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Ginko tree leaves

Oklahoma Proven 2022

3/22/22

Master Gardeners are often asked for plant recommendations. There are so many options and so many Master Gardeners that you will likely get a different answer from each Master Gardener because, let’s face it, we all have our favorites.

One source we like to refer those questions to is the Oklahoma Proven program. Oklahoma Proven is a program curated by Oklahoma State University in which various plants are tested and evaluated for their likelihood of success here in Oklahoma. Some plants look good in the catalogs or when we see them at the store, but the reality is, some of them just wont’s do that great in our growing conditions. The goal of the program is to help Oklahoma gardeners become successful in more environmentally friendly gardens.

Each year the program selects an annual, perennial, shrub, tree, and a Collector’s Choice Selection. Let’s talk about the selections for 2022.

This year’s tree is the Ginkgo Biloba, also known as the Maidenhair tree. One thing to love about the Ginkgo tree is the shape of their leaves. Each leaf has two lobes that have a somewhat leathery texture, is fan-shaped, and has parallel veins. Whenever I see one, it reminds me of something that might be found in the movie Avatar, but that’s probably just me. These leaves remain bright green throughout the summer but then you get a special showing of bright yellow as the leaves change color in the fall.

Ginkgo trees can grow to between 50 and 80 feet high and 30 to 40 feet wide. One of the great things about these trees is that they do well in full sun and will accommodate a little shade. They also tolerate a wide variety of soil conditions.

The shrub for 2022 is the Buttonbush aka Cephalanthus occidentalis. Buttonbush is native to Oklahoma and can be found bordering Oklahoma’s streams and lakes. This one fits in the medium to large shrub category as it grows to a height of between 5 to 12 feet with a width of 4 to 8 feet. This flowering shrub will put on white, fragrant flower between June and July. Some say these flower look like a pincushion. The flowers are attractors for hummingbirds, bees, butterflies, and a variety of other pollinator insects. When we say this plant can be found near lakes and streams, that tells us that it tolerates wet, swampy soils pretty well. Plant in full sun to part shade in moist or wet areas. It will not tolerate dry soil very well.

This year’s perennial is called Coral Bells. This one is native to North America with interesting foliage and bell-shaped flowers. Foliage is considered evergreen to semi-evergreen so they can provide year-round interest in your garden. Yes, these plants produce flowers, but it is the leaves that are the real point of interest. Some have marbled patterns, impressive veining, touches of silver, and then there are the ruffled edges of the leaves. But let’s not discount the flowers entirely as they prove themselves to be a favorite for butterflies and bees.

Coral bells prefer part shade but will do well in full sun if you keep them hydrated. The lighter the foliage, the better they will do with some shade. Darker varieties will be more tolerant of direct sun. This perennial is pretty drought tolerant once it gets established, but due to their shallow roots, they will still need supplemental water during dry periods.

Speaking of colorful leaves, this year’s annual is Plectranthus Scutellarioides, better known as Coleus. Coleus have typically been thought of as a shade plant, but new varieties are much more tolerant of the sun. Coleus will grow best in rich, moist, loose soil, so don’t let their soil dry out.

Coleus range in size from 6 inches to 3 feet in height, depending on the cultivar. They are considered a tender annual, meaning that they are likely done at our first frost. You can be successful growing them as an indoor houseplant, but they will need a lot of light.

Now on to the Collector’s Choice plant for 2022; Mexican Buckeye, aka Ungnadia speciosa. This one is a multi-stemmed, native shrub that can grow to a height of 15 to 30 feet and about 20 feet wide. Mexican Buckeye is native to central Texas, New Mexico, and Mexico. It is a fast grower and drought resistant.

Mexican Buckeye produces pink flowers that resemble redbud blossoms as it begins to leaf out in the spring. The leaves are initially a light bronze in color but turn pale green during the growing season. Bees and butterflies will appreciate their spring flowers while the seeds will be eaten by birds or other mammals.

If you are interested in looking into Oklahoma Proven plants from previous years, we have a link to the Oklahoma Proven webpage in the Hot Topics section of our website (www.tulsamastergardeners.org). See you in the garden!

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Photo: Paul Wray, Iowa State University, Bugwood.org