Persimmon (Diospyros virginiana)

September 22 - 29

Persimmon is a moderately sized tree growing to 60 feet tall and 2 feet in diameter. It is the most northern member of the Ebony family — other members of the family are tropical or subtropical. A Persimmon tree found just above the end of the Tulip Poplar Trail is currently loaded with orange fruit that will become deep purple as they mature during the next few weeks.

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 Flowers

September 15 - 22

A walk along Scarborough Creek below the Magnolia Orchard and in the Marsh Area provides a good view of a variety of fall wildflowers along the stream banks. A sample of these are highlighted at left. Clockwise from upper left: Spotted Touch-Me-Not (Impatiens capensis), Cut-Leaf Coneflower (Rudbeckia laciniata), Turtlehead (Chelone glabra), Cardinal Flower (Lobelia cardinalis), Great Blue Lobelia (Lobelia siphilitica). Center: Sweet Joe-Pye Weed (Eupatoreum purpureum).

Resurrection Fern (Pleopeltis polypodioides)

September 8 - 15

Among the interesting ferns found at the Arboretum is the Resurrection Fern which can be observed on several Eastern Red Cedar trunks along the Cemetery Ridge Trail. It also occurs on rocky ledges off the trails. The fern is an epiphyte (or air plant) — a plant that uses another plant as a substrate but does not depend on that plant for food, nutrients, and water as does a parasitic plant.

During dry periods, the fern’s fronds appear shriveled. The common name is based on the fern’s ability to expand quickly (i.e., resurrect) in response to a rainy period, such as the rain we had at the end of August. The fern obtains its water and nutrients directly from rainwater and the wet bark or other substrate on which it grows. Resurrection Fern is widely distributed in Tennessee and the Southeastern U.S.

Honey Locust (Gleditsia triacanthos)

September 1 - 14

As you walk along Marsh Road, you will find two large trees with large thorns on their trunks. These Honey Locusts (or Sweet Locusts) have abundant yellowish, bean-like pods hanging down from the branches. The compound leaves are bi- or tri-pinnate (leaves divided two or three times). The native range of Honey Locust extends from central Pennsylvania south along the Appalachians to Alabama and west to Texas and the Central U.S.

Honey Locust belongs to the plant family Fabaceae (the bean or pea family). The large pods, which are yellowish now, turn brown as fall progresses and may persist into winter. The pods are sweet and eaten by cattle, hogs, and wildlife (thus the name "honey" or "sweet"), and the rattling of the seeds in the pods is said to resemble the singing of locusts (thus the second part of the common name).

The conspicuous thorns on the trunk and limbs are modified branches—they occasionally bear leaves. These have likely evolved over geologic time as protection against large herbivores. In the past, the very hard thorns have been used as nails, for carding wool, and as pins for closing sacks. The durable wood has been used for railroad ties, fence posts, and pallets. A number of thornless varieties have been developed for shade and ornamental use.

Eastern Red Cedar (Juniperus virginiana)

September 1 - 7

Eastern Red Cedar (also known as Old Field Juniper) is a small to medium sized coniferous tree with scale-like or awl-like leaves and bluish, berry-like fruits. It is widespread throughout the eastern U.S. and adjacent Canada. It invades open areas that have been disturbed by fire or cleared for agriculture. Areas dominated by Eastern Red Cedar are referred to as “Cedar Barrens” and are present in the Oak Ridge area. Eastern Red Cedar trees may persist in older forests for many years, and their presence may provide evidence of past land use for agriculture or other human or natural disturbance.

The female cones of Eastern Red Cedar develop into bluish “berries” with a waxy coating. These fruits are an important winter food source for birds, which disperse the seeds widely.

The aromatic wood repels insects and is used for lining cedar chests and as fence posts. The tree is also planted for windbreaks and used for making pencils and for Christmas Trees in the South. It is an alternate host for cedar-apple rust and should not be planted near fruit trees .

Northern Catalpa (Catalpa speciosa)

August 18 - 25

Two large Northern Catalpa trees (also known as Indian Bean Tree or Cigar Tree) are found near the Juniper Collection, east of the Arboretum Program Shelter. The genus name Catalpa purportedly comes from a Cherokee Indian word for “bean tree” — the seed pod, which is conspicuous at this time of year, has a long, bean-like shape. Catalpa belongs to the Bignoniacea family, which also includes Cross Vine and Trumpet Creeper.

The natural range for Northern Catalpa includes western Tennessee and other parts of the Central Mississippi Valley. It has been widely planted in urban areas and on farms to provide materials for fence posts. The showy white flowers that give rise to the elongate seed pods appear in late spring.

American Hornbeam (Carpinus caroliniana)

Late-July to October

American hornbeam (also known as ironwood, muscle-wood, blue beech) grows abundantly along Scarboro Creek Road. At this time of year the maturing fruit clusters hang down from the canopy. These consist of a 4-6 inch stalk with a series of 3-lobed, leaf-like bracts — the small nutlets are found at the base of these bracts. A related tree, European Hornbeam, is found along the Heath Cove Trail.

Common names of this tree are related to its bark and wood. The dense wood dulls woodworking tools (ironwood) and takes a horn-like polish (hornbeam). The muscle-like bark has sinewy, muscle-like ripples, (muscle-wood) and its otherwise smooth, blue-gray appearance resembles beech bark (blue-beech). The wood has been used for tool handles, bowls, and ox yokes. The fruits and buds are eaten by birds, squirrels, and deer. This understory tree occurs along streams and other low areas throughout the eastern U.S.

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.

Cornelian Cherry Dogwood (Cornus mas)

Late July 14 - 21

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.

Black Cherry (Prunus serotina)

Late July 7 - 14

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.

Lizard's Tail (Saururus cernuus)

Late June - July

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's-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.

June Featured Plants
May Featured Plants
April Featured Plants

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