Rhododendrons in New Hampshire
By Gordon Emerson, Rock Creek, Ohio
When you're traveling on a time schedule you take your mountains as you find them. It had been raining the day we drove up Mt. Washington and the top 1,500 feet was shrouded in cloud. This meant we would not be able to look across the several hundred miles of the state of Maine and perhaps catch that glimpse of the Atlantic Ocean which is reputed to be possible on a clear day and which attracts hordes of tourists to this point in north central New Hampshire. I was much less interested in vista-gazing than in viewing Rhododendron lapponicum and other high alpine plants in a wholly natural setting. I suspect the rest of the family would have preferred a few minutes of staring into the distance to tramping about in the foggy, foggy dew and clambering over granite boulders.
Fig. 30. R. lapponicum growing in the author's garden in association
with the dwarf cinquefoil and on of the grasses with which the
species is associated in its range on Mt. Washington.
Fig. 31. R. maximum in the author's
garden, showing the fine foliage and
graceful growth of the species when it
is free to develop as a specimen.
Fig. 32. R. catawbiense in typical
form, with R. maximum var.
leachii at lower right.
R. catawbiense is about five ft tall
at 10 years while the R. maximum
variety is about two feet at 12 yrs.
The elevation of Mt. Washington is 6,288 ft., just 396 ft. below that of Mt. Mitchell in North Carolina, the highest peak east of the Mississippi. Because of the northerly latitude, Mt. Washington and the other high summits in the Presidential Range of the White Mountains have extensive alpine regions of a true arctic character, whereas Mt. Mitchell is tree-clad to the summit. The tree line on Mt. Washington is at about 4,800 feet and the heights are battered by some of the cruelest weather, winter and summer, of which the mind can conceive. A plaque on the weather observatory building at the summit notes that wind of the highest velocity ever recorded on this planet - 231 miles an hour-was clocked here.
We drove up June 24. The temperature at the base was 68 degrees. At the top it was 47 degrees. The previous day there had been a sleet storm of sufficient intensity to coat everything with up to a half inch of ice and to turn the clothing of hikers into board. A few small pockets of winter snow were to be seen hither and yon along the roadway.
To get to the summit you have three choices: the rugged hiking trails, a cog railroad which might be compared to a slow roller-coaster, and the eight mile long toll road which is also of a thrill-a-minute design. After the first mile or so there is no straightaway of more than a couple of hundred feet duration, and not a yard is level. You drive in the lowest gear you can shift down to-which isn't low enough to drag some heavy cars with automatic transmissions up the grade. Just wide enough, enough for two cars to pass, the road is half-paved, half gravel, the paved sections being the banked curves for the most part. Once you get above the tree line the vistas are awesome, for the roadway snakes along the edge of the steeps and crawls over narrow ridges. By contrast the roads up Mt. Mitchell and through the Big Horn Pass in Wyoming are lush freeways.
R. lapponicum reputedly is a common part of the flora of the Arctic regions of North America, Europe and Asia. Botanical literature notes that it may be found in a few other limited locales, including Mt. Washington and Wisconsin Dells, Wisconsin. The impression is that it is a relatively rare plant in these special locations, and I was prepared to do considerable scouting.
It is true that R. lapponicum is confined to a tiny portion of the mountain and that the mountain represents little more than a dot on the map; but in the territory in which it may be found the species is by no means rare. It virtually blankets the upper third of the alpine region of the peak. Naturalist tracts and other reference literature picked up in the area indicates the species may be found on the other higher peaks in the White Mountains and occasionally in the Adirondacks of New York State.
On June 24 R. lapponicum appeared to be at about the middle of it blooming period, with some plants at the highest elevations having some buds unopened and at lower elevations only a scattering of flowers in evidence. The ice storm of the previous day appeared to have had no effect on the opening buds and had not destroyed the flowers which had been open, merely ruining the texture. Nowhere in the several acres of rugged terrain over which we tramped did we find a plant which appeared to have flowered profusely; in fact, most appeared to have had no bloom. In the misty atmosphere, with visibility limited to about 50 feet and clear visibility to less than six feet, it was difficult to judge color. Blossoms taken back to "civilization" were found to be of the same shade of reddish purple as is indicated in color photographs of the species. There seemed to be little variation in color or flower size, this being about a half inch, or in flower form, all having a rather raggedy appearance due to the uneven flattening of the corolla. Some variation in leaf size and shape was noted but the variation was not remarkable. Generally the foliage was a deep, dull green.
