The Enid News and Eagle, Enid, OK

April 26, 2014

Oklahoma Provens work well

By Deloris Castor, Master Gardener
Enid News and Eagle

ENID, Okla. — Each year a set of plants is chosen by horticulturists that will help consumers choose plants appropriate for state gardens.

The program began in 1999 by selecting a tree, shrub, perennial and annual worthy of Oklahoma landscapes. In 2009 a new category was added, the Collector’s Choice. It is a plant that will do well in Oklahoma and may need special placement, but will be rewarding and impressive in the garden.

To see all the plants recommended by the Oklahoma Proven Plant Selection Program, visit the website at

• Annual: Big twister corkscrew rush (Juncus effesus). Corkscrew rush with its uniquely twisted stems, though relatively small (18-24 inches high and wide) still commands attention in any garden space. The stems curl and spiral around creating a tangled mass. Corkscrew rush prefers very moist to wet conditions in full sun to part shade. Happy submerged in water, it is perfect for a water garden. It also is an excellent accent plant for containers and is spectacular in cut flower arrangements. Though considered hardy to Zone 6, it tends to be a tender perennial in our area. Use as an annual.

• Shrub: Blue muffin viburnum (Vivurnum dentatum). Blue muffin viburnum is a small compact version of the native arrowwood viburnum growing about 3 feet to 5 feet high and just as wide. Blue muffin prefers moist, well-drained soils. Established plants are somewhat drought tolerant and have no serious pest problems and require little maintenance, making them excellent for the urban landscape. Prune right after flowering, but only if necessary. May use as specimen, in groupings, borders, or hedge. Needs sun to part shade in USDA Zone 3-8.

• Perennial: Switchgrass (Panicum virgatum). Switchgrass is a native species to North America; it tolerates a wide range of soil and climatic conditions. Full sun is the best exposure for switchgrass, but it will grow in part shade. Switchgrass is a clumping warm-season grass. Showy flowers appear in July in airy panicles reaching 1 to 2 feet above the foliage. It works well in many types of gardens. Leaves can be deep green to gray-green. Common cultivars include Heavy Metal, Haenese Herms, Cloud Nine, Northwind, Shenandoah and Cheyenne Sky. USDA Zone 5-9.

• Tree: Desert willow (Chilopsis linearis). Desert-willow is not a willow at all and prefers dry, well-drained soils, compared to true willows, which grow along streams and ponds. Because Desert willow likes the hotter, drier conditions, it is an excellent choice for western Oklahoma and requires very well-drained soil. It grows as a small tree reaching 15-30 feet high and about 10 to 25 feet wide. Full sun in USDA Zone 7-9.

• Collecor’s Choice: Seven son flower (Heptacodium miconiodes). An upright, irregular, loose and open shrub growing 15 to 20 feet high. Leaves appear early in spring, and it is attractive and pest free. Flower buds form in early summer, but do not open until September. Individual flowers are tiny and white, but fragrant and attract butterflies. Seven son flower grows best in moist, well-drained acid soil. Full sun to part shade. USDA Zone 5-8.

Castor is a member of Garfield County Master Gardeners.