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Perennial

  • Prinz Heinrich Japanese Anemone - 2021 Anemone hupehensis var. japonica
    Prinz Heinrich Japanese Anemone
    2021 Anemone hupehensis var. japonica
  • Prinz Heinrich Japanese Anemone - 2021 Anemone hupehensis var. japonica
    Prinz Heinrich Japanese Anemone
    2021 Anemone hupehensis var. japonica
  • Golden Variegated Sweet Flag - 2020 Acorus gramineus ‘Ogon’
    Golden Variegated Sweet Flag
    2020 Acorus gramineus ‘Ogon’
  • Golden Variegated Sweet Flag - 2020 Acorus gramineus ‘Ogon’
    Golden Variegated Sweet Flag
    2020 Acorus gramineus ‘Ogon’
  • Rattlesnake Master - 2019 Eryngium yuccifolium
    Rattlesnake Master
    2019 Eryngium yuccifolium
  • Rattlesnake Master - 2019 Eryngium yuccifolium
    Rattlesnake Master
    2019 Eryngium yuccifolium
  • Indian pink - 2018 Spigelia marilandica
    Indian pink
    2018 Spigelia marilandica
  • Indian pink - 2018 Spigelia marilandica
    Indian pink
    2018 Spigelia marilandica
  • Milkweed - 2017 Asclepias
    Milkweed
    2017 Asclepias
  • Milkweed - 2017 Asclepias
    Milkweed
    2017 Asclepias
  • Milkweed - 2017 Asclepias
    Milkweed
    2017 Asclepias
  • Sedge - 2016 Carex species
    Sedge
    2016 Carex species
  • Sedge - 2016 Carex species
    Sedge
    2016 Carex species
  • Volcano Phlox - 2015 Phlox paniculata
    Volcano Phlox
    2015 Phlox paniculata
  • Switch Grass - 2014 Panicum virgatum cultivars
    Switch Grass
    2014 Panicum virgatum cultivars
  • ‘Walker’s Low’  Catmint  - 2013 Nepeta x faassenii
    ‘Walker’s Low’ Catmint
    2013 Nepeta x faassenii
  • Arkansas Bluestar - 2012 Amsonia hubrichtii
    Arkansas Bluestar
    2012 Amsonia hubrichtii
  • Arkansas Bluestar - 2012 Amsonia hubrichtii
    Arkansas Bluestar
    2012 Amsonia hubrichtii
  • Arkansas Bluestar - 2012 Amsonia hubrichtii
    Arkansas Bluestar
    2012 Amsonia hubrichtii
  • Giant Coneflower - 2011 Rudbeckia maxima
    Giant Coneflower
    2011 Rudbeckia maxima
  • Giant Coneflower - 2011 Rudbeckia maxima
    Giant Coneflower
    2011 Rudbeckia maxima
  • Toad Lily - 2010 Tricyrtis hirta
    Toad Lily
    2010 Tricyrtis hirta
  • Mexican Feather Grass - 2009 Nassella tenuissima
    Mexican Feather Grass
    2009 Nassella tenuissima
  • Hellebore - 2008 Helleborus
    Hellebore
    2008 Helleborus
  • Evening Primrose - 2007 Oenothera macrocarpa
    Evening Primrose
    2007 Oenothera macrocarpa
  • 'Golden Jubilee' Anise Hyssop - 2006 Agastache foeniculum 'Golden Jubilee'
    'Golden Jubilee' Anise Hyssop
    2006 Agastache foeniculum 'Golden Jubilee'
  • Perennial Plumbago - 2005 Ceratostigma plumbaginoides
    Perennial Plumbago
    2005 Ceratostigma plumbaginoides
  • Autumn Sage - 2004 Salvia greggii 'Pink Perfernce'
    Autumn Sage
    2004 Salvia greggii 'Pink Perfernce'
  • Japanese Painted Fern - 2003 Athyrium nipponicum
    Japanese Painted Fern
    2003 Athyrium nipponicum
  • 'Magnus' Purple Coneflower - 2002 Echinacea purpurea 'Magnus'
    'Magnus' Purple Coneflower
    2002 Echinacea purpurea 'Magnus'
  • 'Siskiyou Pink' Gaura - 2001 Gaura lindheimeri 'Siskiyou Pink'
    'Siskiyou Pink' Gaura
    2001 Gaura lindheimeri 'Siskiyou Pink'
  • 'Homestead Purple' Verbena - 2000 Verbena canadensis 'Homestead Purple'
    'Homestead Purple' Verbena
    2000 Verbena canadensis 'Homestead Purple'
  • 'Powis Castle' - 1999 Artemisia 'Powis Castle'
    'Powis Castle'
    1999 Artemisia 'Powis Castle'


