University of Tennessee
Forest Resources AgResearch and Education Center
Oak Ridge Forest Cumberland Forest Highland Rim Forest Arboretum

October

There is always something in bloom at the Arboretum! Use our Plants Library to plan a photo shoot or to choose one of the trails to walk. Learn more about the plants at the Arboretum by visiting our Previously Featured Plants list and our Special Seasonal Featured Plants page.


Persimmon (Diospyros virginiana)

Persimmon Tree Persimmon Fruit Persimmon is a moderately sized tree growing to 60 feet in height and 2 feet in diameter. It is the most northern member of the Ebony plant family — other members of the family are tropical or subtropical. A number of Persimmon trees are found along Arboretum Drive and on the edge of the Shade Tree Collection. In September/October, these trees may be loaded with orange fruits that become deep purple as they age.

Persimmon Bark Persimmon Fruit Persimmons are dioecious — meaning that male and female flowers are found on separate trees. The leaves and fruits of the tree are astringent, and have been described as puckery. However, when mature, the fruits lose their astringent tannins and become sweet and delicious. The genus name Diospyros can be translated from the Greek as "food for the gods."

Persimmon is native to the Eastern U.S. — New England to Florida, west to Texas, Iowa, and Kansas. The bark is dark brown to black and is deeply divided into small blocks. The dense wood has been used for such purposes as golf club heads and billiard cues.

Fall Wildflowers 2014

Fall Wildflowers 2014

Pignut Hickory (Carya glabra)

Pignut Hickory Leaves Pignut Hickory Nut Pignut Hickory Bark
Pignut Hickory (Carya glabra) is one of several hickory species found in our Arboretum forests. It is found throughout the Eastern U.S. and north into southern Ontario. It is one of the most common hickories in the Appalachians. The common name was given by early settlers because the abundant nuts provided food for free-ranging hogs. It’s alternate, compound leaves typically have 5 (occasionally 7) glabrous leaflets (i.e., without hairs) that are finely toothed. The pear-shaped to ovoid fruits are about 1" in diameter, with thin husks and nuts that are not ribbed. A distinctive feature of the fruit is that when mature, the husk only splits about half-way along the fruit axis. The bark is relatively tight, has vertically oriented ridges that are rounded, and may be flaky. The nuts, which are high in crude fat and have moderate content of proteins, calcium and phosphorus, are an important food for a variety of mammals, such as squirrels, chipmunks, and black bear, as well as some birds such as turkeys, woodpeckers, pheasants and several songbirds. The strong, hard, tough wood is used for making tool handles, fence posts, sporting goods, agricultural implements, and as fuel wood. Early settlers used thin splits of the wood to make brooms.

Sourwood (Oxydendrum arboreum)

Sourwood in Flower Sourwood Flowers Sourwood is a small to medium-sized tree found along many Arboretum trails. It ranges from Pennsylvania, Ohio, and Indiana, south to northwest Florida, Alabama, Mississippi, and Louisiana. As a member of the Heath Family (Ericaceae), it is related to such plants as blueberries, rhododendrons, and azaleas. The white, bell-shaped flowers are borne in terminal one-sided clusters and appear in late June and July. The fruits mature in late summer and persist on the flower stalks, often into fall and winter. Because the flowers are often near the top of the trees, they may be difficult to see under a forest canopy. The finely toothed leaves, 5-8 in. long, turn a yellow to crimson red in the fall. A good place to observe these trees in bloom is a Sourwood study plot just below the Arboretum’s Elmore Holly Collection.

Sourwood Fall Leaves Sourwood Bark The ridged and often deeply furrowed bark of Sourwood is readily identified especially in older trees where it becomes distinctly blocky. Trees may grow 50-60 ft high, with trunks that are often bent or leaning. The common name comes from the sour taste of the leaves and twigs. Leaves and bark of Sourwood were used by Native Americans and early settlers to treat a variety of ailments such as mouth ulcers, asthma, indigestion, and kidney and bladder ailments. Sourwood has little timber value, but the heavy wood has been used for handles, fuel wood, and specialty items. Sourwood honey is a favorite of many.

Dawn Redwood (Metasequoia glyptostroboides)

Dawn Redwood - Summer Dawn Redwood - Fall Dawn Redwood is a deciduous conifer with flat, needle-like leaves that turn a copper-colored brown in November. A specimen of this tree, planted in 1965, can be seen in the Arboretum’s Central China Collection near the end of Marsh Road. Dawn Redwood is related to Bald Cypress (Taxodium distichum) of the southeastern U.S. and to California’s Redwood (Sequoia sempervirens) and Giant Sequoia (Sequoiadendron giganteum).

Dawn Redwood Leaves In the early 1940s, a Chinese paleobotantist recognized that fossils initially thought to belong to the genus Sequoia, should be reassigned to a new genus, Metasequoia. In 1945, living individuals of Metasequoia glyptostroboides were found in the Sichuan Province of China. Extensive field surveys in the late 1940s found this “living fossil” present in limited populations in both Sichuan Province and neighboring Hubei Province. Propagation of seeds and cuttings at arboreta in the U.S. and elsewhere resulted in Dawn Redwood becoming available for planting. Although Dawn Redwood does not have wide-spread commercial value, its lumber is similar to that of Coastal Redwood and has been used to make furniture as well as pulp for making plyboard and composite materials.

Dawn Redwood Pollen Cones Dawn Redwood Trunk Metasequoia is a fast growing tree — some of the oldest U.S. trees (planted in 1948) have attained diameters of over 1 meter. Dawn Redwood can be distinguished from Bald Cypress by several characteristics — the buds develop on the underside of the branches not along the tops; the leaves are opposite, not alternate; the base of the trunk is fluted and buttressed; and the branches have rounded depressions below their junction with the trunk. The light brown pollen cones are borne on long stalks appearing in early spring; the inconspicuous female cones are borne singly.

Invasive Shrubs, Vines, and Trees

Invasive plants are non-native species that aggressively invade areas and displace native species. These plants may have been introduced by gardeners or transported from other countries by accident. Examples of invasive shrubs, vines, and trees commonly encountered at the Arboretum are shown below. These species are listed in the “Severe Threat” category by the Tennessee Exotic Pest Plant Council (tneppc.org/invasive_plants) and present management challenges as well as research opportunities. More detailed descriptions of these can be found by clicking on the individual links below.

Autumn Olive

Chinese Privet

Autumn Olive
(Eleagnus umbellata)

Chinese Privet
(Ligustrum sinense)

Multiflora Rose

Mimosa

Multiflora Rose
(Rosa multiflora)

Mimosa
(Albizia julibissin)

Japanese Honeysuckle

Oriental Bittersweet

Japanese Honeysuckle
(Lonicera japonica)

Oriental Bittersweet
(Celastrus orbiculatus)

Tree-of-Heaven

Princess Tree

Tree-of-Heaven
(Ailanthus altissima)

Princess Tree
(Paulownia tomentosa)


View a list of Previously Featured Plants

Please help us preserve our natural heritage!
No collecting of plant materials is permitted at the UT Arboretum.

University of Tennessee - Forest Resources AgResearch and Education Center
901 South Illinois Avenue, Oak Ridge, Tennessee 37830 · Telephone: 865-483-3571 · Email: UTforest@utk.edu