THE HEDGE GARDEN Rehabilitating an Arboretum Treasure

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THE HEDGE GARDEN Rehabilitating an Arboretum Treasure By Scott Mehaffey, Landscape Architect When I reported for work in early September 1993, I learned that most of my time over the next few years

1 THE HEDGE GARDEN Rehabilitating an Arboretum Treasure By Scott Mehaffey, Landscape Architect When I reported for work in early September 1993, I learned that most of my time over the next few years would be devoted to Master Planning and revitalizing our Horticulture Display Gardens--both formidable tasks! I soon witnessed firsthand how frequently these gardens are used by our members and visitors and was reminded of the need to make them reflect current landscape trends and styles. We chose the Hedge Garden for our first rehabilitation effort because 1994 marks its 60th anniversary. The Hedge Garden as it appeared in the late 1930s. 49

50 History and Association with the Morton Family As early as 1928, the Arboretum's Bulletin of Popular Information listed recommended deciduous and evergreen hedges.

2 50 History and Association with the Morton Family As early as 1928, the Arboretum's Bulletin of Popular Information listed recommended deciduous and evergreen hedges. During the spring of 1931, the Arboretum set up a "Test Hedge Collection" of 54 species where the east end of Meadow Lake is today. By July of 1934, workers had planted 109 hedges there. That fall, they transplanted the entire collection 250 yards south to its present location. Superintendent Clarence Godshalk (before he became Director) recalled in his journal, "The Hedge Garden design was a composite of suggestions by Mrs. Cudahy, Holabird & Root, the Superintendent [Godshalk] and the Arboriculturist [E. Lowell Kammerer]." Architects Holabird & Root had just broken ground for the Administration Building, and the new Hedge Garden was planned to anchor the building in its then largely unplanted surroundings. After her father's death in May, 1934, Jean Morton Cudahy became Chairman of the Board of Trustees and served until she passed away in The Hedge Garden was one of her earliest projects, and was planned on the scale of a grand European estate garden. A one-third-mile axis began in a circular, graveled motor court behind the new Administration Building, traversed the Hedge Garden, and continued along a Spruce allee through the new Pinetum then being planted on Frost Hill. From the motor court, two short segments of privet hedge led to an opening that featured a circular bed of low junipers. The privet hedges continued east, creating three garden "rooms." In these rooms display hedges flanked a center terrace where low beds of junipers surrounded a specimen 'Pfitzer' juniper. Dwarf conifers accented the comers of each room. At the east end of the garden, a cross-axis opened onto the meadow to the north and the new juniper and yew collections to the south. Here, flagstone steps and grass walks surrounded another circular bed of Pfitzers, forming an effective terminus to the garden and marking the Pinetum's main entrance. Overall, nine terraces ascended the west face of Frost Hill, all separated by rustic flagstone steps. At the far east end, a flagstone seat/wall built into the slope, provided a place to enjoy the vista back to the west. In 1936, a "Garden of Old Fashioned Roses" was incorporated into the center terrace, once again a composite of ideas from Mrs. Cudahy and Clarence Godshalk. Low clipped, hedges of upright barberry formed a "knot" or "parterre," recalling formal French gardens of the sixteenth through eighteenth centuries. Inner rows of Chinese elms, sheared as box-like "topiary," complemented the formal hedges, and an outer row of 'Moline' American elms helped frame the view. In the 1940s, workers replaced the Chinese elms with upright Washington hawthorns, and planted several rows of additional display hedges to the immediate sou th of the garden. In 1953, Sterling

