More than 250 varieties of conifers, magnolias, and other cultivars comprise the Arboretum.
When dinosaurs first became numerous in the late Triassic Period, nearly all of the major groups of vascular plants except the angiosperms were in existence. Conifers, cycadophytes, ginkgoes, ferns, and large arborescent horsetails dominated the landscape. By the mid-Jurassic Period, conifers had become more diverse and many of their fossils have been assigned to modern families such as Araucariaceae, Pinaceae and Taxodiaceae.
Angiosperm pollen and leaves first appeared in the fossil record about 140 million years ago in the early Cretaceous Period. By about 90 million years ago, several modern families of flowering plants are represented by good fossil material. These families include the Lauraceae (laurel), Magnoliaceae (magnolia), Platanaceae (sycamore), Buxaceae (box), and Calycantheaceae (sweet shrub).
By the end of the Cretaceous Period, many modern plant families existed with the last dinosaurs, including:
Some unusual species
• Monkey Puzzle Tree
• Hibba Arborvitae
• Alpine Totara
• Lacebark Pine
• Modoc Cypress
• Yezo Spruce
• Southern Magnolia
• Anise Magnolia
• Yulan Magnolia
• Weeping Katsura
• Persian Ironwood
• Fragrant winter-hazel
• Oriental Sweetgum
• Chinese Sweet-shrub
• Coral Beads
• Juglandaeceae (walnuts)
• Cercidiphyllaceae (katsura)
• Berberidaceae (barberry)
• Moraceae (mulberry)
• Fagaceae (beech)
• Ulmaceae (elm)
• Menispermaceae (moonseed)
• Illiciaceae (anise tree)
• Aristolochiaceae (pipe vine)
Our goal is to grow representatives of as many of the Mesozoic Era plants families as we can within our zone 6 site. The initial plantings established a "backbone" of hardy conifers and then the collection was filled out with dwarf and slow-growing conifer cultivars. Currently, there are more than 200 different kinds of conifers in the collection. Recent plantings have focused on trees and shrubs from the Cretaceous angiosperm families. The largest gera collections are pine, juniper, charmaecyparis, arborvitae, and magnolia.
The "Arboretum of Evolution" which began to take form nearly 30 years ago is very young, but is growing into an important asset for the Park and for educators.
A map of the arboretum is available at the park. It identifies the locations of collections and gardens which are listed here.
Within this area of the park there are Douglas firs, Nikko Fir, Nordmann firs, and concolor firs.
The name of these conifers means “tree of life” because some of these conifers can live up to 300 years. Among other plants that form the wall is the Hiba arborvitae (Thujopsis dolabrata ‘Variagata”).
Within this collection are the Lebanon cedar, Deodar Cedars, Blue Atlas Cedars, and the California incensecedar.
“White Mountain’ white pine, Blue Jay, Himalayan pine, Bosnian pine, ‘Pendula’ white pine and a ‘Waterii’ Scots pine grow within this grove near the entrance sidewalk.
East Side Conifers
At this location, the plantings include the Japanese cedar, which is a member of the redwood family, the ‘Oregon Blue” Lawson cypress, a weeping Alaskan cedar, Hinoki false cypress, and a “Chinese fir.”
Among the exposed ledges are plantings of junipers, false cypresses, small arborvitae, dwarf firs, and flowering plants such as lavender and thyme.
Plaza del Sol
Near the entrance to the Exhibit Center are Japanese umbrella pines, recognizable by their plastic-looking foliage.
Plantings in this location include the bald cypress, American sycamores, black gum, willow oak, pawpaws, sweetbay magnolia, Carolina allspice, and a persimmon. Close by is a giant sequoia (Sequoiadendron giganteum) which can grow to 300 feet in its native habitat in California, and a “Hazel Smith” cultivar. Four Dawn Redwoods and a golden larch are also located in this area.
Within this area are Hondo spruce, Oriental spruce, Serbian spruce, and a Black Hills spruce.
East Asian Garden
The rare and unusual species in this planting include the Chinese swamp cypress, a weeping katsura tree, a “kew” ginkgo, and a thicket of yellow-grove bamboo.
London Plane Trees
Lining the entrance drive are hybrids of American and Eurasian sycamores.