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.
Redbud (Cercis canadensis)
Early April
One of the most beautiful and conspicuous trees at the Arboretum in April is the Redbud. This tree is most commonly seen at forest edges, in disturbed areas, or in managed landscapes. Redbud is a member of the bean family (Fabaceae), and in a natural setting is an early invader of disturbed areas where it grows quickly but is generally short lived (20-25 years). Distinguishing characteristics of Redbud include its rose-pink, pea-like flowers, its heart-shaped leaves, and its flat, brown, bean-like pods.
At the Arboretum you will see Redbud along several trails and bordering some open areas. A research planting near the Program Shelter is in full bloom. The larger trees in this area are survivors of a failed research study originally planted in 1995. A new planting of redbuds was made in 2007 next to these older trees; the young trees are just becoming established. The objective of the current study is to evaluate Chinese Redbuds and ones from a northern location in the United States for potential introduction in Eastern Tennessee.
Beech Leaves (Faxus grandifolia)
Mid April
Visitors to the Arboretum often ask "What is that tree with brown leaves on it all winter long?" The answer is the Beech tree, which is conspicuous along our trails with its golden-brown leaves of fall gradually becoming a duller brown as the winter progresses. In the spring, these leaves drop as the spear-shaped buds expand.
Mayapple (Podophyllum peltatum)
Mid to Late April
Mayapple is found throughout the Arboretum in small to large patches. It is especially conspicuous along the Oak-Hickory trail and parts of the Cemetery Ridge Trail at this time of the year.
Look for plants with two palmate leaves – the white flowers are found at the base of the petioles (stalks) of the two leaves. The flower appears in late April/early May, and the pulpy fruit (the “apple”) appears later in the spring – thus the name Mayapple. Although the leaves and roots are poisonous, extracts from the roots have been used for medicinal purposes for many years.
Trillium (Trillium species)
Mid to Late April
There are at least three species of Trillium present on the Arboretum: Large-Flowered Trillium (Trillium grandiflorum), Yellow Trillium (T. luteum), and Sweet Betsy (T. cuneatum). These are found along the Heath Cove Trail and scattered elsewhere on the Arboretum. The flowers are currently at their peak.
Trillium comes from the Greek word "tris" meaning three - the leaves and flower parts all occur in "3's." Species with sessile flowers (no flower stalk) are known as "Toadshades" while those with stalked flowers are "Wakerobins." Trillium leaves are edible and the roots and leaves have been used for medicinal purposes.
Silverbell (Halesia tetraptera)
Mid to Late April
Silverbell can be seen in several locations at the Arboretum — just below the Visitors Center near Scarborough Creek, along the lower Heath Cove Trail, and near the Program Shelter. It is a tree that is most typical of the southeastern mountains, but forms can be found throughout the southeastern and central U.S. Silverbell is in bloom this week and is readily recognized by its showy white, bell-shaped flowers hanging down from the branches. In late summer and fall, the green to brown, papery, 4-winged fruit has a long spike-like projection at its bottom.
A research collection near the Program Shelter was established in 1997 to evaluate ornamental characteristics, hardiness, and growth rate of trees obtained from 4 geographical areas in Tennessee, North Carolina, Arkansas, and West Virginia. Silverbell’s wood is valued for making furniture and wood carvings. Several cultivars have been developed for landscaping.
Pawpaw (Asimina triloba)
Mid to Late April
A planting of Pawpaws below the Program shelter began blooming in early April. Colonies of Pawpaw are also found along several trails, but these rarely bloom. Pawpaw is the northernmost member of the subtropical and tropical plant family Annonaceae. The bell-shaped flowers have six brown to purple petals. The stamens and pistils are borne on a raised receptacle. The flowers have a fetid smell that attracts beetles and flies as pollinators.
The large, fleshy, edible fruit (up to 16 cm long)
matures in September and October and has been described as having a taste similar to a mixture of banana, mango and pineapple.
Pawpaws are eaten raw or processed into deserts such as pies and ice cream, though they may cause stomach trouble for some people. They are eaten by a variety of wildlife. Recent research indicates Pawpaw has potential as an anti-cancer drug and as a pesticide. It is found throughout the Eastern U.S.,
except in New England, and as far west as Nebraska.
