University of Tennessee Forest Resources Research Center

A major research collection of Cornelian Cherry Dogwood cultivars is present along Arboretum Drive and behind the Juniper Garden and Conifer Collection. Cornelian Cherry Dogwood is a multi-stemmed, small tree or shrub native to Central and Southern Europe and Western Asia. The fruit, which matures in summer, is bright red and olive-shaped. In its native habitat the fruit is used for syrup and jams. This Dogwood is one of the earliest flowering trees at the Arboretum - the first blooms were evident in the collection this past week (February 17). The numerous, small yellow clusters of flowers appear before the leaves. The objective of the ongoing research study is to identify plants with exceptional ornamental value (flowering, fruiting, and form) that are hearty in this climate. The seeds for the collection were obtained from native trees in Rumania and Croatia.

Winter Jasmine (Jasminum nudiflorum)

As we progress through the month of March, our anticipation for discovering spring flowers rises. Meanwhile, a few winter-blooming plants such as Winter Jasmine must satisfy our thoughts of spring. This spreading shrub has been in bloom near the Program Shelter for the past several weeks and will continue to flower sporadically throughout March. Its bright yellow tubular flowers extend from the axils of the green, angled stems and appear before the leaves come out.

Winter Jasmine was originally imported from China to Britain in the 1840s. It provides a good ground cover, particularly on sloping ground or raised structures where it can cascade downward. It is often mistaken for Forsythia, but blooms earlier and for a longer period. It can also be readily distinguished by its green shoots and spreading habit.

Roundlobe Hepatica (Hepatica americana)

Early to Mid March

One of the earliest blooming wildflowers found along Arboretum trails, Roundleaf Hepatica, was seen on March 4th on the lower portion of the Cemetery Ridge Trail. The flower emerges from the decomposing forest leaf litter as a bright spot of blue or white. The showy sepals (it has no petals) are subtended by green bracts. Its leaves are intermingled with the brown leaf litter and are often difficult to see. The leaf color varies from faded green to purple - the ones present now have persisted from the previous season and allow the plant to photosynthesize during the winter months. New leaves are formed after blooming.

Two species of Hepatica are found in our area. The 3 lobes of Roundlobe Hepatica are relatively shallow and rounded at the tips, while leaves of Sharplobed Hepatica (Hepatica acutiloba) are more deeply lobed and have acutely pointed tips. The genus name Hepatica is based on the resemblance of the leaf to the liver. Hepatica has been used for a variety of medicinal purposes - in the late 1800s, more than 400,000 pounds of dried leaves were used in one year to make a tonic for liver ailments.

Bloodroot (Sanguinaria canadensis)

One of the harbingers of spring at the Arboretum is Bloodroot, a member of the Poppy family. At this time, it is in full bloom in the wildflower garden adjacent to the Visitors Center; it should soon be making an appearance along the Oak-Hickory Trail and elsewhere at the Arboretum. When it emerges, the distinctive leaves are clasping the flower stalk, but shortly after emergence, they gradually open up. Typically Bloodroot flowers have 8-12 petals with the upper ones often being somewhat larger than the lower ones - some of the plants in our wildflower garden, however, have almost twice as many petals. The common name Bloodroot is based on the red-orange sap that oozes from the underground rhizome and other parts of the plant when cut. Although the plant has been used for medicinal purposes, the alkaloids in the extracts can be toxic if ingested.

Spicebush (Lindera benzoin)

Spicebush is an early blooming shrub that is found on the banks of Scarboro Creek below the Visitors Center and along several of the Arboretum’s trails. It is also in flower in the wildflower garden at the Visitors Center. Spicebush is dioecious (i.e., it bears male and female flowers on separate plants). When in bloom, the shrub is covered with many small yellow-greenish flowers that appear before the leaves.

Three of the Spicebush plants found in the wildflower garden have pistillate flowers while the one close to the bridge entering the Marsh area is male. The crushed leaves and twigs are aromatic, which is the basis for its common name. In the fall, the shrub bears bright red, oblong fruits which persist into the winter and provide a food source for birds.

Rue Anemone (Thalictrum thalictroides)

Late March to Early April

A single Rue Anemone was found in bloom on March 20th, but by the end of the week numerous flowers were open, and the compound leaves had expanded. Rue Anemone, or Wind Flower, belongs to the buttercup family. The basal leaves are divided into nine leaflets, each of which has three rounded lobes. The flowers are white to pinkish with several flowers being borne in an umbel - i.e., on a long stalk with several branches originating from a common point. These plants can be seen at a low point along the Cemetery Ridge Trail, in the same general location as the Roundlobe Hepatica seen earlier in March.

Other wildflowers soon to come include Mayapple (palmate leaves have emerged), Fly Poison (dark green clusters of basal leaves are particularly conspicuous along the Oak-Hickory Trail), and violets. Red Maple flowers have been in full bloom over the past month, and the red flowers parts have been, and are being, shed along the trails. The Magnolia Orchard has passed its peak bloom, and the ground is covered with purple, red, pink, and white tepals.

Cornelian Cherry Dogwood (Cornus mas)

Winter Jasmine (Jasminum nudiflorum)

Roundlobe Hepatica (Hepatica americana)

Bloodroot (Sanguinaria canadensis)

Spicebush (Lindera benzoin)

Rue Anemone (Thalictrum thalictroides)