As noted in botanical literature, the species is usually seen as a prostrate plant, with an occasional specimen in the lee of a rock or otherwise protected from the wind, perhaps reaching a foot in height. Just how prostrate R. lapponicum can grow is difficult to envision. At the highest elevations the foliage rises barely an inch above the soil level, with branches and stems lying flat or actually buried in the soil. At the lowest elevations growth is a little more free but we did not find any that stood more than two inches high.
Soil at these high elevations consists almost wholly of humus, although the slow decay of the rock through the erosion of wind, rain and freezing, must contribute to it. It is confined to shallow pockets rarely more than a few yards across. One would have difficulty in scooping up as much as a thimble full of free soil. The roots of R. lapponicum and the other plants permeate literally every square inch, creating a porous, spongy medium which has the feel of thick carpet when stepped upon. Cracks in the rock provide perfect drainage so that even on a rainy day you will not find any thing of the texture of garden mud.
Failure to successfully cultivate this species doubtless relates to the difficulty of providing not only cool, moist atmospheric conditions, but a growing medium which will remain constantly moist without retaining excess water, compacting or "souring."
At the highest elevations the more profusely distributed companion plants are the pincushion flower (Diapensia lapponica), a dwarf herbaceous cinquefoil, bearberry, several species of miniature Vaccinium including V. vitis-idaea, willow (Salix) and several distinct types of grasses. The various types of vegetation intertwine, with only the pincushion flower being commonly isolated from the general tangle, it apparently thriving on thinner layers of less humusy soil which would not support the woody plants. Tangles of grayish lichen of the type commonly seen on trees in the north woods are interwoven with the foliage everywhere. Other types of lichen and mosses may be found on rock surfaces, these helping with the production of soil.
Because of their prostrate habit, all of the woody plants are constantly renewing themselves through layering. The rate of growth is extremely slow. A particularly vigorous R. lapponicum may put out an inch or slightly more of new growth in a season, but typically it would appear to be a fraction of this. In tracing a particular plant back to its point of origin one could easily come to the conclusion that it has persisted for hundreds of years. Possibly some are thousands of years old, even perhaps being the remnants of the first R. lapponicum which took root on the mountain, the older parts dying and becoming part of the humus feeding successive generations of self propagated new plants. Here and there is evidence of the process-clumps of weathered dead wood with branches radiating toward groups of thriving young plants.
At the lower elevations at which R. lapponicum may be found the range of companion plants is more varied. There is still a profusion of bearberry, the several species of Vaccinium, Salix and grasses, etc., all growing more lushly. Labrador Tea (Ledum), the red heather (Phyllodoce empetriformis), sheep laurel (Kalmia angustifolia), and representatives of other genera appear, and then become the dominant vegetation. Ledum eventually replaces R. lapponicum in the ecological scheme, and plants common to the lowlands begin to appear, like the bunchberry (Cornus canadensis) which in late June covers the mountain and valley roadsides with drifts of snowy white. In the highlands, the flowers (bracts) are pale yellow, at least in their initial stages, and not at all showy.
The ruggedness of the Mt. Washington climate is evidenced by the occasional seedlings of birch and fir which may be found hundreds of feet above the elevation at which the last stunted, gnarled trees are found. These seedlings persist perhaps a year or two and then perish, contributing to the humus. Doubtless windborne debris from lower elevations and other mountains-seeds that never germinate, seed husks, leaves, insects, dust, etc.- help maintain soil quality and quantity.
One comes down Mt. Washington much more quickly than one goes up and the roadside fall-away does not loom nearly as threateningly once one has wandered about a bit on foot. The scrub fir appears, nearly prostrate at first, the tallest no higher than the surrounding tumble of rock, but growing taller and more upright with each turn in the road, until suddenly the road is cutting through forest.