3 Morton became Board Chairman, and the Arboretum strengthened its focus on research. In 1954, the staff set up "Experimental Hedge Plots" to test the effects of leaf stripping, study salt tolerance, and record shearing intervals and reactions to fertilization. At that time, they replaced the privet hedge that surrounded the Hedge Garden with burning bush in order to reduce the shearing frequency and to provide a denser hedge. They also replaced the low barberry hedges in the center terrace with littleleaved Korean boxwood. When the first Research Wing was added to the Administration Building in , an auditorium (named for Mrs. Cudahy) and a Rotunda were built over the gravel motor court at the west end of the axis. This building complex was renamed "The Arboretum Center," and housed restroom, gift, and restaurant facilities until the opening of the Visitor Center in This complex was essentially the Arboretum's "front door"-where the visitor's first impression was made-and "The Four Columns," commissioned in 1960 by Sterling Morton's daughter, Suzette Morton Davidson (Board Chairman ), made a spectacular focal point for the impressive view from the Rotunda. The Rotunda's exposed aggregate terrace and the lily pond at the Administration Building's north door were built in 1961, and the Sterling Morton Library was added in By the 1940s, when this photo was taken, the Hedge Garden was fulfilling its promise as a great formal landscape in the European tradition. 51

4 REHABILITATING THE GARDEN One of the least-used elements in the modem landscape is the sheared hedge. In our busy workaday lives, there is little time for any yard work other than mowing and seasonal clean-up. Current landscape trends call for plants that flower, attract wildlife, and provide screening from our neighbors and the street. These needs can be met by using informal hedges that require only occasional pruning. And yet, in formal landscapes, sheared hedges remain one of the classic elements. They are often used today in "period" landscaping for historic houses and buildings or with modem architecture where they are used to extend geometric mass into the landscape. Although they require additional care, sheared hedges can also benefit homeowners with small yards or tight spaces, where screen plantings must be kept tall and narrow but interesting to the eye. Although the Arboretum maintains an extensive archives, we have not been able to locate the original plans for the Hedge Garden. However, later plans drawn by my predecessor, Landscape Architect Tony Tyznik, and historic photographs document the overall bed layout. Period issues of the Arboretum's Bulletin of Popular Information provide more detailed information about the performance of hedge plants. Using these photographs, plans, and old articles together with a knowledge of the limitations of the site, we prepared drawings and plans for the renaissance of the Hedge Garden. In spring 1994, workers staked the plant beds and straightened their lines. 52

5 Workers then rototilled the plant beds (top photo) in preparation for the arrival of new plants (bottom photo). 53

6 To keep the new plants fresh, workers submerged their roots in large holding tanks prior to planting. 54

7 Keeping these factors in mind, Collections & Grounds Program staff evaluated the Hedge Garden in the fall of 1993 and determined which of the hedge selections were no longer in their prime or useful to contemporary homeowners. They removed several hedges by cutting plants to the ground and lifting roots with a backhoe. They also removed a double row of sixteen columnar Washington hawthorns which once echoed the shape of the distant "Four Columns." Their proximity to the juniper collection had intensified the effects of cedar-hawthorn rust and the trees had become malformed from constant pruning to remove dead wood. Over the winter, the staff created a list of trees and shrubs for hedge use based on form, flower, foliage, fruit, and bark characteristics. We also studied the history of the Hedge Garden itself, which despite frequent changes, is believed to be the oldest continuous hedge display among arboreta and botanical gardens in the United States. This spring, the garden was abuzz with the efforts of our horticulturists. In early March, we pruned the remaining hedges and rejuvenated many by cutting them to the ground and removing the largest stubs. We renewed others by selectively removing the largest canes and shaping the plants to a manageable height and width. Using the drawings as our guide, we staked the planting beds, and, as bareroot plants began to arrive in early May, we deep-tilled the beds and raked them out. We then planted the new trees and shrubs on centers of either twelve, eighteen, twenty-four, or thirty inches. We replaced the inner rows of columnar hawthorns with eight pairs of matched fastigiate European hornbeams. Finally, we mulched all beds and the surrounding burning bush hedge with six inches of shredded and aged hardwood bark, and installed an interim irrigation system of three-quarter-inch, low-density polyethylene drip lines in the mulch layer under all hedges to provide supplemental water during the first few critical years. During the winter of , several of the new hedge plants will be cut to the ground to encourage dense regrowth. It may take a few years before the garden appears at its best, but we think the results will be outstanding. The rehabilitation* required few alterations to the original design. We incorporated 1960s-era benches, previously scattered throughout the garden, into the west terrace in a new seating area that echoes the design of the cross-axis at the far east end. We shortened display hedges slightly to reduce maintenance, and the upper terrace (furthest from the Rotunda) now displays unsheared hedges which may be more relevant to contemporary homeowners. In the coming years, plans call for renovating the seat wall overlook at the far east end of the Spruce allee, and the center terrace of the Hedge Garden. *According to the Secretary of Interior's Guidelines for the Treatment of Historic Landscapes, "Rehabilitation retains the landscape as it has evolved historically by maintaining and repairing historic features, while allowing additions and alterations for contemporary and future uses." 55

