsin had them, but it seems the cold-hardy varieties are more common in the Midwest now. I didn’t realize the leaves curl up that much in the cold. Poor plant–the sudden cold, and then fluctuating temperatures have been shocking for plants and people, alike!
bittenbyknittin says
November 22, 2017 at 11:03 amNot so much curling as BLOOMING. There are usually a few autumn blossoms, but with the extended warm temps this year, there were more than usual. The PJM’s are right outside my bedroom window, so in winter I check their curl to see how cold it is outside.
Mary Schier says
November 24, 2017 at 10:26 amI had blooms last fall when the weather was unusually warm for Minnesota. No blooms this year, just a lot of curling!