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Plant Collections Policy

Policy Objective

The objective of the collection policy is to continue the development and management of  the plant collection at Longwood Gardens. This policy enables the staff to support the mission of Longwood Gardens through responsible and appropriate collection acquisition, management, display, and distribution while upholding the highest professional standards.


The plant collection policy is approved by the Board of Trustees of Longwood Gardens. Responsibility for implementation of this policy lies with the Director. This policy is reviewed every five years and revised as needed. Responsibility for the review and revisions of this policy resides with the Curator of Plants and the Plant Collections Committee, members of which will represent all stake-holders across the entire organization.


Longwood Gardens’ plant collection consists of all accessioned plants, i.e., plants assigned an accession number and registered in the plant records system. Historically, the size of the plant collection at Longwood Gardens has varied between 3 and 13 thousand taxa, comprising plants of horticultural interest.

Core collections

Certain collections of the highest priority at Longwood Gardens are designated as core collections, which receive special focus with regard to their development, management and display in the garden. Core collections are central to the mission of Longwood Gardens. Each core collection has a plan for its development, management and display, devised and periodically reviewed.

Native and naturalized alien plants

Native and naturalized alien plants occurring spontaneously at Longwood Gardens are considered part of the Gardens’ plant collection. They make up a variety of plant communities existing at Longwood Gardens, such as forests, meadows, wetlands, and fields, which play a vital role in supporting ecological functions of the Gardens’ environment. The native and naturalized alien plants fulfill display, environmental, education, and research functions. For naturalized alien plants which have become invasive see Section 15. Invasive plants.

Plant genetic resources

Longwood Gardens adheres to the provisions of the Convention on Biological Diversity in all of its plant acquisition, usage and distribution activities and endorses the Principles on Access to Genetic Resources and Benefit-sharing for Participating Institutions. These provisions and principles are applied to all plant genetic resources acquired from in situ and ex situ sources after 1993. These plant genetic resources for the purpose of this policy are referred to as CBD Material. Projects involving the CBD Material will adhere to the terms of comprehensive Access and Benefit-Sharing Agreements between Longwood Gardens and collaborating parties.

Collection access

Longwood Gardens provides access for the purpose of viewing its plant collection in the public areas during regular visiting hours. Plants that are not in public areas may be accessed subject to special arrangements made with Longwood Gardens.


Plants may be acquired for the collection through legal means in accordance with all applicable regulations including the United States Department of Agriculture – Animal and Plant Health Inspection Service (APHIS) plant import requirements, the Convention on International Trade in Endangered Species (CITIES), the Endangered Species Act (ESA), the Lacey Act, and  the Pennsylvania Plant Pest Act (PPPA). Longwood Gardens assures that its staff is properly trained and annually updated on the applicable regulations.

 Plants that are considered to be CBD Material may be acquired pending signing the Material Transfer Agreement by both Longwood Gardens and the provider. In cases where provider does not advance his or her own agreement, Longwood Gardens’ Material Transfer Agreement may be used (see Appendix I) as a template.

Longwood Gardens staff, involved in plant acquisition, are expected to adhere to the high ethical standards described in Longwood Gardens’ Employee Policy Manual. In addition, Longwood Gardens acquires plants through collaborations only with the individuals and organizations which share Longwood’s values and high ethical standards.

Acquisition approaches include purchase, donation, and collections from in situ populations. Only plants advancing one or several of the collection functions can be acquired. The purpose of all plant acquisitions, i.e., their immediate or potential function at Longwood Gardens, must be stated before these plants can be accessioned.

All plants acquired for Longwood Gardens are subject to health inspection conducted by qualified staff in accordance with Plant Health Division reception protocol.

Proprietary germplasm

Longwood Gardens develops original and unique germplasm through its breeding and selection program. Plants which are part of this program and have been raised at Longwood Gardens are considered property of this organization. Access to the information on such plants in the plant records system is made available only to Longwood Gardens’ staff. Horticultural selections resulting from the breeding and selection program are approved and named by the Intellectual Capital Steering Committee. When appropriate, this committee will recommend that Longwood Gardens applies for legal protection of its proprietary rights for these new selections, through such means as a United States Plant Patent or Plant Breeders Rights.


Longwood Gardens is committed to maintaining comprehensive records on all plants in the collection. Plant records procedures are set up to acquire, organize, and preserve accurate, complete, and current information on all plants in the collection. Proper record-keeping requires input and participation from all staff members who are generating or utilizing information on plants in the collection. The Curator of Plants oversees the plant records system, while the Plant Records Manager is responsible for its operations.


Longwood Gardens maintains a herbarium as a means to document its living plant collection. Herbarium specimens are indispensable in the process of verification of the identity of plants in the collection and in carrying out taxonomical research. As a whole, the herbarium preserves the history of Longwood’s living collection for future generations. It also presents a unique value to Longwood Gardens’ educational programs by providing instructional material. The herbarium collection serves not only the needs of Longwood Gardens but also of the scientific community at large. Of special significance are specimens of horticultural selections cultivated in the United States and specimens of plants introduced into cultivation through Longwood Gardens’ plant exploration program.


Longwood Gardens considers plant distribution as an important means of fulfilling its role as a supportive member of the horticultural community. Plants covered by the Convention on Biological Diversity or by other agreements or patents limiting their use can be shared only when permission can be secured from relevant stakeholders or patent holders in the country of origin. Plants which are part of Longwood Gardens’ breeding and selection program can be made available for testing to collaborating parties pending approval from the Research Steering Committee. Other plants can be sold to the public or freely distributed. Longwood Gardens keeps a current Pennsylvania Department of Agriculture Bureau of Plant Industry Nursery/Greenhouse – Nursery Dealer Certificate in compliance with Pennsylvania Plant Pest Act as it applies to plant sales. For plants that are freely distributed, three programs – Special Plant Distribution, Plant Request, and Commercial Release – are in place.


Plants that have died or living plants that no longer fulfill any of the functions of the collection are to be deaccessioned. Living plants can be deaccessioned pending approval of the Division Leader in charge of a given area. Deaccessioning of living plants fulfilling functions other than display requires additional consultation with the following staff:  the Curator of Plants for the historic and germplasm preservation functions; the Education Department Head for the educational function; the Research and Production Leader for the research function; and the Plant Health Division Leader for the environmental function.

Deaccessioned living plants not covered by any stipulations limiting their distribution may be given to Longwood staff, volunteers, or students for their personal use pending approval of the Division Leader in charge, or to organizations or individuals outside Longwood Gardens through the Plant Request program pending approval of the Curator of Plants. Deaccessioned living plants covered by restrictions on their distribution are to be destroyed (see Section 13. Distribution).

Invasive plants

Longwood Gardens is committed to making every reasonable effort to eliminate or minimize populations of invasive alien plants occurring in the gardens and in the surrounding areas, and to prevent introduction of new invasive species by following the principles of the St. Louis Declaration and the Voluntary Codes of Conduct for Botanical Gardens and Arboreta. Invasive alien plants, as addressed by this policy, are those that are not indigenous to the mid-Atlantic region, have spread to natural areas, and have established reproducing populations. All plants on state and federal lists of invasive species are included. Common agricultural weeds are excluded.