SHEARED HEDGES 111111111111111 To Administration Building ~ 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 111111111111111 IL NA BR Q c T Species is native to

8 SHEARED HEDGES To Administration Building ~ IL NA BR Q c T Species is native to Northern Illinois Species is native to North America Relatively easy to purchase and establish bare-root specimens Not favored by deer Showy autumn coloration Thorny, either stems or leaves making good barrier planting Location Scientific Name bed 1: Cotoneaster (genus only is known) bed2: Berberis thunbergii 'Rose Glow' bed3: Thuja plicata bed4: Tsuga canadensis bed5: Taxus X media 'Timber Creek' bed6: Quercus imbricaria bed 7: Euonymus fortunei 'Sarcoxie' bed8: Malus sargentii bed9: Aronia melanocarpa var. elata bed 10: Fagus sylvatica bed 11: Ligustrum vulgare 'Cheyenne' bed 12: Itea virginica bed 13: Cotoneaster lucida bed 14: llex opaca 'Hedgeholly' bed 15: Ribes alpinum bed 16: Buxus 'Glencoe' bed 17: Teucrium chamaedrys bed 18: Cotoneaster acutifolia bed 19: Acer campestre bed 20: Fontanesia fortunei 'Titan' bed 21: Viburnum lantana bed 22: Carpinus betulus bed 23: Cornus mas 'Golden Glory' bed 24: Pinus strobus bed 25: Euonymus alatus 'Nordine' bed 26: Viburnum dentatum bed 27: Physocarpus intermedius f. parvifolius bed 28: Thuja occidentalis 'Smaragd' bed 29: Acer ginnala 'Compactum' bed 30: Crataegus phaenopyrum KEY to symbols, abbreviations, and categories E F L N w Evergreen, retains leaves throughout the winter Particularly attractive and/ or fragrant in flower Useful as a low hedge; can be maintained below 3' height Can be maintained as a narrow hedge (usually sheared) Fruit attractive to birds and other wildlife Planting trial considered experimental Existing hedge to remain (Lower Terrace near Administration Building) Common Name Cotoneaster* Rose Glow Japanese Barberry Western Arborvitae Eastern Hemlock Timber Creek Yew Shingle Oak* Sarcoxie Winter Creeper Sargent Crabapple* Black Chokeberry European Beech Cheyenne Privet Virginia Sweetspire Hedge Cotoneaster* Hedgeholly American Holly Bailey Alpine Currant Chicagoland GreerlM Boxwood Wall Germander Peking Cotoneaster* Hedge Maple* Titan False Privet Wayfaring Tree* European Hornbeam* Golden Glory Dogwood Eastern White Pine Nordine Burning Bush Arrowwood Viburnum* Ninebark* Emerald American Arborvitae Compact Amur Maple Washington Hawthorn Features/Remarks C, Q,C, T, L, W NA,Q,E NA,Q,E E, L,? IA,? E w IL, NA, BR, C, F, W,? Q, BR,F,,W NA,C,F,? C, NA,Q, T,E BR, Q,E, Q,,? BR,W C,F,N IL, NA, BR, E c NA, BR, C, F, W NA,BR IL, NA, BR, E, N c NA,C,W 56

