More than 12,000 labeled plants of approximately 2,500 types are growing in the Arboretum’s living collection. These include representatives of the temperate floras of North America, Asia, and Europe. This historic collection traces its foundation to John Morris’s interest in plants from around the world, and includes plants collected in China by E.H. Wilson at the turn of the century. Many of the Delaware Valley’s "trees-of-record" (the largest of their kind) are found in the Arboretum. Most notable are the katsura, Engler beech, Bender oak, and trident maple. Click here for a tour of our great trees, accompanied by photographs and descriptions.
Staff members have regularly engaged in plant collecting expeditions in Asia and the United States, increasing the diversity of plants available for today’s urban and community landscapes. Currently plants from 34 countries are represented in the collection with a primary focus on Asian temperate species. Significant plant groups in the Arboretum’s collection include maples, magnolia species, native azaleas, members of the witch hazel family, roses, hollies, and conifers.
Please note, visitors are not allowed to climb or sit on the limbs of trees. The Arboretum is home to a number of champion trees, some of which are very old. With 130,000 visitors annually, climbing becomes a safety issue for both children and the trees. We don’t want any visitors or trees to break a limb. Thank you!
With the diversity of our collections, there is seasonal interest throughout the year, for all levels of gardeners. Look for the following plants throughout the year:
December through February
Paperbark maple, stewartia, kousa dogwoods, hollies, and rare and unusual conifers of all shapes, sizes and colors.
March through June
Witchazels, winterhazels, magnolias, cherries, maples, dogwoods, rhododendrons, azaleas, crabapples, roses, and stewartia.
July through September
Hydrangeas, summersweet, butterfly bush, chaste tree, sourwood, golden-rain tree, and annual and perennial displays.
September through November
Maples, black gum, sweet gum, dogwoods, oaks and many other colorful trees.
A catalogue of plants in the living collection is available at the front desk of the Widener Visitor Center. All of the plants in the Arboretum are labeled and mapped, and this catalogue can lead you to plants in which you have an interest.
Enhance your Arboretum experience, either onsite or when planning a visit:
Arboretum Adventure, this family activity explores the grounds and shares plant science lessons along the way.
Collection Connection, search the Arboretum’s collection records to locate or learn about favorite plants.
Tours, choose from among a selection of guided pathways through the grounds.
Wi-Fi, connect with the Arboretum, or share photos on social media at hotspots located throughout the garden.