Vernal Witch Hazel (Hamamelis vernalis)
It's always somewhat surprising to find wildflowers in January, but despite cold temperatures, a shrub next to Scarboro Creek just below the Arboretum Visitors Center blooms late in the month. Vernal Witch Hazel is a native of the Ozark and Ouitchita Mountains. Its very fragrant flowers vary in color from yellow to purplish-red and usually bloom in late January or early February. The common name Witch Hazel purportedly comes from the belief that witchcraft allowed the crooked stems of the shrub to be used for divining water. The flowers of our native American Witch Hazel (Hamamelis virginiana) have 4 yellow strap-shaped petals and are less showy than those of Vernal Witch Hazel. Witch Hazel belongs to the plant family Hamamelidaceae. The only other genus in this family native to the U.S. is Sweetgum (Liquidambar styraciflua).
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Viburnums (Viburnum species)
April and May are prime times to see Viburnums in bloom. The UT Arboretum Society has recently enhanced the Arboretum's Viburnum collection with 67 new plants including 20 species and 38 forms. These are planted along Valley Road between the gate and the Dwarf and Unusual Conifer Collection. As these shrubs develop, they will provide a beautiful spring display and provide visitors an opportunity to observe some of the diversity available with these popular landscape plants.
Two examples of our established Viburnums were in bloom near the Visitors Center towards the end of April and beginning of May.
Leatherleaf Viburnum (Viburnum rhytidophyllum) is one of the earliest shrubs to bloom in the spring. Its opposite, evergreen leaves are dark green and have a leathery texture. The fragrant, creamy white flowers are borne in dense terminal clusters (cymes). The fruits are initially red, but become black as they mature. The shrubs sucker readily and grow to heights of 15 ft or more.
Two Chinese Snowball Bush Viburnums (Viburnum macrocephalum) near the front of the Visitors Center have brilliant, globose clusters of sterile, white flowers that are a beautiful lime green when they first emerge. This species is a native of China, and the sterile form is only known from cultivation; the wild form has both sterile and fertile flowers. It grows to heights of 12-20 ft.
Viburnums were historically classified by botanists as belonging to the Caprifoliaceae (the Honeysuckle family), but recent morphological and biochemical studies have caused them to be reclassified to the Adoxaceae, a family which also includes Elderberries (Sambucus).
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Virginia Pennywort (Obolaria virginica)
This inconspicuous member of the Gentian family blooms in April and May. It was found in mid-May under a Rhododendron along the Heath Cove Trail and is likely to be seen at other locations around the Arboretum. Virginia Pennywort is described as being mycotrophic, a type of symbiotic relationship involving a mycorrhizal fungus that is also associated with the roots of a photosynthetic woody plant. As a result, there is a three-way relationship that involves the flow of carbon, water, and/or nutrients among these plants. The purplish, spatulate leaves and the stems are somewhat fleshy. Obolaria is native to the US, ranging from Pennsylvania and New Jersey south to Florida, and west to Texas, Indiana, and southern Illinois. It has been used by Indians as a cough medicine, a diaphoretic, and as a poultice for treating cuts and bruises.
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Virginia Pine (Pinus virginiana)
Virginia Pine (also known as Scrub Pine) is one of the more common native pines found at the Arboretum. Its twisted, yellowish-green needles are borne in bundles of two, a characteristic that helps distinguish it from Shortleaf Pine which has straight needles in bundles of 2-3. Trunks of older Virginia Pine retain many dead limb stubs below the canopy. The flaky bark is light brownish orange to gray-brown. The seed cones, which require 2 years to mature, have scales with thickened ends bearing slender, stiff prickles. Pollen cones develop in the spring and produce copious amounts of pollen.
Virginia pine, which may grow up to 70 ft in height, is a pioneer species that becomes established in open areas created by fire or other disturbance. The presence of older Virginia Pines in the Arboretums deciduous forest reflects a history of forest development on abandoned farmlands. Research at UT on Virginia Pine has included studies of genetic and environmental variability that influence tree growth and productivity.
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