University of Tennessee Forest Resources Research Center

A walk in the Marsh Area reveals a large colony of Lizard’s-Tail (also known as Water Dragon) growing along the creek bank. This aquatic plant has an inflorescence that resembles a bottle brush made up of a dense cluster of white flowers. As the fruits mature, the brown inflorescence is said to resemble a lizard’s tail.

Lizard-Tail grows along ditches, streams, ponds, and in other wetland situations. It is a popular water garden plant. Over time, the plant has been used as a general medicine for a variety of illnesses. Lignan compounds and other chemicals in Lizard-Tail have been shown to provide it with chemical defense against aquatic herbivores such as crayfish. Recent biochemical studies indicate that compounds from this plant have potential for treatment of tumors.

Buttonbush (Cephalanthus occidentalis)

In the first week of July, a Buttonbush located along Scarborough Creek near the entrance to the Arboretum displayed the impressive white spheres of tightly compressed flowers that give rise to its common name. This shrub, a member of the Madder Family (Rubiaceae), may grow to a height of 20 ft. Its leaves are mainly opposite, but whorls of three leaves may occur just below the inflorescence.

It occurs along the edges of wetland habitats such as stream banks and marshes from Southern Canada south to Florida and west to the Great Plains. It can also be found in New Mexico, Arizona, California and northern Mexico.

Although the leaves are poisonous to cattle, waterfowl and song birds eat the small nutlets, and the shrub provides excellent cover for a variety of birds and wildlife. Buttonbush has been used for medicinal purposes by Native Americans. The bark contains an alkaloid, cephaeline, which is used in medications to induce vomiting, but it also contains cephalanthin, a poison that dissolves blood corpuscles.

Black Cherry (Prunus serotina)

Early to Mid July

Black Cherry is commonly found along many trails at the Arboretum. Under a dense forest canopy, the trees are often small and shrub-sized with few flowers or fruits. Larger trees can be found in more open areas such as forest edges or forest openings where the fast-growing black cherries can better compete for light.

Black cherries which are relished by birds and other small animals have been ripening this past week. Birds distribute large numbers of the seeds widely. Trees loaded with fruit can be seen near the Program Shelter next to the dogwood plantings and just below the Shade Tree Orchard. The bark of young Black Cherries is smooth and reddish brown or gray with well-defined horizontal lenticels.

Older trees have more furrowed, platy bark which turns up at the edges. In the past, extracts of the bark have been used in cough medicines and various tonics. The leaves and twigs contain a cyanide compound which has been implicated in the death of horses and other livestock. The wood is used extensively for veneer, furniture, and lumber.

Cornelian Cherry Dogwood (Cornus mas)

Cornelian Cherry Dogwood is a small tree or shrub native in southern or central Europe and western Asia. In these areas, the bright cherry-red fruit is used for syrup and preserves. As a landscape plant it can be used for a shrub border, hedge, screen, and foundation planting around large buildings. Its yellow flowers appear early in the spring before most other flowering shrubs, making it an attractive landscape feature.

An Arboretum research collection is present just west of the Juniper Collection. The project was initiated in 1997 to identify plants with exceptional ornamental value (flowering, fruiting, and form) that are hearty in this climate. Value to wildlife is also being considered. Seeds for these plants were collected from native trees growing in Romania and Croatia.

Chinese Privet (Ligustrum sinense)

Chinese Privet, an invasive, non-native shrub or small tree, is found in a variety of habitats at the Arboretum, including wetlands, upland forests, and disturbed areas. It is a native of Southeast Asia that was introduced into the US as an ornamental in the mid-1800’s and has subsequently spread throughout the East and Southeast. Once established, it produces vigorous root sprouts and can outcompete native species, completely taking over an area. Its abundant dark blue fruit is eaten by birds and other wildlife, and the seeds are widely dispersed by them.

A member of the Olive Family (Oleaceae), Chinese Privet is semi-evergreen with opposite leaves, gray bark, and dense clusters of fragrant white flowers in the spring. At the Arboretum, it is especially conspicuous in forest edges along Arboretum Drive, Cemetery Ridge trail, and as scattered clumps along Scarborough Creek. It is difficult to control, as it rapidly sprouts back from roots and stumps when cut back. Its leaves have a high content of phenolic compounds that protect it from insects and other herbivores. The UT Forest Resources Center, in cooperation with UT faculty, is presently engaged in the testing of new herbicides to help eradicate privet and other invasive, non-native plants.

Hardy Orange (Poncirus trifoliata)

An unusual and interesting shrub is located at the edge of the Shade Tree Collection near the top of the Tulip Poplar Trail Spur. Hardy Orange (or Trifoliate Orange) is a member of the Rutaceae plant family and closely related to the Citrus genus. It is a native of China and Korea that has been introduced into the US. In parts of the Southeast, it has escaped cultivation and can be an invasive species in fencerows, roadsides, and forest edges. The compound leaves have three leaflets, and the branches terminate in conspicuous thorns.

Although the green fruit, which turns dull yellow in the fall, has been used for making marmalade, it may cause severe stomach pain, nausea, and skin irritation. Hardy Orange is a cold hardy, disease resistant plant that is used as a root stock for commercial citrus. Historically, it was planted for hedgerows because its vicious thorns make it virtually impenetrable. Thus its presence can indicate abandoned home sites.

Devil's Walking Stick (Aralia spinosa)

Mid-July to Mid-August

As you walk to the end of Marsh Road, look to the right for a dense thicket of Devil’s Walking Club that exhibits large terminal clusters of creamy white flowers and large compound leaves. This relatively small tree gets its name from the club-shaped branches and the “vicious” prickles along the trunk, especially at the nodes. The prickles only form during the first year of growth, and as the tree matures the older stems gradually lose their prickles.

Leaves are doubly or triply compound and may be up to 5 feet in length, with individual leaflets 2-4 inches long. The purple to black fruits mature in late summer and early fall and are eaten and dispersed by birds; the foliage may be browsed by deer. Devil’s Walking Stick is native to the southeast, but has been successfully introduced to many other parts of the eastern U.S.

Lizard's Tail (Saururus cernuus)

Buttonbush (Cephalanthus occidentalis)

Black Cherry (Prunus serotina)

Cornelian Cherry Dogwood (Cornus mas)

Chinese Privet (Ligustrum sinense)

Hardy Orange (Poncirus trifoliata)

Devil's Walking Stick (Aralia spinosa)