Oklaoma Proven! logo.jpgOklahoma 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 2020

Hornbeam

Carpinus species

The genus Carpinus includes the native C. caroliniana, American hornbeam and C. betulus, the common or European hornbeam, both common in the trade.

American hornbeam is a slow-growing, understory tree with an attractive globular form. It typically grows 20-35' tall. The European hornbeam grows in full sun to part shade and needs little pruning when grown as a tree, but responds well to hard pruning if grown as a hedge; it is a medium-sized, tree that grows 40-60’ tall with a pyramidal to oval-rounded crown.

Both trees produce flowers as separate male and female catkins, with the female catkins giving way to distinctive clusters of winged nutlets. Leaves are dark green and can produce respectable shades of yellow, orange and red in fall. Trunks have smooth gray bark and distinctive muscle-like fluting. Upright, columnar forms are available.

 

  • Exposure: Full sun or light shade
  • Soil: Tolerates medium moisture, well-drained soils
  • Hardiness: USDA Zone 3-9 (4-8)
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    Tree for 2019

    'Vanderwolf's Pyramid', Limber Pine

    Pinus flexilis

    ‘Vanderwolf’s Pyramid’ limber pine is an evergreen tree with a pyramidal habit that typically grows 20-30 feet tall and about 10-15 feet wide. The specific epithet and common name is in reference to the flexible (limber) branchlets/twigs. ‘Vanderwolf’s Pyramid’ is noted for its closely spaced, twisted, silvery blue green needles. Limber pine is generally considered to be an adaptable, low-maintenance tree with few problems. Limber pine is native to North America and is considered resistant to pine wilt disease.

    • Exposure: Full sun or light shade
    • Soil: Tolerates wide variety
    • Hardiness: USDA Zone 4-7

     

     

     

    Tree for 2018

    Japanese Zelkova

    Zelkova species

    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

     

     

     

    Tree for 2017

    Fringetree

    Chionanthus cultivars

    Chionanthus virginicus is a deciduous, native shrub or small tree with a spreading, rounded habit that typically grows 12-20 feet tall and most often occurs in rich, moist woods and hillsides and moist stream banks. The common name fringetree refers to the slightly fragrant, spring flowers which feature airy, terminal, drooping clusters of fringe-like, creamy white petals. Fringetrees are dioecious (separate male and female plants), but also may have perfect flowers on each plant. Male flowers are showier than female flowers. Plants with perfect or female flowers may give way to clusters of olive-like fruits which ripen to a dark, bluish black in late summer and are a food source for birds and wildlife. Cultivars from the Chinese cousin is also available.

    • Exposure: Full sun or light shade
    • Soil: Tolerates wide variety of soils
    • Hardiness: USDA Zone 5-8
    2017 Chionanthus cultivars

     

     

     

    Tree for 2016

    Escarpment Live Oak

    Quercus fusiformis

    Escarpment live oak is a smaller version of the coastal live oak (Q. virginiana) growing slowly to 20 to 40 feet high and about as wide with picturesquely gnarled branches and evergreen leaves. Escarpment live oak is native to southern Oklahoma through central and western Texas to northern Mexico, which means it is also more drought and cold tolerant than coastal live oak. Because of its slower growth it is a perfect long-lived shade tree for smaller, urban landscapes. Branches provide excellent nesting sites for birds and small mammals. Acorns are elongated and eaten by wildlife. It is also the larval host of the Hairstreak and Horace’s Duskywing butterflies.

