US National Arboretum



Arboretum Introduces Oakleaf Hydrangeas for Small Landscapes


munchkinIf you’ve always wanted an oakleaf hydrangea in your garden, but existing cultivars were too large, then you’re in luck. The U.S. National Arboretum has just released two new compact forms of oakleaf hydrangea (Hydrangea quercifolia), a shrub native to the southeastern U.S. ‘Ruby Slippers’ grows to about 3.5 feet tall and 5 feet wide and has large panicles of flowers that mature to a deep rose color. ‘Munchkin’ is slightly smaller, at 3 feet tall and 4.5 feet wide, and has flowers that age to a medium pink color. Both cultivars are hardy from zones 5 to 8 and can be grown in light shade or full sun. They are ideal for the shrub border, as a deciduous hedge, or for mass plantings in large areas.

‘Ruby Slippers’ and ‘Munchkin’ were developed at the arboretum’s worksite located at the Tennessee State University Nursery Research Center in McMinnville, TN. They are the result of approximately 12 years of controlled pollinations, selection, and testing. Prior to their release, ‘Ruby Slippers’ and ‘Munchkin’ were evaluated by cooperators throughout the U.S. It is expected that these new cultivars will be available in the retail market in 2011. Check out our ‘Ruby Slippers’ and ‘Munchkin’ fact sheets for more information on these exciting new plants.

The U.S. Department of Agriculture, Agricultural Research Service, U.S. National Arboretum announces the release of ‘Ruby Slippers’ (NA 74836; PI 658493) and ‘Munchkin’ (NA 73936; PI 658494), two new Hydrangea quercifolia cultivars. ‘Ruby Slippers’ and ‘Munchkin’ are the first releases of the hydrangea improvement program at the U.S. National Arboretum’s McMinnville, Tennessee, worksite, which is located at the Tennessee State University Otis Floyd Nursery Crop Research Center. Both releases were bred by Sandra Reed and are compact forms of oakleaf hydrangea, a shrub native to the southeastern U.S. They are well-suited for use as specimen plants, in mass plantings, or in the shrub border. Because of their small size, they are particularly useful in small residential landscapes.

ruby slipperHydrangea quercifolia ‘Ruby Slippers’ was selected for its compact plant habit and upright inflorescences that age to a deep rose color. It is a small shrub that has grown 3.5 feet high and 5 feet wide in 7 years in McMinnville, TN. In early summer, ‘Ruby Slippers’ is covered with 9-inch-long inflorescences that are held upright above the foliage. Flowers open white, but quickly turn pale pink and then deepen to rose. ‘Ruby Slippers’ originated from a controlled cross between oakleaf hydrangea cultivars ‘Pee Wee’ and ‘Snow Queen’ that was made in 1998.

Hydrangea quercifolia ‘Munchkin’ was selected for its compact plant habit and upright inflorescences that age to a medium pink. It is a small shrub that has grown 3 feet high and 4.5 feet wide in 9 years in McMinnville, TN. In early summer, ‘Munchkin’ produces abundant, 6.5-inch-long inflorescences that are held upright above the foliage. Flowers open white and gradually turn medium pink. ‘Munchkin’ originated from open-pollinated seed collected from the oakleaf hydrangea cultivar ‘Sikes Dwarf’ in 1997.

Both cultivars are hardy in USDA zones 5 to 8 and can be grown in full sun or light shade. Plants are readily propagated in the nursery from softwood cuttings using 4000 ppm IBA, with rooting occurring within four to six weeks. ‘Ruby Slippers’ and ‘Munchkin’ have been evaluated by cooperators in Alabama, Florida, Georgia, Illinois, Kentucky, Maryland, Mississippi, Missouri, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, and Virginia. These cultivars have not shown unusual features that would indicate potential invasiveness.

Plants were distributed to cooperating nurseries for evaluation in 2006 and 2007, and for stock increase in 2008. The U.S. National Arboretum does not have stock plants of ‘Ruby Slippers’ or ‘Munchkin’ available for general distribution, but can provide a limited number of cuttings to interested propagating nurseries. The U.S. National Arboretum can also provide a list of propagating nurseries offering these plants for sale. Requests for this list should be addressed to: Dr. Sandra Reed, U.S. National Arboretum, 472 Cadillac Lane, McMinnville, TN 37110, or The names ‘Ruby Slippers’ and ‘Munchkin’ will be registered with the International Registration Authority for Hydrangea in accordance with the International Code of Nomenclature for Cultivated Plants, 1995. Genetic material of this release will be deposited in the National Plant Germplasm System where it will be available for research purposes, including development and commercialization of new cultivars. It is requested that appropriate recognition be made if this germplasm contributes to the development of a new breeding line or cultivar.

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Last Updated   February 17, 2010 8:50 AM