Executive SummaryEnvironmental Management Study for

WINTERTHURMuseum, Garden & Library

New Castle County, Delaware

withPatricia Ann Quigley, Inc.

andHyla Associates

February 2000

NATURALLANDSTRUST

Acknowledgements

This project was funded by the Delaware Department of Natural Resources andEnvironmental Control, Project Manager: Stephen N. Williams, P.G., WholeBasin Coordinator

Team Members

Natural Lands TrustHolly M. Harper, R.L.A. ............................................. Project Manager/Stewardship PlannerDavid Steckel ..............................................................Director of Natural Resource ManagementD. Andrew Pitz, R.L.A. ........................................................ Director of Conservation PlanningDiane Rosencrance...................................................................................................... Planning AssistantClaudia Steckel ............................................................................................... Consulting Horticulturist

Patricia Ann Quigley, Inc.Patricia Ann Quigley .................................................................. Project Manager/Senior BiologistChristopher Mulvey ......................................................................................................... Project BiologistSarah Willig ........................................................................................................................... Project Biologist

Hyla AssociatesJames F. White, Jr. ............................................................................................................................ President

WWinterthur is an American garden and grounds representing a naturalisticstyle of landscape design based on the rural landscape of the BrandywineValley. It is of cultural and botanical interest as it is the repository of many

of the finest plants available during the first half of the twentieth century, and itreflects an American horticulturist’s interest in the ideas of “wild gardening” adaptedfrom Britain to an American setting. Winterthur, an historic garden and grounds ofnational importance and international concern, represents an example of an Americancountry place and garden and grounds created by an individual of exceptional talentand taste. …

Winterthur is committed to conserving the former estate and residence of HenryFrancis du Pont, who created a major museum of American decorative arts, displaygardens embodying his concept of artistic gardening and grounds. The museum andgardens and grounds are interrelated as a totality and are connected by a commonthread of taste, design, style, and color. The Board of Trustees recognizes thatWinterthur is unique among American educational institutions open for theenjoyment of the public. The original design of the gardens and grounds has beensubstantially retained over the years. It is Winterthur’s policy to conserve this designfor posterity, while recognizing the elements of change inherent in living organisms. …

Winterthur pursues a policy of professional management capable of makinghorticultural, conservation, maintenance, and related decisions commensurate with therarity and complexity of the gardens and grounds. This policy assures that Winterthurcan take advantage of future opportunities which may arise in the continueddevelopment and appreciation of its historic resources.

The Board of Trustees recognizes that its gardens and grounds are an educationalresource for the public. It is Winterthur’s policy to interpret the gardens and groundsto the public. This interpretation should foster a greater understanding andappreciation of landscape design, plant combinations and garden history. The Board iscommitted to making the garden and grounds as fully open and accessible to thepublic as resources allow. …

From the Board of Trustees Policy and Guidelines forWinterthur’s Gardens and Grounds, May 1987

W

INTRODUCTIONWinterthur Museum, Garden and Library, the former countryestate of Henry Francis du Pont (1880–1969), is a ±966 acreproperty located approximately five miles northwest of the city ofWilmington in New Castle County, Delaware (see Figures 1 and2). The property features a museum filled with du Pont’s collectionof American decorative arts made or used in America between1640 and 1860; a 60-acre naturalistic garden, considered one ofthe world’s finest, that represents the artistic vision of it’s creator,H. F. du Pont; and a research library for the study of American artand material culture.

Meadows, woodlands, hedgerows, and ponds and streamscomprise almost 70% of the Winterthur property. The steeplyrolling topography is covered with native grass meadows andprimarily native hardwood forests, many of which can be classifiedas old growth (>150 years old). Clenny/Wilson Run flowseastward through the property to the Brandywine Creek and

ExecutiveSummary

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Environmental Management Study for

WINTERTHURMuseum, Garden & Library

New Castle County, Delaware

NATURAL LANDS TRUSTHildacy Farm1031 Palmers Mill RoadMedia, Pennsylvania 19063610-353-5587

with

PATRICIA ANN QUIGLEY, INC.1080 Quarry Hall Road. R.D. #1Norristown, Pennsylvania 19403610-584-1829

HYLA ASSOCIATES1011 Center Mill RoadHockessin, Delaware 19707302-652-1952 N

orth

Site Plan

February 3, 2000

FIGURE 2

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creates the primary feature of the property, a stream valley withsteep sides and a series of six ponds. The diversity of wildlifeinhabiting Winterthur is relatively high including a number ofspecies of special concern, those that are rare or uncommon and/orthreatened within the state.

