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Jack-in-the-Pulpit (Arisaema triphyllum)

Jack-in-the-Pulpit Jack-in-the-Pulpit, a late spring wildflower, is found throughout the Eastern U.S. Numerous examples can be seen in the Arboretums wildflower garden next to the Visitors Center in April and May. Its unusual inflorescence is enclosed by a purple- to green-striped sheathing bract (the pulpit) called a spath. The inflorescence (the Jack) is called a spadix and consists of a fleshy axis covered with tiny flowers.

Jack-in-the-Pulpit has been used for medicinal purposes. Although parts of the plant are considered edible, they contain calcium oxylate crystals which when eaten raw can cause irritation or serious breathing problems.

Jack-in-the-Pulpit Leaves The compound basal leaves have 3 leaflets that superficially resemble poison ivy.

Jack-in-the-Pulpit has been used for medicinal purposes. Although parts of the plant are considered edible, they contain calcium oxylate crystals which when eaten raw can cause irritation or serious breathing problems.

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Japanese Honeysuckle (Lonicera japonica)

Japanese Honeysuckle Japanese Honeysuckle

Japanese Honeysuckle is an exotic, invasive vine that is found along forest edges, fence rows, and in forest canopies. In May its very fragrant, white tubular flowers, which turn yellow with age, are borne in pairs at the leaf nodes. A long tube inside the corolla is filled with a honey-like nectar. Children enjoy removing the white blossom and sucking out the few drops of sweetness from the long inner tube thus the common name Honeysuckle.

A native of Japan and China, this vine can climb more than 30 ft and spread over a trees canopy to the point of shading it out and killing the tree. Its runners can also twist tightly around the stems of smaller plants and essentially strangle them by cutting off their supply of water through the xylem cells. Japanese Honeysuckle was introduced to the U.S. in the 1860s and has spread throughout much of the country.


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Japanese Larch (Larix kaempferi)

Japanese Larch As you walk through the Arboretum's Marsh Area in late October/early November, you may notice a tall conifer with leaves changing from green to bright yellow. This Japanese Larch is native to central and northern Japan. It is planted in Japan and northern Europe (including the British Isles) where its decay resistant wood is used for construction and fences. It is also the most popular of the larches for use in Bonsai. Japanese Larch can grow to more than 100 feet in height with spreading branches that give it a cone-shaped appearance.

Japanese Larch Needles First-year shoots bear single leaves (needles), while older branches bear clusters of needles (up to 60 per cluster) on short shoots. Japanese Larch is one of several deciduous conifers at the Arboretum - others include Dawn Redwood (Metasequoisa glyptostrboides), Bald Cypress (Taxodium disticum), and Pond Cypress (Taxodium ascendens). Typically larches are trees of mountains or high latitudes. Three species of larch are native to North America: Tamarack (Larix laricina) is a component of boreal forests and peatlands in Canada and the northern U.S., extending south into Ohio, Pennsylvania, and West Virginia; Western Larch (L. occidentalis) occurs in the Northwestern U.S. and adjacent Canada; and Subalpine Larch (L. lyalli) grows at or near timberline in the mountains of the Pacific Northwest.

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Red Leaf Japanese Maple (Acer plamatum 'Atropurpureum')

Japanese Maple Japanese Maples are one of the most popular landscape trees available. They are native to Japan, China, Korea, and southeast Russia where they have been cultivated for hundreds of years. A wide assortment of cultivars has been developed, exhibiting many variations in color, leaf size and shape, and overall growth form. An excellent specimen tree of Red Leaf Japanese Maple, planted in 1973, can be seen at the edge of the Arboretum's Shade Tree Collection near the top of the Tulip Poplar Trail and the Flowering Dogwood Research Collection.

Japanese Maple Flowers Japanese Maple Fall Leaf Japanese Maple Fruit

This tree is particularly striking in the late summer and fall with its red to purple foliage. Red Leaf Japanese Maple grows to heights of 20-25 ft and usually exhibits a semi-hemispheric growth form. The palmately divided leaves have 5-7 deeply cut lobes with serrate leaf margins. The bright green leaves that emerge in early April, turn to reddish/purplish hues by early fall. The small, red flowers, which appear in the spring along with the emerging leaves, are borne in stalked umbels. A distinctive feature of this cultivar is that the wings of the paired fruits (samaras) diverge at an obtuse angle. Japanese Maple wood has been used for decorative veneer/plywood, furniture components, and cabinetry.