    • Exposure: Full sun or light shade
    • Soil: Alkaline to slightly acid, well-drained soils
    • Hardiness: USDA Zone 6-10

     

     

     

     

    Tree for 2015

    Hedge Maple

    Acer campestre

    Hedge maple is a small to medium sized tree slowly growing to 25’ to 35’ high and wide. Because of its small size it is perfect for smaller, urban landscapes and even under utility lines. Hedge maple has beautiful green summer foliage that is free of ailments; fall color is yellow to yellow-green in color. Branches often develop very low to the ground providing excellent cover for wildlife, though it can easily be limbed up if desired. Hedge maple is really not too picky of soils; though it prefers rich, well-drained soil it grows well in compacted and alkaline soils. It also tolerates severe pruning and has often been used as a hedge, even walls, especially in Europe. Hedge maple is one of the tougher maples, which is underutilized in the U.S., has few problems, and is very urban tolerant. Golden leaf and variegated leaf forms are available.

    • Exposure: Full sun or light shade
    • Soil: Tolerates wide variety of soils
    • Hardiness: USDA Zone 5-8

     

     

     

    Tree for 2014

    Desert-willow cultivars

    Chilopsis linearis

    Desert-willow is not a willow at all, and prefers dry, well-drained soils, compared to true willows, which grow along streams and ponds; in fact, it will not tolerate heavy, wet soils. Because it likes the hotter, drier climates it is an excellent choice for western Oklahoma. Desert-willow grows as a small tree 15’-30’ high and 10’ to 25’ wide. It is a loose, gangly tree favored for its colorful, funnel-shaped flowers that put on their biggest show in early summer, and then bloom sporadically throughout the rest of summer. Flowers can be white, pink, rose, or lavender with purple markings inside and are sweetly fragrant. Foliage is a rich green in summer with no fall color, falling early to reveal the interesting branching structure. Several cultivars exist. Desert-willow makes a great patio or small specimen tree and attracts hummingbirds and other birds.

    • Exposure: Full sun
    • Soil: Dry, well-drained soils
    • Hardiness: USDA Zone 7-9

     

     

     

    Tree for 2013

    Winterberry Euonymus

    Euonymus bungeanus

    Winterberry euonymus is a large shrub to small tree with pendulous branches and light green foliage. Flowers are yellowish-green but not showy. Fruits are pinkish capsules which split open at maturity revealing an orange aril (fleshy seed covering). Fall color can be yellow to orange and red. Bark is green with a rough texture and is also quite attractive. Winterberry grows 15’-24’ high and just about as wide. It is very adaptable and quite drought tolerant. It is mostly resistant to scale insects that are common on other euonymus species. Winterberry makes a great patio or specimen tree.

    • Exposure: Full sun to part shade
    • Soil: Tolerates a wide range of soils
    • Hardiness: USDA Zone 4-7

     

     

     

    Tree for 2012

    Chinkapin Oak

    Quercus muehlenbergii

    A native oak growing throughout most of Oklahoma and eastward, chinkapin oak is a rather attractive shade tree that grows 40 to 50 feet high and wide in the landscape. The tree has a nice medium texture in summer and a medium-coarse texture in winter. Bark on stems and trunk develop into irregular blocky scales with age and is quite attractive. Leaves are a glossy, dark yellow-green in summer with varying fall color of yellow to orangish brown to brown. Chinkapin oak is adapted to various soils, even alkaline soils; and is quite drought resistant and tolerant of windswept sites.