Winterthur is committed to being a good steward of the land andto fostering a greater understanding and appreciation of ourenvironment. As a result of that commitment, in October 1996,Natural Lands Trust, along with Patricia Ann Quigley, Inc. andHyla Associates, was engaged to prepare an EnvironmentalManagement Study for the property. The purpose of the study isto develop and implement a stewardship plan which will assurethat future management, events, and site development will beconducted in an environmentally responsible manner.Winterthur’s short term goal for the study is to inventory theenvironmental resources and review current managementpractices. The long term goals include using the study as aneducational tool, as a baseline for future measurement of thehealth and quality of the environment, and as a guide for futuresite development.

Natural Lands Trust’s approach to the study was to gain athorough understanding of the site, its potential, and currentmanagement practices, capabilities, and problems, and thendevelop a stewardship plan that will serve as a long term guide tothe future use and management of Winterthur. NLT, along withPatricia Ann Quigley, Inc. and Hyla Associates, conducted aninventory of the biological and physical resources of the propertyfrom the fall of 1997 through fall of 1998. Interviews and sitevisits were held with key personnel to review current managementpractices and to obtain their input. Work sessions were also heldwith various staff to discuss existing and potential programmaticuses of Winterthur.

INVENTORY AND ANALYSISBiological ResourcesFloraThe woodland areas at Winterthur are dominated by hardwoodforests, many of which can be classified as old growth (>150 yearsold). Like most of the mature forests in this area the woodlandsoccupy those sites that were inappropriate (too steep or wet) foragriculture. Unlike most of the region’s forests, the woodlands atWinterthur did not suffer major disturbance (clearcutting,hurricane) over the last one and a half centuries. The result was thecreation of a magnificent canopy of large oak, tuliptree, and beech.

The canopy of the woodlands is dominated by native species: oak(Quercus spp.), American beech (Fagus grandifolia), and tuliptree(Liriodendron tulipifera). Native species, primarily American beechand some black gum (Nyssa sylvatica), red maple (Acer rubrum),and hickory (Carya spp.), also dominate the understory. Norwaymaple (Acer platanoides), an introduced invasive species, isbecoming established in the understory of most forested areas andis now the dominant understory species in Browns Woods. Theshrub layer is generally sparse and dominated by viburnums(Viburnum spp.), both native and introduced. Jetbead (Rhodotyposscandens), another introduced invasive species, is becomingestablished in the shrub layer. The herbaceous layer throughoutmost of the woodlands is sparse.

These woodlands show signs of the degradation which plagues thisregion’s forests. Invasive vegetation, including species from theformal gardens, are well established in the understory.

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Regeneration of native tree, shrub and herbaceous species arespotty at best, a result of both competition from exotic vegetationand consumption by white-tailed deer. This raises serious concernfor the perpetuation of the existing woodlands.

Hedgerows function as corridors for wildlife to move betweenwoodland patches. Unfortunately, with the introduction ofinvasive plants, they have become ideal edge habitat for theproliferation of these species. Invasive vines such as Japanesehoneysuckle, Oriental bittersweet, and grape thrive alonghedgerows and woodland edges where they receive direct sunlightand physical support from the trees. Invasive shrubs such as theshrub honeysuckles and multiflora rose often join these vines.

The hedgerows at Winterthur are chiefly along roads and therailroad and the impact from invasive vegetation is moderate toheavy throughout. While the canopy trees are mostly native, theyare experiencing the same lack of native tree, shrub and herbaceousspecies regeneration as the woodlands.

Meadows (including wet/riparian areas) are the dominantvegetation type at Winterthur. The dominant species in themeadows is the native grass broom-sedge (Andropogon virginicus).Most of the meadows contain a high degree of native herbaceousvegetation, due primarily to the regular mowing schedule. Theupland meadows are presently in hay production, with either oneor two cuttings each year, and the wet meadows are not hayed butare rotary mowed annually. Some areas, especially those now beingallowed to succeed to woodlands, are moderately to severelyimpacted with invasive species.

FaunaField surveys of amphibians, reptiles, birds, mammals, butterflies,dragonflies, and damselflies were conducted on foot, aided by theuse of binoculars and spotting scope. Species were identified byvisual observation, sound (e.g., frog and bird calls), and signs (e.g.,tracks). In addition, live traps (have-a heart and Sherman) wereused to capture small mammals and hand nets were used tocapture dragonflies. Species of “special concern,” those designatedby the Delaware Natural Heritage Program as being of 1st, 2nd, or3rd priority ranking for protection out of 5 ranking categories,were noted.

