Christopher Starbuck, Ph.D., is a horticulturist, teaches a course on Woody Ornamental Plants and does applied research on stress management for landscape plants.

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Diversify your Landscape
by Christopher Starbuck    


       ‘Prairifire’ crabapple has spectacular pinkish-red flowers and excellent disease resistance.

Don’t just plant something because all your neighbors have that plant. Think about diversity, and think outside the box. Here are some underused plants that might be better choices than the old standbys.

Making better choices for trees and shrubs

Deciding which trees and shrubs to plant to create an aesthetically pleasing and functional landscape can be daunting. Too often, we tire of the quest for something different and end up planting what’s popular and readily available. Don’t give up! A little mental effort applied to plant selection can make your landscape infinitely more interesting than one mindlessly planted with generics. Also, increasing diversity reduces the risk of disastrous losses from pest outbreaks.

Following is a short list of trees and shrubs commonly planted for various purposes with possible alternatives. The author’s prejudices are readily evident. The alternatives tend to be less tidy-looking than the old standbys, but with some features that I find interesting or attractive.

 


Acer miyabei ‘Morton’.


Blackgum is a native with reddish new growth and eye-popping fall color.



Winterberry  


Black Hills spruce   


Betula nigra ‘Little King’  


Viburnum Cardinal Candy®

Flowering Tree

Cultivars of ornamental pear (Pyrus calleryana) are by far the most commonly planted flowering trees in Midwest landscapes. They are uniform in size and shape, spectacular in bloom and have beautiful glossy summer foliage. They are however, subject to fire blight and storm damage. They also produce viable seed, which is spread by birds to natural areas where seedlings shade out native species. There are many cultivars of crabapple that could be substituted for ornamental pear. While crabs are less symmetrical than the pears, they are equally as spectacular in bloom (and smell much better). Most produce attractive fruit, the seeds of which do not sprout in natural areas like those of Callery pears. Nearly all modern crab cultivars have excellent disease resistance. ‘Prairifire’ has a rounded form and grows to 20 feet with bright, pinkish-red flowers. ‘Adirondack’ is an upright cultivar, growing to 18 feet, with pure white flowers.

 

Shade Tree

Cultivars of red maple are commonly used as shade trees because they grow fast and have dependable red fall color. State Street™ (Acer miyabei ‘Morton’) is a fast growing, 40-foot, densely branched upright maple with a yellow fall color. It is heat tolerant and less subject to borer injury and problems due to high soil pH than red maple. If you think in the long term, consider our native swamp white oak (Quercus bicolor). While it might look a bit coarse for the first 10 years, this tree grows fairly fast, reaching 60 feet. It tolerates both wet soil and drought.

 

Colored Foliage

For some reason, many people are fascinated by plants with purple summer foliage. Purple leaf plum (Prunus cerasifera), is an old standby for summer purple. Unfortunately, it is short lived due to its susceptibility to winter injury, borers, tent caterpillars and many other problems. If you can switch to red, consider Red Rage™ blackgum (Nyssa sylvatica ‘Haymanred’) as an alternative. New growth is bright red in spring and the fall color is an incredibly intense red. Blackgum grows much better in wet soils than purple leaf plum.

 

Hedge

Boxwood is usually the first plant that most people think of for an evergreen hedge. How about inkberry (Ilex glabra)? A dwarf cultivar like ‘Shamrock’ grows about 4 feet tall with glossy, dark green leaves, creating an interesting texture. While it is less formal looking than boxwood, it can be maintained as a hedge with less pruning. It is also not prone to the fungal canker diseases that often cause dieback of boxwoods.

 

Evergreen Tree

Blue spruce is popular as an evergreen tree because people tend to like its bluish foliage and the tidy form. However, fungal needle blight diseases have decimated blue spruces during the past several abnormally wet years. Although Black Hills spruce (Picea glauca ‘Densata’) is somewhat slower growing, less blue and less pyramidal than blue spruce, it is more adaptable to the extremes in moisture and temperature that we face in the Midwest and it is also less prone to fungal needle blights.

 

Specimen Tree

Weeping mulberries are commonly planted to create landscape interest. After a few years, they usually look like strange, shaggy mops. Fox Valley® birch (Betula nigra ‘Little King’) is a very dwarf (10 feet) river birch with a mounded form and stunning, exfoliating bark. This is a plant that will create interest in your landscape for many years with little maintenance.

 

Focal Point

With its tight, conical form and dense, deep green needles, Alberta spruce definitely catches the eye. If you want a different, but equally eye-catching look and have some room, consider weeping Nootka falsecypress (Chamaecyparis nootkatensis ‘Pendula’). This slow-growing evergreen eventually reaches 35 feet. It has rich, deep green foliage in flattened sprays that hang down gracefully from horizontal branches. It will grow in sun or part shade and is not plagued by mites as is Alberta spruce.

 

Flowering Shrub

With thousands of stunning plants to choose from, selecting flowering shrubs can be truly bewildering. Rose of Sharon is commonly planted because it is tough as nails and has large, profuse and cheery blooms in the heat of summer. Why not spread out seasonal interest by planting some viburnums. Cardinal Candy® (Viburnum dilatatum ‘Henneke’ ) is a good example of a shrub for all seasons. It has creamy, white flowers in spring, attractive summer foliage, fairly good wine fall color and brilliant red fruit persisting into early winter.

We all have our favorite plants. Some of the plants suggested here might seem strange or inappropriate, but I happen to like them. The point of this article is to encourage you to broaden your plant palette. Go to gardens, take notes on plants that strike your fancy and do some homework. Don’t be afraid to try something different. Some of your choices might not work, but you will learn a lot from trying them.

 

(From State-by-State Gardening November/December 2011. Photos courtesy of Christopher Starbuck.)

 

Posted: 12/28/11   RSS | Print

 

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