NOTES FROM THE ARNOLD ARBORETUM. The Restoration of Oak Path 294 A favorite walk of mine in the Arboretum is the Oak Path leading from a point on the Meadow Road nearly opposite the Centre Street gate and joining the Azalea Path on the southern slope of Bussey Hill. This walk leads past some of the first oaks planted in the Arboretum. Beautiful views toward the west of the Juniper dell and the Hemlock grove are obtained from it and it passes by some of the finest Azalea groups. It is a cool and shaded place in the summer and in the autumn canopied by vivid autumnal foliage. I think, however, I like it best in the springtime when the oak leaves are unfolding in soft grays, pinks and varying shades of red. (Wilson, E. H. 1925. America s Greatest Garden, p. 67. Boston: Stratford Co.) An intricate and extensive pathway system, offering both casual visitors and serious observers intimate access to the collections, was visualized by F. L. Olmsted in the original layout of the Arnold Arboretum. The concept was expanded upon and eventually carried out by Charles S. Sargent. The paths were unsurfaced and consisted primarily of broad, closely mown strips within a grassy ground cover that was otherwise mown but twice a year. A few of these pathways are still in general use; some have become access roads for our service vehicles. But most have been almost completely obliterated with time and with the practice of close mowing the ground cover. The original plantings beautifully complemented the varied terrain of the Arnold Arboretum, retaining the integrity of the major ecological habitat represented, which include deciduous and coniferous
A sectzon of Oak Path as it appeared in 1913. Photograph from the Arnold Arboretum archives.
296 forest, swamp forest, and meadow. We hope eventually, funds permitting, to restore the majority of the pathway system as part of our general restoration, and to define the paths as they were originally, by reverting to less frequent grass mowing along their borders than is currently practiced. Restoration of the pathways would encourage use of and provide access to some of the littleknown parts of the arboretum, of which Hemlock Hill is a noteworthy example. It would also give us the opportunity to expand and restore the existing collections along the pathways and to institute complementary interpretive collections for the general public. Keeping in mind our accessions policy of ultimately having each taxon represented by three individuals, each of a different wild accession, planting according to the Bentham and Hooker sequence will continue to be followed as long as space permits. In some cases, due to space limitations, only one of these three individuals of a particular taxon would be planted in the sequence. In other cases, particularly when the main collection of the group is in an ecologically inappropriate site, up to two individuals may be used out of sequence to enhance interpretive plantings. Individual plants would be sited to avoid visual clutter and to reinforce the structural integrity of each habitat. That is, tree groups would be underplanted or at least grouped with related shrub groups of similar ecological requirements. These plantings would be complented by native trees and shrubs characteristic of the habitat with masses of a few appropriate herbaceous plants. The use of native species would reinforce the essential naturalness of the Arnold Arboretum as Sargent and Olmsted originally intended. Restoration of the Oak Path has already begun. This path was the first chosen to be restored, partly because of its exemplary character and partly because its restoration will not involve major grading or structural costs. Fortunately, good documentation of its original condition is available through photographs and such descriptions as Ernest Wilson s quoted above. The enclosed map shows a tentative plan for the development of the lower portion of Oak Path and adjacent areas. The path begins in the Juglans or walnut collection, near the intersection of Bussey Hill and Valley Roads. The "grove" of black walnuts (Juglans nigra) presently consists of six individuals. It will be partially restored with the addition of four individuals from throughout the natural range of the species. The grassy area beyond the walnuts will be allowed to grow up into a meadow, through which the path will be cut. Seeds of the following meadow wildflowers will be introduced: blackeyed susan (Rudbeckia hirta) oxeye daisy (Chrysanthemum leucanthemum) asters (Aster ssp.) goldenrods (Solidago ssp.) gayfeathers (Liatris ssp.)