Tulip Poplar (Liriodendron tulipifera)
Late April to Early May
Tulip Poplar (or Yellow Poplar) is the state tree of Tennessee and is found throughout the Arboretum, where it is a prominent member of the deciduous forest replacing shortleaf and Virginia pines. Tulip Poplar is recognized by its tall straight trunks, its tulip-shaped flowers, and its distinctive leaves.
Because the yellow-green, tulip-shaped, upright flowers are found high in the tree canopy, they are often difficult to see. Look for yellow to cream flower parts on the ground beneath the trees; then look up to see the flowers. Tulip Poplar belongs to the Magnolia Family - two other native members of this family are found in the Arboretum forests - Cucumber Magnolia (Magnolia acuminata) and Umbrella Magnolia (M. tripetala). Look for these native species as you walk the Arboretum trails.
Little Brown Jug (Hexastylis arifolia var. ruthii)
Late April - Early May
Little Brown Jug is a perennial, evergreen wildflower that can be seen along many of the Arboretum's trails. Its unusual urn-shaped (or jug-shaped) flower is found at ground level, usually covered by leaves and other forest litter. The shiny, arrowhead-shaped leaves and glabrous flowers arise from an underground stem (rhizome). The sepals are fused into an urn-shaped, brown to reddish brown calyx tube (there are no petals) with pointed tips at the top. Within the urn are 12 stamens and a superior or partly inferior ovary having 6 styles.
Little Brown Jug belongs to the same plant family (Aristolochiacease) as Wild Ginger ( Asarum canadense), which has pubescent, heart-shaped leaves and a calyx tube that terminates in spreading or reflexed tips. The rhizome of both plants has an odor similar to ginger (as do the crushed leaves) and was used as a substitute for that spice by early settlers. Flowers of Little Brown Jug are pollinated by beetles and other insects in the leaf litter. Little Brown Jug is found throughout the Southeast. Native Americans used it for treating such ailments as stomach pains, whooping cough, heart problems, and asthma.
Crossvine (Bignonia capreolata)
Late April - Early May
Crossvine is one of three members of the Bignoniaceae plant family found in our area — the other two being Catalpa (the bean tree) and Trumpet Creeper (Campsis radicans), both of which flower later in the year. Crossvine is in full bloom the last week of April and the first week of May. It is especially conspicuous on trees near Scarborough Creek along Old Kerr Hollow Road and in several places along the Cemetery Ridge Trail. It can also be seen driving along the Pellissippi Parkway as one approaches the Arboretum from Oak Ridge.
Crossvine can grow to more than 50 ft in length. Its compound leaves have three leaflets, the terminal one modified into tendrils that enable it to climb. These leaf characteristics differentiate it from Trumpet Creeper which has many leaflets, no terminal tendrils, but aerial rootlets for climbing. Crossvine has orange-red flowers while those of Trumpet Creeper are red. The tubular flowers of both Crossvine and Trumpet Creeper attract hummingbirds at different times of the growing season. Crossvine derives its common name from the fact that the pith of a cut stem often appears as a dark, cross-like center.
Fly Poison (Amianthium muscitoxicum)
Late April thru June
Fly Poison or Stagger Grass is a member of the Lily Family and is conspicuous along the Oak-Hickory Trail from April through June. It has grass-like basal leaves and at full bloom a spectacular cylindrical, white inflorescence. Although the distribution of Fly Poison is reported to be throughout the Southeast, extending as far west as Oklahoma and as far north as New York, it is found infrequently in a range of habitats from wetlands to pine-oak forests. It is only known from one area at the Arboretum (along the Oak-Hickory Trail.)
All parts of the plant are toxic, especially the bulb. In the past, sugar or honey mixed with crushed portions of the bulb was used to kill flies. Cattle and sheep may eat the plant when other forage plants are limited. The toxic alkaloid contained in the plants can cause the animals to stagger around before dying - thus the origin of the common name "Stagger Grass."
Return to Featured Plants
January Featured Plants
February Featured Plants
March Featured Plants
April Featured Plants
May Featured Plants
June Featured Plants
July Featured Plants
August Featured Plants
September Featured Plants
October Featured Plants
November Featured Plants
December Featured Plants
Please help us preserve our natural heritage!
No collecting of plant materials is permitted at the UT Arboretum.
|
