Extension

Gardeners may not have all of their holiday decorations packed away in tubs and returned to the attic, but with the start of a new year, it’s the perfect time to start thinking about gardening season.

 

It’s no secret that Oklahoma’s diverse growing conditions can make gardening challenging. Fortunately, a program developed by horticulturists at Oklahoma State University has been guiding gardeners since 1999. The yearly Oklahoma Proven plant selections include a tree, shrub, perennial and annual that have been proven to grow well across the state. This year’s selections include:

 

Tree: River Birch

This tree is a large shade tree native to the eastern half of the U.S. and grows along riverbanks, streams, and floodplains. A vigorous, fast-growing tree, it thrives in USDA Zones 4-9, is tolerant of flooding and can withstand short-term drought. It reaches about 40-70 feet tall and just as wide. The papery, exfoliating bark reveals colors ranging from salmon-pink to reddish-brown and white, which can add visual interest to the landscape. Foliage is bright green in the summer and bright yellow in the fall. River birch prefers moist, acidic soil but tolerates clay soils. This tree also attracts game birds, insect pollinators, small mammals and songbirds. River birch doesn’t have serious insect or disease problems.

 

Shrub: Japanese Aucuba/Japanese Laurel

A beautiful broadleaf evergreen, the Japanese aucuba grows to about 6 to 10 feet high with an equal or slightly greater spread. The leaves are bright to dark green, but the more popular forms are variegated types with varying amounts of creamy white or more commonly yellow splashes or spotting on the leaves. Tolerant of heavy shade, Japanese aucuba grows well in average garden soil with medium moisture, but it is tolerant of clay and dry soils. Japanese aucubas have few pest problems, but root rot can occur in poorly drained or overly wet soils. Gardeners may see some dieback during frigid winters, but the plants typically recover quickly. The Japanese aucuba is versatile, as it can be grown as a hedge, screen or background, as well as in planters and containers.

 

Perennial: False Indigo/Wild Indigo

This native perennial produces attractive trifoliate leaves that range in color from yellow-green, green, blue-green to gray-green. It can grow 2 to 4 feet high, and spikes of colorful flowers appear in the spring and early summer. Breeders have done amazing work with various species of false indigo, resulting in varieties that are more compact with sturdy stems, more floriferous and have an array of colors. Flower colors of these new hybrids include bright blue, lavender, purple, light pink, white, creamy white, bright and light yellow, and red. To add visual interest to the landscape, flowers appear in the spring, followed by inflated seed pods that turn charcoal black when ripe. The pods remain on the plant until winter. False indigo develops deep tap roots, making this plant drought-tolerant. It grows best in full sun but can survive in light shade; however, blooms will be reduced in number. Make sure the soil is well-drained.

 

Annual: Ornamental Pepper Cultivars

Peppers are easy to grow in Oklahoma, and they thrive in the heat. They add striking pops of color to the garden with their brightly colored fruits, which appear at the tips of the branches and last all season long. Fruits come in many colors, including red, purple, yellow and orange. They also vary in shape. Foliage can be bright green to almost black and may be variegated. Select a site that is well-drained and receives full sun exposure for optimal success. New cultivars are available that grow to approximately 10 to 20 inches in height and width. Their compact size makes them ideal for the annual flower bed, as well as a container plant for the patio. Fertilize regularly throughout the growing season. Ornamental pepper has no serious pest problems and requires little maintenance.