    • Exposure: Full sun to part shade
    • Soil: Prefers well-drained soil
    • Hardiness: USDA Zone 5-9
    2012 Chinkapin Oak

     

     

     

    Tree for 2011

    American Elm Collection
    New Harmony, Princeton, and Valley Forge

    Ulmus americana

    With the release of improved, disease resistant American elms, they are once again in demand. ‘Valley Forge’, ‘New Harmony’, and ‘Princeton’ are a few of the cultivars available today. ‘Valley Forge’ is upright, arching, broadly vase-shaped with a full, dense canopy. ‘New Harmony’ develops into a broad vase-shaped crown with arching branches terminating in numerous slender, often drooping branchlets. ‘Princeton’ is also vase-shaped. American elms are adapted to a wide variety of soil conditions, tolerate deicing salts, air pollution, drought, and a range of soil pH. They have yellow fall color.

    • Exposure: Full sun to part shade
    • Soil: Prefers well-drained soil
    • Hardiness: USDA Zone 5-9

     

     

     

    Tree for 2010

    Indian Cherry

    Rhamnus caroliniana

    Indian Cherry is a small tree (or large, multi-stemmed shrub) to 20’ tall with a rounded to spreading canopy. It is native to the eastern, southeastern US making it more desirable over its European cousins. The foliage is dark, lustrous green all summer turning yellow to orange yellow in the fall. Probably its greatest asset is the colorful fruits that develop late summer/fall turning red and then to black as they mature. These beautiful, sweet fruit also attract several species of birds and can be used to make jams and jellies.

    • Exposure: Full sun to shade
    • Soil: Prefers well-drained soil
    • Hardiness: USDA Zone 5-9

     

     

     

    Tree for 2009

    Arizona Cypress

    Cupressus arizonica

    Arizona cypress is a drought tolerant, evergreen tree native to the southwestern United States. In the landscape it usually reaches a height of only 20’ to 25’ and 15’ wide. The foliage can be a gray-green but usually blue-foliage and recently yellow foliage forms are available in the trade. ‘Blue Ice’ and ‘Carolina Sapphire’ are common cultivars and ‘Cookes Peak’ is a selection from Cookes Peak, New Mexico with silvery-blue foliage and pyramidal form (see photograph). Arizona cypress require well-drained soil and thrive in hot, dry environments. As the tree ages, the bark exfoliates beautifully becoming mottled with patches of burnt orange and green.

    • Exposure: Full sun
    • Soil: Well-drained
    • Hardiness: USDA Zone 7

     

     

     

    Tree for 2008

    Bosnian Pine

    Pinus heldreichii

    Bosnian Pine is a slow-growing evergreen with a dense pyramidal form when young. It has the potential to grow to 70' tall in its native environment but is more likely to reach only 25 to 30' in the landscape. In the Pirin Mountains of Bulgaria there is a 70' tall Bosnian Pine estimated to be over 1300 years old! Young cones are purple and turn brown as they mature and the seed they produce is edible. Bosnian Pine prefers full sun and once established is quite tolerant of high pH soils and drought. It is also disease resistant and can be used in the landscape where an evergreen or pine is desired and space is limited.

    • Exposure: Full sun
    • Soil: Tolerant of dry and high pH soils
    • Hardiness: USDA Zone 6

     

     

     

    Tree for 2007

    Oklahoma Redbud

    Cercis canadensis var. texensis

    A cultivar of Oklahoma’s state tree, ‘Oklahoma’ was discovered in the Arbuckle Mountains and was selected for the incredible magenta flowers that cover the tree in early spring. When the flowers fade, heart-shaped leaves emerge with a beautiful glossy sheen. ‘Oklahoma’ Redbud can withstand full sun and their small size (15' – 25' high) makes them perfect for use under utility lines. They tolerate a wide range of conditions but do best on well-drained soils. ‘Oklahoma’ is one of the most beautiful native trees and is perfect for small yards needing a splash of color or grouped together where space allows.

