Selections for 2018
Oklahoma Proven is a plant promotion program coordinated by faculty in the Department of Horticulture and Landscape Architecture at Oklahoma State University. The goal of the program is to recommend plants well-adapted for use across Oklahoma.
Tree for 2018
Zelkova serrata is a deciduous, tree with a vase-shaped habit that typically grows 50-80 feet tall and most often occurs in rich, moist woods and hillsides and moist stream banks. It is noted for its graceful shape, clean foliage, attractive bark and resistance to Dutch elm disease. Zelkova is often substituted for American elm (Ulmus americana) because of its resistance to Dutch elm disease. Cultivars from the Chinese cousin are also available.
Some notable cultivars: ‘Schmidtlow’ Wireless® (25’ high and 35’ wide); ‘Ogon’ (‘Bright Park’) (golden yellow leaves, coral stems); ‘Musashino’ (narrow upright 45’ high, but only 20’ wide); and ‘JFS-KW1’ City Sprite™ (compact, dense, semi-dwarf 25’ high and 20’ wide).
- Exposure: Full sun or light shade
- Soil: Tolerates wide variety of soils
- Hardiness: USDA Zone 5-8
Shrub for 2018
‘Little Volcano’ and ‘Gibraltar’
Lespedeza thunbergii subsp. thunbergii
Bush Clovers are hardy semi-woody, deciduous shrubs reaching 4 to 6 feet high and at least as wide with arching stems. In harsh winters it can die to the ground, but quickly comes back the following spring. Late winter, early spring pruning may be necessary to rejuvenate the plant. Flowers develop on new wood and are rosy-purple in late summer to early fall, which completely cover the plant. Bush Clovers perform well in sandy, infertile soil and are very drought tolerant once established; ideal drainage is essential.
‘Little Volcano’, a selection from Japan, is more upright with dark green foliage and red-purple flowers. Foliage turns golden after bloom in the fall. ‘Gibraltar’, found at the Gibraltar estate in Wilmington, DE, is a spectacular selection with long, arching stems also covered in rosy-purple flowers from late summer to early fall.
- Exposure: Sun to part shade
- Soil: tolerates poor, infertile soil; excellent drainage is essential
- Hardiness: USDA Zone 6-10.
Perennial for 2018
Indian pink, also called woodland pinkroot and pinkroot, is a native species to the Southeastern U.S. It is an excellent plant for shady gardens. Indian pink is an upright, multi-stemmed clump forming perennial 1-2 feet tall and 1 ½ feet wide with bright, glossy green leaves. Numerous flowers appear in late spring/early summer and are tubular, deep red with a contrasting yellow throat that flares at the tip to form five pointed lobes (a yellow star). Indian Pink grows in part shade to full shade in moist soils, but does really well in full sun and is quite drought tolerant once established.
Use Indian pink in a woodland garden, perennial border, rain garden, or native garden. Hummingbirds and butterflies are attracted to the beautiful, tubular flowers.
- Exposure: Sun, part shade
- Soil: Moist or dry soils
- Hardiness: USDA Zone 5-9
Annual for 2018
Supertunia® Vista Bubblegum®
Supertunia Vista Bubblegum is a vigorous petunia that requires very little care once established. Unlike some other petunias Vista Bubblegum is a self-deadheading variety that blooms continuously until the first killing frosts. With its bright bubblegum pink flowers Vista Bubblegum is a mounding, trailing form to 18-24 inches high and just as wide that looks spectacular spilling over the edge of a container or retaining wall or spreading out in a flower bed.
For the most vigorous plants fertilize them with a slow release fertilizer at planting and then follow up throughout the summer with a water soluble fertilizer applied when watering. Even though no dead-heading is needed, Vista Bubblegum responds well to a light trimming in early July.
- Exposure: Full sun to part shade
- Soil: Moist, well-drained soil
- Hardiness: Use as an annual