It is not always easy to decide what plants to use in your garden and landscape, especially if you have limited space, so Oklahoma State University's “Oklahoma Proven” program is designed to help you do just that.

Oklahoma Proven is a plant evaluation and marketing program designed to help consumers select the best plants for Oklahoma gardens.

It can be so frustrating to spend money, time and effort on a garden or landscape plant only to have it fail. The goal of the Oklahoma Proven program is to promote plants that are tolerant of the varied and difficult environmental conditions found throughout Oklahoma. By using well-adapted plants, you will have more success with your plantings. And, since Oklahoma Proven plants generally are pest free and adapted to our climate, you also will be creating an easier to manage and more environmentally friendly outdoor space.

Although there are many plants suited for use in Oklahoma, the Oklahoma Proven selections are some wonderful choices. To see all the plants recommended by this program for the past 21 years, go to www.oklahomaproven.org/. You even can search by plant category for your specific needs.

Here is a look at the 2020 Oklahoma Proven selections.

The tree selection this year is the hornbeam (Carpinus species). The genus Carpinus includes the both the native C. caroliniana, American hornbeam and C. retusus, the common or European hornbeam.

American hornbeam is a slow-growing, understory tree with an attractive globular form that typically grows 20 to 35 feet tall. The European hornbeam needs little pruning when grown as a tree but also can be grown as a hedge and will take a hard pruning. If not heavily pruned, it is a medium-size tree that reaches 40 to 60 feet tall with a pyramidal to oval-rounded crown.

Hornbeam will take full sun or light shade, prefers a well-drained soil and tolerates medium moisture. Leaves are dark green and can produce pretty fall shades of yellow, orange and red. The tree trunks have smooth gray bark and distinctive fluting. You can find upright, columnar forms as well.

The Oklahoma Proven 2020 shrub selection is the red yucca (Hesperaloe parviflora). Red yucca is the common name of this plant, but it actually is not a yucca, it is instead a member of the century plant family (Agavaceae).

This drought-tolerant shrub produces soft, yucca-like, evergreen leaves, 2 to 3 feet in length, crowded on the perennial’s short, woody base. The flower stalk rises 5 feet and bears showy, coral-colored, tubular flowers on arching, wand-like, pink stems. This plant is a full sun lover which is hardy to Zone 5 and likes dry soils with excellent drainage.

This year’s Oklahoma Proven perennial is golden variegated sweet flag (Acorus gramineus ‘Ogon’). This plant is native to wetland areas in Asia. "Ogon" is a dwarf variety that features iris-like tufts of narrow, grasslike, variegated leaf blades (6 to 12 inches tall and 1/4 inch wide), which are striped with yellow and green but primarily appear as yellow.

Sweet flag is easily grown in average, medium to wet soils in full sun to part shade and performs well in both boggy conditions and consistently moist garden soils, so if you have one of those “too wet” locations in your landscape, it would be ideal. Sweet flag will appreciate some relief from hot summer sun like afternoon shade or filtered sun. The foliage is sweetly fragrant when bruised (hence the common name of sweet flag) and hardy in USDA Zones 5-9.

The annual chosen for 2020 is improved cultivars of Brazilian verbena (Verbena bonariensis), commonly called Brazilian vervain or verbena-on-a-stick. Brazilian verbena is a rapid-growing, clump-forming tender perennial that will take full sun to part shade It prefers good drainage but also will perform in poor soils. Plants typically form a 1-foot-tall basal clump of dark green leaves from which rise erect, slender branching, stems to 3.5 inches tall bearing clusters (to 2 inches across) of tiny rose-violet flowers.

Although Brazilian verbena is a tender perennial, it often grows as an annual in Oklahoma. If sited in sheltered locations with southern exposures, plants can survive mild winters. Even if plants do not survive winter, they often remain in gardens for several years through self-seeding. This species is very heat- and drought-resistant and makes a great cut flower, which also attracts butterflies and hummingbirds. Look for the improved cultivars, including Little One, Lollipop and Meteor Shower.

The Oklahoma Proven selections program can help you make choices for successful and attractive plantings in your landscape and gardens!

Email Julia Laughlin, Oklahoma County Extension horticulture educator, at julia.laughlin@okstate.edu.