Overall, the diversity of fauna at Winterthur is good, especially inthe woodlands where it appears relatively high. Species of specialconcern that were observed on the property include:

Amphibians and Reptiles - Northern Red Salamander andQueen Snake

Birds - Great Blue Heron, Great Egret, Black Vulture, Osprey,Bald Eagle, Northern Harrier, Cooper’s Hawk, Broad-wingedHawk, American Kestrel, Herring Gull, Common Nighthawk,Hairy Woodpecker, Pileated Woodpecker, White-breastedNuthatch, Brown Creeper, Veery, Warbling Vireo, NorthernParula, Chestnut-sided Warbler, Black-and-white Warbler,American Redstart, Kentucky Warbler, Hooded Warbler,Yellow-breasted Chat, Chipping Sparrow, and EasternMeadowlark

Mammals - Red Bat and Red Squirrel

One uncommon species, the Appalachian Azure butterfly, wasfound to be fairly common in the Azalea Woods portion of theGardens Area. Although not listed by the Delaware Natural

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Heritage Program as a species of special concern, the AppalachianAzure has only been found in one other location in Delaware.Several larvae were found on their host plant, black cohosh.

Aquatic ResourcesAquatic resources within Winterthur consist of streams, ponds,and wetlands. The property almost fully includes Clenny/WilsonRun, a first to second order tributary of the Brandywine Creek.The segment of the stream that flows through the Winterthurgrounds (northwest of Routes 92 and 100) is designated by theState of Delaware Surface Water Quality Standards (February 26,1993) as “ERES” or waters of exceptional recreational orecological significance. The watershed is part of the highly valuedBrandywine Creek system and is largely undeveloped except forthe Winterthur property, several golf courses and low densityresidential development.

The original hydrology within the property has been alteredthrough dam and stream channel construction, the capping ordiversion of natural seeps and springs, the deposition oflandscaping waste and rubble into wetlands, and the mowing ofstream buffers. The latter has created ideal habitat for Canadageese which further degrade water quality.

Overall, Clenny/Wilson Run supports a moderate diversity ofpiedmont stream fish. Kick net samples of macroinvertebrateswere obtained at five locations along Clenny/Wilson Run, one ofwhich is just downstream of Winterthur in Brandywine CreekState Park. Three of these correspond with established DelawareDepartment of Natural Resources and Control (DNREC) waterquality sampling stations. The stations within the property rangedfrom man-made stream habitat with very poor water quality tonatural stream habitat with fair water quality. The downstream off-

site station presented good macroinvertebrate habitat withexcellent water quality.

All of the twelve relatively small ponds at Winterthur maintainpopulations of fish. Grab samples of pond water were obtained atthe outflow structures of six ponds: Armour Farm Pond, 11th TeePond, Upper Pavilion Drive Pond, Lower Duck Pond, East BarnPond, and the Routes 100/92 Pond.

Total suspended solids, which relate to turbidity, were below the10 mg/l detection limit in all ponds except East Barn Pond whichdisplayed 12.0 mg/l. Dissolved oxygen levels were generallyfavorable except for Armour Farm Pond. pH levels, a measure ofaqueous acidity and basicity, were generally favorable except forthe 11th Tee and Routes 100/92 Ponds which had slightly elevated(more basic) values. Phosphorus is an important nutrient for plantgrowth, but excessive levels can cause increased algal ormacrophyte growth leading to pond eutrophication. Totalphosphorus levels were favorable except for East Barn Pond whichslightly exceeded the recommended value. Total coliform is ameasurement of certain bacteria which are associated with sewage(certain levels of which are always present in healthy aquaticsystems). The highest total coliform values occurred withinArmour Farm Pond, Lower Duck Pond, East Barn Pond, and theRoutes 100/92 Pond. Coliform inputs to the ponds do occurnaturally and wide variation in total coliform values is common.However, excessive loadings are occurring through the droppingsof resident Canada Geese and probably from off-site septicsystems. Chlorophyll a, a plant pigment which converts lightenergy to chemical energy during photosynthesis, indirectlymeasures growth, primary productivity, and algal abundance orstanding crop. Only the 11th Tee Pond exceeded the level for ahealthy non-eutrophic lake or pond.

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Due to the large study area, a full-scale point-to-point survey of allregulatory wetlands on the Winterthur grounds was notrecommended. To meet the goals of an overall land stewardshipplan, it is essential though to have preliminary boundaryidentification, based on field observations, with detailedobservations recorded of the wetland type, dominant species, rareor endangered species, and degree of disturbance. Full-scalesurveying of wetland boundaries should be reserved for key areaswhere potential future facilities development or expansion isconsidered which may encroach on regulated wetlands.