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Japanese Nutmeg (Torreya nucifera)

Japanese Nutmeg A native of Japan, this small evergreen tree belongs to the yew family (Taxaceae). It is one of five species of the genus Torreya, two of which are native to the U.S. (T. californica and T. taxifolia). A good example of Japanese Nutmeg can be seen at the upper end of the Arboretums Dwarf Conifer Collection next to the Valley Road. The leaves are two-ranked, and when crushed, they have a pungent odor.

Japanese Nutmeg Pollen Cones Double rows of the male strobili (pollen cones) are conspicuous along the underside of some of the branches duriing winnter. The male and female cones are often found on separate branches of the same tree. The fruit is a single seed surrounded by a fleshy structure similar to the aril of yews. The nut-like seeds are edible and are pressed for a type of cooking oil.

In Japan this species may reach a height of 75 ft. The wood is highly valued for construction of boards used for the ancient game of Go. The species has been over-harvested in Japan and has become rare.

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Japanese Stiltgrass (Microstegium vimineum)

Japanese Stiltgrass One of the most aggressive invasive plant species in our region is Japanese Stiltgrass, also known as Nepalese Browntop. This annual grass, a native of Asia, was apparently introduced into Tennessee in the early 1900's, possibly as discarded packing material used for shipping porcelain. Since then, it has become established in many eastern states and as far west as Texas. Japanese Stiltgrass grows in a variety of habitats and thrives under moderate shade where it outcompetes many native species. It produces many seeds which remain viable in the soil for at least 3 years.

Japanese Stiltgrass on the Forest Loop Road Stiltgrass quickly colonizes areas where the natural forest floor's leaf litter has been disturbed, such as along trail edges. Deer and livestock do not eat this grass, and it has been suggested that these animals preferentially select native species thus promoting the invasion of stiltgrass. Control of this species is challenging. Mechanical removal in late summer before seeds are produced can be effective. The UT Arboretum has been the site for two graduate student research projects investigating factors that affect the occurrence, rate of spread, and ecological impacts of stiltgrass in forested areas.

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Japanese Umbrella Pine (Sciadoitys verticella)

June

Japanese Umbrella Pine Needles Japanese Umbrella Pine Bark An interesting tree in the Arboretum's Dwarf and Unusual Conifer Collection is the Japanese Umbrella Pine. Its common name comes from the long green, needle-like "leaves" that occur in whorls resembling the spokes of an umbrella. These photosynthetic "leaves" have been interpreted as actually being stem tissue rather than leaf tissue and are referred to as cladodes. They persist for 3 years. The true leaves are small brown, scale-like structures found along the shoot between the whorls of green cladodes and also tightly clustered around the bases of the cladodes. This slow-growing tree can reach a height of 20-30 feet. Its reddish-brown bark peels off in strips.

Japanese Umbrella Pine In its native Japan, Japanese Umbrella Pine grows in cool, moist, mountainous environments and the wood is used for building boats. Several cultivars have been developed as unusual landscape trees. Japanese Umbrella Tree produces a latex-like sap which has been shown to have antibacterial properties against some human pathogens and soil bacteria. As the sole member of the plant family Sciadopityaceae, the Japanese Umbrella Pine is known from the fossil record as far back as 230 million years. Recent research has suggested that fossil members of this family were the source of Baltic Amber.