I UNSHEARED HEDGES - 1 11111111111111 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 11111111111111 ToPinetum I The rehabilitated Hedge Garden serves as a practical

9 I UNSHEARED HEDGES ToPinetum I The rehabilitated Hedge Garden serves as a practical contemporary resource for people seeking information about hedges and how to use them. This impressive garden echoes many historical design traditions and provides a beautiful and inspirational setting for Arboretum visitors. This highly successful first rehabilitation project sets the tone for revitalizing many of our horticultural displays in the years ahead. (Upper Terrace near Pinetum) Location Scientific Name bed 1: Viburnum dentatum 'Ralph Senior' bed 2: Berberis thunbergii 'Atropurpurea' bed 3: Spiraea trilobata 'Fairy Queen' bed 4: Syringa meyeri 'Palibin' bed 5: Berberis thunbergii 'Erecta' bed 6: Berberis X mentorensis bed 7: Berberis thunbergii 'Atropurpurea Nana' bed 8: Rosa 'Meidomonac' bed 9: Rosa 'Hansa' bed 10: Spireaea X bumalda 'Goldflame' bed 11: Calycanthus jloridus bed 12: Cornus pumila bed 13: Ilex verticillata 'Afterglow' bed 14: Forsythia 'Meadowlark' bed 15: Thuja occidentalis 'Holmstrup' bed 16: Ribes alpinum 'Pumilum' bed 17: Cornus stolonifera 'Isanti' bed 18: Viburnum trilobum 'Bailey Compact' bed 19: Taxus cuspidata 'Nana' bed 20: Buxus 'Green Mountain' bed 21: Ilex glabra 'Chamzin' bed 22: Taxus X media 'Brownii' bed 23: Myrica pensylvanica bed 24: Lonicera X xylosteoides 'Clavey's Dwarf' bed 25: Physocarpus monogynus bed 26: Prinsepia uniflora var. serrata bed 27: Spireaea X bumalda 'Anthony Waterer' bed 28: Clethra alnifolia Common Name Autumn Jazz Arrowwood Viburnum Redleaf Japanese Barberry* Fairy Queen Bridal Wreath Palibin Lilac Truehedge Columnberry* Mentor Barberry* Crimson Pigmy Barberry Bonica Rose Hansa Rose Goldflame Spirea Carolina Allspice Dwarf Dogwood Afterglow Winterberry Meadowlark Forsythia Holmstrup American Arborvitae Dwarf Alpine Currant* Isanti Dogwood Bailey Compact Cranberrybush Dwarf Japanese Yew* Green Mountain Boxwood Nordic Inkberry Brown Yew* Bayberry* Clavey's Dwarf Honeysuckle* Mountain Ninebark* Hedge Prinsepia* Anthony Waterer Spirea* Summersweet Features/Remarks NA, BR, C, F, W.12 C, T, L, W BR,D,F.12 F.!2,C, T, W.12 T, N.!2,C, T, T,F,W,? T,F, W BR,.12 C, F, L, N NA,.12 F.12 C, L IA, W BR,.12 F IL, NA, BR, E, N IA, BR, W IL, NA, C, F, W,? E,L.12 E, L, N.12 E,? E NA,Q BR NA,BR F,L BR,.12 C, F, L, N NA,F 57

ARBORVITAE, MR. BOWLING BALL Thuja occidentalis Bobazam

ARBORVITAE, MR. BOWLING BALL Thuja occidentalis Bobazam ARBORVITAE, HETZ MIDGET Thuja occidentalis Hetz Midget Height: 2-3 Spread: 2-3 Color(s): green A dark green, slow growing, compact, globe shaped evergreen that maintains its shape without trimming. Water