A diversity of wetland types — swamps, marshes, and ponds —are found at Winterthur. These wetlands occur in association withseeps, streams, and impoundments located in the watershed ofClenny/Wilson Run which drains eastward to Brandywine Creek.Forested wetlands occur where a canopy has remained and wetmeadows occur in areas that are periodically mowed. Extensivemanipulation of the ground and surface water resources atWinterthur have effected the wetlands. Piping has depleted waterfrom some areas causing wetlands to diminish in area over timewhile elsewhere, wetter circumstances have been created.Winterthur as a whole has an abundance of water which supportsan array of relatively natural wetlands as well as the many lovely,yet unnatural, ponds.

Physical Resources and FeaturesGeologyWinterthur lies almost completely within the WissahickonFormation, the dominant rock type in the northwestern geologicPiedmont Province in Delaware. This province, whose name

literally means lying at the base or the foot of the mountains, iscommonly referred to as “Delaware’s hard rock country.”

The Wissahickon Formation may be greater than 8,000 feet thickand is less resistant to chemical and physical weathering. Thus,deeply incised stream valleys and steep slopes characterize thisportion of the basin. Amphibolites and gneisses support ridgeswhile mica schists erode to form deep-sided valleys. The formationhas considerable secondary porosity and therefore has capacity tostore and transmit groundwater. Although high densities of jointsand faults exist in some locations and may be able to supportinitial groundwater yields of 300 to 400 gallons per minute,groundwater typically yields 10 gallons per minute.

SoilsWinterthur lies with the Glenelg–Manor–Chester soil association.This association is in one large area in the northern andnorthwestern parts of the county. It consists mainly of gentlysloping to moderately sloping soils. On the bottomlands andcrests, however, the soils are nearly level, and in some areas abovestreams they are steep. The major soils in this association are deep,well drained, and micaceous and provide good building sites,though slope is a limitation in places. In most places excavation isnot difficult and is not limited by wetness. The soils generally haveonly slight to moderate limitations to use for sewage disposal byseptic tanks.

Topography and SlopesWinterthur’s topography is very typical of the character of theunderlying Wissahickon Formation — deeply incised streamvalleys with steep slopes. The primary feature is the main Clenny/Wilson Run valley running roughly west to east. The ridges to the

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north and south of the stream have gentle, 0–8%, slopes on theirtops with the side walls typically over 15% with large areas over25%. The highest elevation is approximately 432 feet, occurring inthe northwestern corner of Bidermann Golf Course near theintersection of Center Meeting and Pyles Ford Roads. The lowestelevation, approximately 218 feet, occurs just below the Routes100/92 Pond for an overall difference of 214 feet.

Existing Land UseMeadows..................................... ± 468 ac. 48% of total area

Woodlands and hedgerows .......... ± 192 ac. 20%

Golf course ................................. ± 150 ac. 16%

Gardens, incl. Pavilion Pine Grove .... ± 52 ac. 5%

Ponds ............................................ ± 11 ac. 1%

All other areas ............................... ± 93 ac. 10%

Total .......................................... ± 966 ac.

Streams ............................... 28,000+ lf / 5.0+ miles

Railroad ................................ 3,500+ lf / 0.5+ miles

Roads ................................ 75,500+ lf / 14.0+ miles(±80% are “improved”)

PROGRAMMATIC USESCurrent Uses and EventsGeneral admission to Winterthur includes access to the “GardenArea Proper.” Maps are available for self-guided walking tours.Also included with the general admission is a 30–45 minutenarrated tram ride through the garden and outlying areas ofWinterthur. Topics covered include the history of the property andthe story of Henry Francis du Pont, as well as aspects of nature,color, and seasonal interests. Guided garden walks are also offered.

Programs offered by the Garden Department have included gardenlectures, horticultural and design symposiums featuring nationaland international experts and speakers, and the “SuccessfulGardener Series,” a series of hands-on workshops for the homegardener.

Special events have included “Picnicking Under the CherryBlossoms,” “Easter in the Garden,” a family event, a “PlantExtravaganza” with experts available to answer questions, talks,guided garden walks, and plants and books available for purchase,and the annual Point-to-Point Races and Craft Festival. The Point-to-Point Races are held on the first Sunday in May each year with20,000 to 24,000 people attending typically. The Craft Festival,which will have its fourth year in 1999, is a 2-day event over theLabor Day weekend with 180 juried craftsmen that attracts over20,000 people.

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Future Uses and EventsGardens, Programs, and Special EventsThe following recommendations for additional or expandedprogrammatic uses related to environmental issues and concernshave been generated as a result of this study and from internalwork sessions of the Winterthur staff.