At the lower elevations we caught glimpses of several plants of the Rhodora (R. canadense) in full bloom. At home in northeastern Ohio R. canadense flowers in late April or earliest May. We stopped to inspect one plant growing in the road ditch. The two trusses each had 10 to 12 florets of rather typical purplish color and size. The foliage gray with hardly a hint of green and densely hairy, much like a plant I collected about 10 years ago in Maine. The collected plant has gradually lost nearly all of its hirsute character and retains only a blush of its gray leaf color. Over the years the intensity of the flower color also has diminished. Possibly the extreme hairiness of the Mt. Washington plant is related to climatic conditions.
Two days prior to the trip up Mt. Washington we visited Rhododendron State Park in southwestern New Hampshire. The park preserves a natural stand of R. maximum, a foot trail of about a half mile(?) winding through the groves. The plants are typical of the species as it is represented north of the Mason-Dixon line, rather lanky, open growing shrubs eight to 10 feet tall, with excellent foliage. On that date (June 22) perhaps one out of 20 plants were showing some bloom, mostly of the typical blush pink in closely-packed small trusses, although here and there were flowers of deeper color and some nearly pure white. As in most stands of R. maximum this writer has observed in Pennsylvania, West Virginia, Virginia, North Carolina and elsewhere, there were virtually no young plants and seedlings were few. Doubtless many young plants are lost to collectors, both amateur and professional. But a peculiarity of the ecology relating to the species may also be involved. Renewal through seedlings may not get its thrust until disaster threatens the stand of mature plants; that is, until an opening is forced in the primary area of distribution. In a number of locations elsewhere I have found small plants (under three feet) and seedlings some distance from the stand of old plants while immediately adjacent to the stand there were few or none.
The day following the ascent of Mt. Washington we stumbled upon the finest flowering R. maximum that I have seen or heard described. It was in a planting in front of a library in a hamlet in central New Hampshire. Stopping at the library (the only public building in the town) to inquire about the location of the nearest decent restaurant, I was first taken by a planting of a half dozen or so Kalmia latifolia of extraordinary beauty; so taken that I nearly passed by a planting of a like number of young R. maximum at the opposite side of the walk. All were starting into flower, with all displaying one or more partially-opened truss of typical form and color except the one. This had a full-opened truss of a pink as deep as R. 'Roseum Elegans' but with out the blue admixture; a clear, vibrant pink, with florets considerably larger than typical R. maximum, held much in the style of the best forms of R. catawbiense. My first thought was that it was a hybrid of the R. 'Russell Harmon' type. Close inspection quickly established that if it was a hybrid there was no clue to it in growth habit, bud, leaf, etc.
Two cuttings were received through later correspondence but little information about the origins of the plant other than it had been collected in the wild for the local landscaper; the "wild" might have been anywhere between Maine and Georgia.
In slicing the cuttings to make green grafts, I discovered the cambium layer to be of a rich pink of nearly the same intensity as that of the flowers. Close examination of the leaves revealed them to be densely hirsute top and bottom, quite felty below. In the juvenile stage the hair was a pinkish buff. As the one surviving graft hardened off the leaves lost much-but not all-of the hirsute character and the pinkish cast became less pronounced. A pinkish blush on the soft wood also became less pronounced with hardening off.
The plant brings to mind the often referred to stand of red R. maximum on Mt. Mitchell, the sap of which even is reputed to be red. The Mt. Mitchell reds lose their pigment when removed from their natural locale. It will be interesting to see whether the New Hampshire pink also loses its distinctive pigmentation. This writer will be pleased if it merely retains its distinctive truss.
We had one last glimpse at representatives of the genus before heading home. This was a day or two later at the Shelborne Museum at Burlington, Vt. Here there was a large new, planting of R. mollis hybrids, well planted and in excellent condition. A few still had scattered blossoms. Tags on the individual plants indicated they were from a nursery with controlled breeding program, the plants being either numbered or bearing the names of the parents.
Burlington, Vt., is considerably further north than azaleas of any type are generally grown. It is gratifying to find that someone in that general area is at work developing hybrids of the genus Rhododendron suitable for that region.