    • Exposure: Full sun to part shade
    • Soil: Well-drained
    • Hardiness: USDA Zone 6

     

     

     

    Tree for 2006

    ‘Prairifire’ Crabapple

    Malus 'Prairfire'

    Few trees have as much year-round interest as the crabapple and few crabapples are as beautiful and disease resistant as ‘Prairifire’. ‘Prairifire’ starts the spring with a profusion of rose-pink flowers just as the leaves emerge. As summer progresses the leaves turn from purple-red to dark green and red fruit forms that persist well into the winter. The diseases that affect many crabapples don’t phase this tree and its rounded crown, which will not exceed 20' tall, makes it a perfect choice for planting under utility lines or in masses.

    • Exposure: Full sun
    • Soil: Well-drained
    • Hardiness: USDA Zone 4

     

     

     

    Tree for 2005

    Cedar Elm

    Ulmus crassifolia

    Cedar elm can thrive in almost any soil type, including the alkaline and heavy soils common in Oklahoma. It is one of the more disease resistant native elms, producing glossy green leaves in early spring that turn a muted yellow in the fall. Its form can vary from upright-oval to broadly horizontal and it generally matures around 60' tall. It can be distinguished from other elms by its rough-textured leaves, corky projections on young stems, and flowers and fruit produced in the fall.

    • Exposure: Full sun
    • Soil: Tolerates a wide range of conditions
    • Hardiness: USDA Zone 6

     

     

     

    Tree for 2004

    Shantung Maple

    Acer truncatum

    Shantung Maple is a drought tolerant small to medium-sized tree great for under power lines or in residential landscapes where there isn’t room for a large tree. It grows quickly but typically only to 30' high. The leaves are star-shaped and typically emerge with an attractive purple tinge. This Asian native can have excellent fall color ranging from yellow to orange or red.

    • Exposure: Full
    • Soil: Tolerates a wide range of conditions
    • Hardiness: USDA Zone 4

     

     

     

    Tree for 2003

    Kentucky Coffee Tree

    Gymnocladus dioica

    Kentucky Coffee Tree is an Oklahoma native growing to 60 feet tall. It is very heat and drought tolerant and does well on high pH soils. Although it has few branches when young, it matures to a majestic and beautiful tree with large seed pods adding winter interest.

    • Sun Exposure: Full
    • Soil: Tolerates a wide range of conditions including dry and alkaline soils
    • Hardiness: USDA Zone 4

     

     

     

    Tree for 2002

    Bur Oak

    Quercus macrocarpa

    Bur Oak is an Oklahoma native that can grow to 60 feet tall, with an even larger spread, and can tolerate drought, heavy soils, and high pH soils. Bur Oak can grow to be a majestic specimen and is an important wildlife species since many animals feed on its large acorns.

    • Sun Exposure: Full
    • Soil: Adapted to alkaline, sandy, and clay soils
    • Hardiness: USDA Zone 3

     

     

     

     

    Tree for 2001

    Shumard Oak

    Quercus shumardii

    Shumard Oak is an Oklahoma native plant that can grow to be over 100’ tall in the wild, but reaches 40 – 60’ in the landscape. Shumard Oak produces healthy green foliage even on alkaline soils, tolerates summer heat and drought, and transplants easily.

    • Sun Exposure: Full
    • Soil: Well-drained
    • Hardiness: USDA Zone 4

     

     

     

    Tree for 2000

    Bald Cypress

    Taxodium distichum

    This large Oklahoma native will lose its leaves in the fall after turning a russet or coppery-bronze and can easily grow to 70’ high with a 30’ spread. Tolerant of both wet and dry soils, Bald Cypress makes an outstanding specimen, street tree, or pond-side grove.

    • Sun exposure: Full
    • Soil: Well-drained to flood tolerant
    • Hardiness: USDA Zone 4

     

     

     

    Tree for 1999

    Chinese Pistache

    Pistacia chinensis

    Chinese pistache reaches a height of 30’ to 45’ with only a slightly smaller spread. Brilliant yellow leaves may grace the tree in autumn. Chinese pistache is a tough tree tolerant of drought, heat, and heavy soils.

    • Sun Exposure: Full
    • Soil: Tolerates a wide range of conditions including dry and alkaline soils
    • Hardiness: USDA Zone 6