~ Highlighting native plants throughout the garden

~ Special subject tours including “Birds in the Garden,” “NativePlants in the Garden,” “The Winterthur Estate/Farm,” and“Winterthur’s Natural Areas”

~ Lectures and/or walks on subjects such as birdwatching andfungi identification

~ Workshops on natural areas management and restorationtechniques

~ Arbor Day events highlighting native species

~ Azalea Festival events highlighting native species

TrailsThe opportunity exists to utilize the natural areas to greatlyenhance the recreational and educational experience of Winterthurvisitors. A well defined trail system with interpretive materials(brochures, signage) could be used to tell a more complete story ofthe property, inform visitors of proper management techniques,and provide inspirational views of meadow vistas and the largetrees of the woodlands. A potential trail system, divided into threephases, has been proposed for the Winterthur property. The

phasing is to allow Winterthur to experiment with increasedpublic use of the natural areas and to evaluate the programthroughout its implementation.

Research and EducationThe natural areas at Winterthur offer a wide range of research andeducational opportunities through which Winterthur, local naturalresource managers, and local schools and universities can benefit.Winterthur staff and other resource managers will benefit byreceiving information that can assist them in better understandingand managing their natural areas. The academic world gains byhaving access to relatively secure natural areas with diverse plantcommunities. In addition, supporting environmental educationhelps to educate the next generation to the importance ofstewardship.

There are three resource management issues associated withresearch and education programs. The first is the concern forbalancing public use policy with the need to protect research andinterpretive sites from unintentional damage from property users(hikers) and vandals. Before promoting or increasing passiverecreation, it must be ascertained how this will impact current orfuture research and education activities. The second concern is thepotential impact on staff resources that would accompany theseactivities. While Winterthur has no plans to conduct research oreducational projects itself at this point, there will be a need tocoordinate and monitor the activities. Increases in staff demandscould result in a reduced management level or lost research oreducational opportunities. Finally, consideration should be givento possible conflicts with other existing programs such asagricultural leases and deer management.

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Conservation EasementsA conservation easement is a legal agreement between a landownerand a conservation organization or government agency thatprotects land while leaving it in private ownership. The restrictionsof the easement, tailored to suit the particular property andlandowner’s goals, permanently limit a property’s uses in order toprotect its conservation values. The easement binds all present andfuture owners of the eased land. A landowner generally donates theeasement to a qualified conservation organization or governmentagency, which in turn ensures that the conditions of the easementare met over time.

Conveying a conservation easement is a way of making a tangiblecommitment to the preservation of the natural resources, culturalheritage, scenic beauty, and open spaces of a property, and thecommunity in which it lies, for present and future generations.Winterthur is a significant property not only for its size, almost1,000 acres of which 90% is open, but also for the diversity andhealth of the natural habitats that occur there. Over time, theselands will become more and more important as developmentpressures increase and open space and natural areas are lost. Theproperty could also provide valuable information to local resourceprofessionals trying to understand current ecological problems andto prepare for future ones.

The Board of Trustees for Winterthur has already begun to addressthese issues. The Policy and Guidelines for the Gardens and Grounds,May 1987, states that “Winterthur is committed to conserving theformer estate and residence of Henry Francis du Pont.” The Boardalso authorized this Study, which has a goal of developing andimplementing a stewardship plan to assure that futuremanagement, events, and site development will be conducted in

an environmentally responsible manner. The logical next step inensuring this commitment into the future would be for theWinterthur Board of Trustees to consider conveying aconservation easement.

Future Site DevelopmentThe first step in identifying suitable areas for future sitedevelopment is to identify areas which should not be developed.These “preservation areas” contain critical constraining naturalfeatures such as wetlands, hydric soils, and steep slopes whichmake them unbuildable. The next step is to identify “conservationareas” where development could occur, but in a limited manner;areas with fewer development constraints but important naturalfeatures. These include features that are still environmentallysensitive, such as soils with a seasonally high water table, moderateslopes, woodlands, and scenic viewsheds, but vary in importance,vulnerability, or fragility. What remains are the areas most suitedfor development, the “potential development areas.”

The Future Site Development plan shows such an analysis ofWinterthur. What this mapping does not include though, is scenicviewsheds. The determination of these are very site specific andinvolve many factors such as historical and cultural significance,botanical interest, and garden design which are outside the scopeof this Study. Winterthur staff will need to overlay thisinformation during the planning process for any future sitedevelopment.

