Foliage of the black tupelo tree, Nyssa sylvatica. We live in the northernmost part of native range of this beautiful and stately tree.
The underlying color of foliage is yellow–leaves begin yellow and turn green when they begin to produce chlorophyll. So why do some trees go to the trouble of turning fiery red in fall?
There are several theories. Some woody plants, vines in particular, turn red to signal to birds that their berries are ripe (birds have excellent color vision). Virginia creeper and poison ivy, two native vines that are particularly beneficial to wildlife, turn fiery red in fall, usually while the trees around them are still green. Ecologists call this a foliar flag.
A foliar flag: poison ivy growing up a tree trunk turns red in early fall, while the tree that supports it is still green, to signal to birds that its berries are ripe.
But maples and tupelos both flaunt bright red foliage in fall, although their fruits ripen much earlier in the season. Why do the trees waste all the energy it takes to produce red pigment? There are many theories: to protect against insect damage or sunburn at the crucial time of leaf abscission, or to fool insects into thinking the tree is dying; they’re neatly summarized in today’s NY Times. Read about it there, and be sure to get outside and enjoy the short-lived show. There are lots of lovely red and sugar maples around our area, and even a few tupelos.
I’ll leave you with a brain teaser: the foliage of which native shrub turns a deep purple/pink color in fall?
Native sugar maples are plentiful in our area; they turn beautiful shades or red and orange. Many dogwoods and viburnums turn dark red.
This is a beautiful native vine whose berries are highly attractive to wildlife. It’s lovely throughout the growing season; in autumn, it displays a foliar flag to let the birds know that its berries are ripe. More birds eat its berries than those of almost any other plant. You know that I’m describing poison ivy (Toxicodendron radicans), right?
Check out this post on the Beautiful Wildlife Garden website for more information about this very important native plant. For one thing, only humans are allergic to it. And among humans, by no means all are allergic. I have seem estimates ranging from 30 to 50 percent of people are quite immune. So, if you have a large property, perhaps containing some land where people never go, you might consider not eradicating the poison ivy there. You’d be doing the wildlife a favor.