Rhododendrons: Rosebay Rhododendron (Rhododendron Maximum)

This is the second in a series of posts in which we will take a look at some of our native North American Rhododendrons.  Rhododendrons (and their happy sub-genus, Azaleas) occur throughout the continent except on the Great Plains, the eastern interior plains (southern Michigan, western Ohio, Indiana, Illinois, etc.), and all of Mexico other than the mountains of northern Baja California.

While I maintain that Catawba Rhododendrons are amazingly beautiful and something that every true plant lover should make a pilgrimage to see at least once, the Rosebays have a special place in my heart.  They grow all the way up to Quebec and Nova Scotia and might have once covered more territory in Ontario.  For a broadleaved evergreen, they laugh at the face of winter cold, more so than even the mountain-top hugging Catawbas, but they also have limitations.  Like the domestic cultivars of the genus popular in gardens, the Rosebay is not really fond of the hot sun of the afternoon.  They also don't tend to get a lot of attention from gardeners outside of their home region of the Appalachians, which is a shame because they can be every bit as impressive in flower and scale as their Catawba cultivar cousins.  Like the Catawba, they are properly considered a tree, having every bit the stature of one.

Great Smokey Mountains National Park, alongside the Newfound Gap Road along the Oconaluftee River in North Carolina.

That said, it tends to take on a bit more delicate of a branching structure than the mighty Catawbas.

The slender trunks of the Rosebay stand out in individual specimens.  This one was found at Cumberland Gap National Historic Park in Kentucky, along the Pinnacle Overlook road.

Like the Catawbas, it can and often does form pretty impressive forests in its own right.

Along the Oconaluftee River in North Carolina.

The difference here, however, is that they don't like the same degree of exposure that the bald species do.  This probably owes to the fact that they are a more intermediate elevation rhododendron, which in the southern portion means that summer brings much warmer temperatures, and anywhere in its range means comparatively less available moisture for the plants.  As a result, one will find Rosebays among the forests, where they can even form a secondary canopy in places that they tend to dominate.  In the southern Appalachians, especially in the Smokies and along the Blue Ridge, they really do dominate, perhaps even to the exclusion of other plant life on the forest floor, an invasive native if you will.  

Along the Blue Ridge Parkway, somewhere between Spruce Pine, NC and Mt. Mitchell.

Same as above.

Still, they do form a lovely understory, and fit in in a variety of surroundings, be they drier forests of oak and pine, where they are less common, and moister, northern forests of beech, maples, and hemlocks, where they can found at home both in the central and northern Appalachians and the Cove Forests of the southern Appalachians which duplicate these conditions in an otherwise much warmer setting.

A cove forest, but I don't recall where exactly.

They seem to perform the best, or at least occur almost without fail, along streams, especially in forests of Hemlock and associated trees.  Here they help to make for an incredible lushness in a darker green setting and reach proportions of size that put the Catawbas to shame.

Along the Oconaluftee River in North Carolina, in Great Smokey Mountains National Park.

Same place as above.  That Rosebay in the left background up there was half the size of some pretty decent trees, well over 30 feet tall.

And speaking of size, they are not called Rhododendron Maximum as a joke.  Their leaves are the biggest of any Rhododendron in the world.  They can usually be identified by these long, relatively narrow leaves even when not in flower.  Herein also lies their main attraction for this particular gardener: huge evergreen leaves that can take northern winters.

Same location as above.

And yes, they flower as well as a Catawba does, in the same big globe clusters, albeit sometimes not always at once, and not necessarily as prolifically.  They also take their time flowering, flowering as early in the southern ranges as March and continuing up into August pretty much everywhere.

These first two were taken off the same plant, again along the Oconaluftee River in North Carolina in that amazing National Park.

This one was found at Cumberland Gap National Historic Park in Kentucky, again along the Pinnacle Overlook road.

All in all, a nice, if not as dramatically special Rhododendron that the Catawba is.  They certainly are more common, and in some places it was hard to miss them.  I have yet to find some of their natural populations further north, where they do thin out a bit more in comparison to the thickets of the south, but they are pretty common as escapes from cultivation, and they can even get weedy in character as they like to take advantage of disturbed areas, something odd for a plant that likes being cool, moist, and shaded.  

A chance meeting near a highway widening project, where land looks to have been opened for some time, along Gap Creek Road near Elizabethton, Tennessee. 

This was the canopy above those Rosebays, which this far south means drier conditions than they would normally frequent.  Eastern White Pines (Pinus Strobus) are a true northern species, but down here they seem to also make a lower-middle elevation home among the dry and hot conditions favored by oaks.  I would figure sand would have something to do with it.

One can find tons and tons of them along I-80 in Pennsylvania, especially on the stretch between I-81 and I-476:

Many more where this came from.  Sorry for the blur.  This was in the thirties in February, and they did not really look overly concerned about the cold.

To return to the White Pine picture for some closing comments, I have to wonder about just how widespread these things used to be.  Current botanical thinking is that they are opportunists that have taken advantage of artificial changes brought by humans in modern forest settings, akin to how the Eastern Red Cedar (Juniperus Virginiana) is more prevalent than it once was.  While I don't argue with the evidence that backs up this line of thinking, because they really do tend to be opportunistic for a Rhododendron, the evidence also focuses on disturbed conditions, and in some decent growth forests they still do form an integral part of the scenery.

My thinking is, owing especially to their tolerances and favored conditions (I mean come on, they can handle cold just fine and they can pop out of rock hillside soil like its made of Miracle Gro), they were perhaps once a feature of forests in Ontario and decently into the Canadian Shield.  They do grow in upstate New York and Quebec, including parts of the Adirondacks and even Erie County, where urban development in Buffalo has probably removed a bunch of the wild population (I would looooove to find some if anyone knows of any wild ones there).  I could imagine that perhaps once, along with maybe Prickly Pear Cacti, grew happily in the sands of eastern Ontario below towering White Pines.  Sure, they might colonize disturbed areas bearing such conditions, but they are no stranger to somewhat dry pine lands, as this particular part of Connecticut demonstrates:

The Most Unusual Natural Area of Connecticut

Oh, and they are also movie stars, as far as plants go.  You can see a few flowering ones in the woods during the opening running scene in Last of the Mohicans!

Tomorrow we shall come across something a little different, an azalea!