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LAND STEWARDSHIPWinterthur’s natural landscape offers an excellent representation ofregional physiographic characteristics. Its balance of woodland,meadow, and stream habitats supports a diverse assortment ofplant and wildlife species and beautifully compliments the formalhorticultural areas. Like the Garden, these natural areas offer aunique menu of management challenges and opportunities.Successfully addressing the challenges and opportunities withinsuch an important natural areas will require a serious, on-goingcommitment to stewardship based upon a long-term perspective ofprotecting and enhancing the natural communities and theirenvironmental and ecological benefits.

All stewardship programs should be based upon the conservationpriorities of the site. Conservation priorities can be ecological,recreational, historical, or programmatic depending on the contextof the site within the local landscape, legal restrictions, thehistorical use of the property, and the goals of the landowner.Based upon Winterthur’s goals and the existing natural resourceswithin and around Winterthur, we recommend establishing thefollowing conservation priorities to guide the management of thenatural areas:

ECOLOGICAL: Water resources of the Clenny/WilsonRun watershed

Habitat for local wildlife

Rare and endangered species

HISTORICAL: Open landscape resulting from the designintent of Henry Francis du PontLandscape design, including scenic viewsfrom the Garden

PROGRAMMATIC: Environmental education for visitors

RECREATIONAL: Natural environment for visitors and staff

BUDGETARY: Human resources

Financial resources

Once conservation priorities are established, a stewardship plan isdeveloped to minimize the internal and external threats to thesepriorities with the further goal of enhancement.

This chapter provides guidelines on which to develop a detailedstewardship plan. It includes sections on woodlands andhedgerows, meadows, and aquatic resources that outline generalrecommendations for resource types, give specificrecommendations for management units, and provide stewardshipguidelines for achieving the recommendations. The stewardshipguidelines include sections on vegetation management/restoration,wildlife management, stormwater management, and aesthetics/hazards. These are based upon the current health of each resource,a review of current management practices, and the goal to protectand enhance the conservation priorities listed above. There are alsosections on trail design and maintenance, staffing and equipment,and priorities.

The recommendations offered within this report are based uponcurrent information and technology and land managementexperience within other natural areas. These recommendationsshould not be implemented with blind faith in perpetuity. Becauseof the uniqueness of every property and the fact that we aredealing with evolving natural systems, the management regimeshould similarly evolve over time as new “bad actors” areidentified, land management knowledge and technology change,

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and Winterthur’s goals are modified. Land stewards need to beaware of both the ubiquitous and site-specific natural processesinvolved and the potential of existing management techniques, butcreative in applying each technique to (and developing new onesfor) individual natural areas.

Woodlands and HedgerowsThe woodlands at Winterthur were actively managed until themid-1950s to produce lumber for in-house use. The currentmanagement goal is to maintain them in as natural a state aspossible. Aesthetics and hazards are the main concerns, particularlyin the areas that receive more public use or scrutiny. Managementin all other areas is largely done on an as-needed basis to removedown or hazardous trees and any obstructions to the internalroads. The control of invasive vegetation has not been amanagement priority.

Given the conservation priorities and the current goals ofWinterthur, there needs to be a significant increase inmanagement of the woodland resources. Because of their manyenvironmental, ecological, and human benefits every attemptshould be made to sustain the woodlands on the property. Todaythere are serious threats to that goal. Addressing those issues andfacilitating additional public use will require an increasedcommitment of staff resources.

The perpetuation of any woodland community depends upon theongoing establishment of tree and shrub regeneration that aresufficient in number to occupy the gaps that are created by naturalor human disturbance to the various structural layers (canopy,understory, shrub) within these plant communities. Throughoutthe woodlands and hedgerows of Winterthur there is a clear

deficiency of native tree and shrub regeneration. Given the age ofthe canopy trees and their increased susceptibility to windthrow,this lack of regeneration raises concerns for the perpetuation of allthe existing woodlands and the loss of the genetic material thatcreated these impressive communities. The presence of invasivevegetation further decreases the probability that the future woodedareas of Winterthur will come close to resembling the currentwoodlands.

The lack of tree and shrub regeneration results principally fromcompetition with invasive vegetation for growing space and anoverabundance of white-tailed deer. In order to perpetuate theexisting woodlands it will be necessary to aggressively address theseproblems as soon as possible. If allowed to reach a crisis level, thetask of restoration will become formidable. More importantly,valuable ecological and human benefits will be lost for manydecades.

General Recommendations~ Control invasive vegetation through physical removal, chemical

application, and the reduction of forest edge.

~ Expand woodland areas to protect water resources, reduce edge,and create wildlife corridors between woodland parcels byreleasing designated meadow areas to succession.