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Jujube (Ziziphus jujuba)

Jujube Tree Many people may be familiar with some culinary and herbal uses of Jujube, but may not be familiar with the plant itself. A Jujube tree (also known as Chinese Date) can be found near the Arboretum's Program Shelter, adjacent to the Juniper Collection. A native of China and Japan, Jujube has been cultivated in many parts of the world for centuries and was introduced into the U.S. in the mid-1800's. Its sweet edible fruit can be used for a variety of culinary and medicinal purposes. The fruits can be eaten raw like dates, or used in cooking puddings, cakes, soups, etc. In China and Japan, the fruits, leaves, and roots are used to prepare herbal remedies for treating a wide variety of ailments, including arrhythmias, insomnia, fevers, liver conditions, malnutrition, anemia. They also are used as an aid in weight gain, increasing stamina, and strengthening bones and tendons. The fruit has a very high Vitamin C content. Candies called Jujubes and Jujyfruits may have originally contained extracts from the Jujube tree, but they became just chewy candy with any kind of fruit flavoring.

Jujube Bark Jujube Fruit Jujube belongs to the plant family Rhamnaceae - the same family as our native Carolina Buckthorn (Rhamnus caroliniana). Although a relatively small tree, it can grow as tall as 40 ft. The native species usually has two spines at the base of each leaf and gnarled branches, but our specimen is a cultivar without any spines. The Jujube has alternate, shiny, green leaves (1-2 in. long) that are finely toothed along the margins. The bark is rough and shaggy. The small, fleshy fruit is red (plumb or cherry size) with a single stone and matures in the fall. The fruit becomes wrinkled with age, resembling a date. Jujube has been used as a hedge plant. It has dense, hard, tough wood which has been used for agricultural implements and wood turning. It also makes good fuel and charcoal.

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Katsura (Cercidiphyllum japonicum)

Katsura Tree As you walk along the upper part of Valley Drive in September, you may notice a distinctive odor that had been characterized as "burnt sugar," "caramel," or "cotton candy." This aroma comes from the falling leaves of two deciduous Katsura trees planted in 1965. The Katsura tree is native to moist forests in the mountains and lowlands of Japan and China. These tree are the only living remnant of a large, diverse plant family known from the fossil record.

Katsura Tree is considered to be an excellent shade tree. In China and Japan the soft white wood is used for making furniture and paneling.

Katsura Tree Leaves Katsura Tree Trunk The dark blue green, heart-shaped leaves are 2 to 4 in. wide and turn to an apricot to yellow color in the fall. The scientific genus name Cercidiphyllum refers to the leaves which resemble those of our native Redbud (Cercis). Katsura trees grow to heights of 40 to 60 ft. The trunks flare out at the base, with shallow roots often prominent at the soil surface. The species is dioecious, having male and female flowers on separate trees.

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Kentucky Coffee Tree (Gymnocladus dioicus)

Kentucky Coffee Tree In 1967, several specimens of Kentucky Coffee Tree were planted near the Arboretum Shop area. Over time, the original trees died and were removed, but numerous root sprouts have survived forming two small groves around the stumps. Kentucky Coffee Tree is found throughout Tennessee and ranges from southern Ontario to northern Louisiana and Georgia and west to Oklahoma, Kansas, eastern Nebraska, and southeastern South Dakota. Kentucky Coffee Tree was designated the State Tree for Kentucky in 1976, but legislation was enacted in 1994 to replace it with Tulip Poplar.

Kentucky Coffee Bark Kentucky Coffee Tree Flower Kentucky Coffee Tree Leaves
Kentucky Coffee Tree belongs to the Pea family (Fabaceae). It grows to heights of 60 to 70 ft and has very large compound leaves (1 to 3 ft long by 1.5 to 2 ft. wide). These alternate, compound leaves are bipinnate (i.e., twice compound) with a central rachis having pinna bearing 6-14 leaflets, 1-2 in. long. The genus name Gymnocladus, from the Greek meaning "naked branches," refers to the coarse branches without twigs that are evident in the spring and winter when the large leaves are absent. The dark grayish brown bark has deep fissures with scaly ridges. The reddish brown wood - referred to as "Kentucky Mahogany" - has been used by woodworkers and cabinet makers, and is prized for interior millwork, bridge timbers, and railroad ties. It also is often used as a street tree. Kentucky Coffee Tree is dioecious, having male and female flowers on different trees. The large black to brown seed pods (3-8 in. long) contain seeds with very hard coats that were roasted by early American settlers as a coffee substitute - the basis for the common name "Coffee Tree." The leaves and uncooked seeds are potentially toxic.

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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