Proven plants: 4 selections perfect for Oklahoma’s growing season and conditions

From rookies to seasoned gardeners, Oklahoma gardening can be a challenge for many of us. Fortunately, there are folks out there to help us locate plants, shrubs and trees that not only survive our challenging climate, but ones that actually thrive. Each year, horticulturists from around the state choose plants for the Oklahoma Proven program that are appropriate for Oklahoma landscapes. Now in its 24th consecutive year, the Oklahoma Proven program has chosen a tree, shrub, perennial and annual that have been proven to grow well in Oklahoma’s diverse climate.

Tree: Trident Maple (Acer buergerianum) — a small, slow-growing, deciduous tree, reaching 20-25 feet tall. It’s easily grown in average to medium moisture and well-drained soil. While it prefers full sun, it can be placed in partly shaded areas of the landscape. It can tolerate some drought as well as soil compaction and air pollution. Leaves are glossy green on top and pale green underneath. This tree features flaky bark that reveals an orange-brown inner bark on mature trunks.

Shrub: Winterberry Holly (Ilex verticillate) (dwarf cultivars: Little Goblin, Berry Poppins, Red Sprite) — a deciduous holly that doesn’t feature the sharp teeth on the leaves commonly found on other hollies. Bright red berries remain on the branches throughout the winter, adding a splash of color in the landscape. Winterberry is a globular, medium-sized shrub that grows to 10-20 feet tall. The dwarf cultivars that have been developed are perfect for those with limited outdoor space.

Perennial: Turk’s Cap (Malvaviscus arboreus var. drummondii) — has bright red flowers resembling a hibiscus flower that never fully opens. The overlapping petals form a loose tube that resembles a Turkish hat. These flowers appear later in the summer heat and early fall. While a good ornamental for shady landscapes, it can be adapted to thrive in full sun and heavy soil. The hotter Oklahoma sun can cause the leaves to become rougher, smaller, darker and puckered. However, once established, it is very drought tolerant. As a bonus, hummingbirds, butterflies, moths and other insects benefit from the plant’s nectar.

Annual: Cape Plumbago (Plumbago auriculata) — a weak-stemmed perennial evergreen shrub. While it can grow 7 feet tall and 8-10 feet wide in its native habitat, it is treated as an annual in Oklahoma where it generally reaches only 2-4 feet high and wide each season. It is a great choice for patios and decks as it can be grown in containers. This plant is kept compact in the landscape by periodic pruning. Hard pruning will encourage new growth for the coming season. It can overwinter indoors. It grows best in organically rich, fertile and well-drained soil in full sun to part shade. If planting in the landscape, select a spot that is protected from strong winds. While it thrives in consistently moist soils, established plants are moderately drought tolerant.

Visit oklahomaproven.org to see more information about the 2023 selections along with photographs from collections over the past 24 years.

Thank you to Tulsa County Master Gardeners for their expertise. Allen Robinson has been a Master Gardener since 2010.