~ Eliminate/minimize the practice of removing dead and dyingtrees.

~ Reduce deer impact through increased harvest levels andprotective devices (fencing, tree shelters).

~ Establish 10 x 10 meter exclosures in several woodlands formonitoring and interpreting the deer impact on woodlandvegetation.

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~ Improve aesthetics/eliminate hazards by cleaning up scatteredtrash, removing obsolete structures (with no historical,interpretive, or functional value) and materials, andconsolidating needed materials (woodchips, soil) in leastconspicuous area(s).

~ Address stormwater erosion areas through maintenance andmodification of man-made structures and stabilization of terrainand natural streams.

MeadowsHistorically, meadows occurred as breaks in the eastern deciduousforest resulting from human and natural disturbances such asclearing for agriculture by native Americans, fire, periodicflooding, insect infestation, and soil conditions (saturated,serpentine) that restricted growth of woody plants. Mostmeadows, therefore, existed as temporary ecosystems. Withoutfurther human or natural disturbance, natural succession wouldreturn a meadow to native woodland conditions within 50 to 100years.

The meadows at Winterthur, like those throughout the East, arethe result of the rise and fall of agriculture following Europeansettlement. During the next three centuries all but the mostrestrictive (wet, steep) lands were cleared to raise crops for thegrowing eastern cities. As the agricultural center of the countrymoved south and west during the 20th century, and, morerecently, development pressure has increased, much open land(particularly that on marginal soils) has reverted to woodlands orhas been converted to housing developments.

The historic agricultural landscape remains at Winterthur bymaintaining the open areas as meadows. Indeed, meadows

currently make up almost 50% of the property and total almost470 acres. This unusually large meadow resource provides not onlybeautiful vistas from the Gardens but significant ecologicalbenefits. Currently the meadows are maintained through a leaseagreement with a local farmer who takes two cuttings ofmushroom hay each year. Modifying the current managementregime could significantly increase the ecological benefits withoutimpacting the Garden vistas.

In general, the meadows are in very good condition compared tomost meadows in this region. They are relatively free of invasivesand are dominated by native warm-season grasses, particularlybroomsedge. Warm-season grasses are desirable because they arepreferred as nesting and feeding sites for native animals, includinggrassland nesting birds. Many of these birds, such as bobolink,Eastern meadowlark, grasshopper sparrow, savannah sparrow,upland sandpiper and bobwhite quail, have declined drastically inrecent years due to the loss of habitat from development andchanges in farming practices, including earlier mowing times andthe extensive use of non-native cool-season grasses for turf andhay.

General Recommendations~ Delay the timing of haying from early June to the beginning of

July to improve habitat for grassland nesting birds (e.g. EasternMeadow Lark, Grasshopper Sparrow, Field Sparrow, andpossibly Bobolink) by allowing adequate time for successfulnesting and rearing of young.

~ Harvest only one crop of hay per year instead of two or harvesthay in designated fields on a rotating schedule, cutting eachfield every other year. This will create tall grass areas in winterthat provide winter habitat for grassland birds.

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~ Create successional habitats by removing designated meadowsfrom mowing to favor old field dependent species.

~ Install artificial bird nest boxes for species such as EasternBluebird and American Kestrel.

~ Develop and maintain a trail system through the upland fieldsand the restoration areas to allow for routine maintenance,nature study, and passive recreation.

~ Gradually increase the diversity of meadows by planting plugsor overseeding several additional native species including Indiangrass, switchgrass, big bluestem and little bluestem.

Aquatic ResourcesAccording to the Delaware Department of Natural Resources andEnvironmental Control (DNREC), water quality concerns inClenny/Wilson Run on the Winterthur grounds include periodicalgal blooms that occur in the many ponds and which are oftentransported downstream during storms. In addition, the large andincreasing number of Canada geese using the ponds and mowedfields contributes significant nutrient and fecal coliform loading tothe aquatic system resulting in eutrophic conditions in the pondsand periodic release of nutrient-rich waters to the Brandywinesystem. Other concerns noted by DNREC include the lack ofriparian buffer or natural edge around the Winterthur ponds andcreek edge.

It is clear that although still relatively healthy, the aquatic resources(ponds and stream complex) through the Winterthur portion ofthe watershed are being stressed and are in danger of becomingpermanently degraded if measures are not taken to better managethe lands surrounding them.

General Recommendations~ Provide more riparian buffers. Establish at least tall grass

meadow buffers (preferably shrub and/or tree buffers whereappropriate) along all streams and ponds. Establish or expandwoodland buffers where they do not impact importantviewsheds.