All necessary gradxng has been completed along Oak Path, and weed eradication is undenuay. A generous glft will enable us to plant herbaceous groundcover along tts borders. beebalm (Monarda fistulosa) penstemon (Penstemon digitalis) butterflyweed (Asclepias tuberosa) bluestar (Amsonia tabernaemontana) ironweed (Vernonia noveboracensis) In the oak collection itself, the path will proceed through an interpretive planting simulating an oak woodland with the oaks as canopy trees. Although this area will remain the primary focus of the Quercus collection, additions must be made judiciously as the site cannot support many more large trees without becoming cluttered. Further expansion of this important collection will be made on Peter s Hill. Understory trees are mostly absent now, but groups of flowering dogwoods (Cornus florida), redbuds (Cercis canadensis), and shadbushes (Amelanchier spp.) will be planted. The shrub layer will consist entirely of masses of American azalea species, extending the period of bloom of the large masses of flame azaleas (Rhododendron calendulaceum) already present, and beginning our general restoration of the Heath Family or Ericaceae in this area. Individuals will be selected from throughout the natural range of each species, insuring a maximum of genetic diversity; the area will eventually support our primary collection of American azaleas. Masses of selected species of native wildflowers typical of deciduous woodlands will complete the planting. As the path enters the oak collection, the herbaceous mas
September, September, 298 ses will consist entirely of goatsbeard (Aruncus dioicus). Anyone who has seen this species as it is naturalized under oaks in Olmsted Park in Brookline can appreciate the effect we hope to create. Further along the path three layers of herbaceous ground cover will be used in each of the masses. Plants to be used include lilyofthevalley (Convallaria majalis) and foamflower (Tiarella cordifolia), Solomon s seal (Polygonatum spp.) and false Solomon s seal (Smilacina racemosa), and bugbane or black cohosh (Cimicifuga racemosa). These can all compete with the grass, and all are shade tolerant, blooming at different times. Further along, masses of white trillium (Trillium grandiflorum), turk s cap lily (Lilium superbum), asters (Aster cordifolius), and other woodland herbs will be attempted. The lower portion of the path, from its beginning in the black walnuts will delimited simply by regular mowing of the grass. The surrounding grass will be allowed to grow naturally except for mowing each spring and fall. Shade will prevent it from growing so long as to look unkempt, but will allow it to grow long enough to make the mown path distinct. The grass was managed this way last year on an experimental basis with satisfactory results. The present openness of the oak collection, appreciable both from the Valley Road looking in, as well as from within the collection looking out, is one of its most appealing characteristics. We will maintain this character. The masses of azaleas under the oaks will be carefully planted to avoid clutter. The plant masses along the road will be situated so as to provide some visual barriers, but also to allow for sweeping vistas from under the oak stand, onto the azaleas on the upper slopes, rising to Bussey Hill. The proposed timetable for completion of the Oak Path is as follows: PHASE 1. Grading of the upper part of the path; removal of plants which are excess or in poor condition; mowing of the lower end of the path to establish its identity; establishment of a permanent mowed border. Projected completion: August, 1980. PHASE 2. Eradication of Rubus and other perennial weeds in the existing groups of azaleas both manually and by the judicious application of herbicides. Projected completion: immediately along the path September, 1980; throughout the oak collection 1981. PHASE 3. Establishment of two areas of meadow. Projected completion : initial plowing June, 1981; soil preparation, final plowing, seeding 1981. PHASE 4. Establishment of other herbaceous masses. Projected
September, June, 300 completion: plant acquisition 1981; bed preparation and planting 1982. PHASE 5. Establishment of azalea masses gradually as the plants become available. Wildcollected plants in our living collections have been propagated and will be ready for planting in 1982. Other plants will be wildcollected in 1982 and will be ready in 1983. Plants grown from seed wildcollected in 1980 and 1981 will be ready in 1984 and 1985. Projected completion: June, 1985. RICHARD E. WEAVER, JR. Back cover: A view from Willow Path across the meadow, after its annual mowing in October. Photograph by C. Lobig.