~ Address stormwater erosion areas through maintenance andmodification of manmade structures and stabilization of terrainand natural streams.

~ Control invasive vegetation (particularly exotic vines) whichprevents natural regeneration or planted trees and shrubs frombecoming established. Monitor and control invasives(phragmites, knotweed) which displace native wetland species.

~ Install nest boxes for Wood Ducks and Eastern Screech Owlsand basking logs for turtles. Establishing riparian buffers shoulddiscourage Canada Geese.

~ Remove cement lining from stream areas and re-establish a morenatural, meandering stream channel using bioengineeringtechniques.

Trail Design and MaintenanceThis section provides guidelines for new and existing trails that fallinto three types: recreation enhancement, environmentalprotection, and public use and safety. Specific guidelines andrecommendations are provided for trail construction, trailmarking, and trail signage.

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Staffing and EquipmentStaffingThe natural areas encompass over 70% of the land area atWinterthur, yet there is no personnel dedicated exclusively to theirmanagement. Currently, management within these areas is doneon an as-needed basis by members of the HorticulturalDepartment as part of their job responsibilities that focus onmaintenance of the hardscape (roads, bridges, garden structures)within the Garden and setting up for the Point-to-Point and CraftFair. While this has served to handle urgent maintenance needs,such as removal of hazardous trees, it has fallen far short inprotecting these areas from natural and human degradation. Toseriously address existing problems and to realize potentialopportunities highlighted within this plan, a greater commitmentof staff time will be needed for the management of Winterthur’snatural areas.

It is recommended that Winterthur dedicate one staff member tofocus exclusively on the management of the natural areas. Thisperson should have an educational background and hands-onexperience in natural resource management and environmentaleducation. Responsibilities would include (1) to prioritize andorganize restoration and enhancement projects, (2) to coordinatewith other staff for time and equipment, (3) to monitor ongoingprojects, and (4) to develop and implement an environmentaleducation program to compliment the tours of the formal gardens.This person would also provide a natural resource perspective toreview activities proposed by other departments that might impactthe natural areas.

EquipmentThe staff at Winterthur appears to be well-equipped to effectivelyhandle management needs within the natural areas. Mostmaintenance and restoration work within the woodlands can beaccomplished with small hand tools, a small chainsaw, and ahandheld or backpack herbicide applicator. The only specializedequipment would be that needed for meadow restoration andmaintenance.

PrioritiesThis report offers numerous recommendations for the restorationand management of the extensive natural areas of Winterthur.Given the many other on-site priorities of the management staffthere is currently insufficient time to address all of theserecommendations. Therefore, the first priority Winterthurshould consider is the dedication of one staff member (orequivalent) to focus exclusively on the management of thenatural areas. This person would oversee and coordinate thenecessary restoration and enhancement projects, monitor ongoingprojects, and oversee and coordinate public use and research andenvironmental education programs.

To assist Winterthur in making the most efficient and effective useof the time and resources available, we are providing a list ofoverall priorities for work within the natural areas. Initiating thesewill have the greatest environmental and ecological benefits withthe least investment of staff resources. These priorities are basedupon current conditions and should be reviewed on a periodicbasis as conditions and internal priorities change.

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~ Reduce the local deer populationContinue efforts to lower the population toencourage native tree and shrub regeneration andprotect woodland wildflowers.

~ Modify the meadow mowing scheduleMow only once per year after July 15th and considermowing only half of the meadows each year toprovide better habitat for grassland dependent fauna,particularly birds.

~ Cut invasive vines on canopy treesProtect the existing canopy to help shade invasivesand provide a native seed source.

~ Address stormwater runoffReducing the rate of flow from the main parking lotand from the golf courses will protect on-site soilresources and water resources within and outside ofWinterthur.

~ Reduce ornamental groundcoversEradicate or at least control patches of invasive exoticgroundcovers in order to maintain and/or restore thenative herbaceous vegetation.

~ Cut understory invasive trees and shrubsRemoving these trees will allow more light topenetrate to the forest floor and encourage treeregeneration. It will also reduce the invasive seedsource.

~ Riparian bufferEstablish at least tall grass meadow riparian buffers(preferably shrub and/or tree buffers whereappropriate) along all streams and ponds to improvewater quality.

~ Promote research and educationContact local schools and universities and offer thesite for appropriate research and education projects.Students and researchers will benefit by havingdiverse and relatively secure sites and propertymanagers will benefit with an increasedunderstanding of the on-site resources.

~ Establish public trail systemCreating an interpretive trail system (starting withPhase I) will provide visitors a contrasting experienceto the formal gardens and perhaps garner support forneeded management.

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