Spring is great for tree planting, and if you’re hunting for the next arboreal addition to your landscape, it’s a good time to think outside the box.
Many of us have seen the hazard of overplanting one species of tree–the Dutch Elm debacle of the 1970s and the current demise of ash trees in the midwest due to emerald ash borer should be evidence enough that while we can do well with fields and corn and soybeans, urban trees do best when diversified.
When people visit garden centers, their wish lists are often quite similar–fast growing, not messy and easy to grow. It might do us all good to add “and something my neighbors don’t have” to that list. So in the spirit of diversity, here are five suggestions of urban trees could be happy in your landscape for decades to come:
Katsura tree (Cercidiphyllum japonicum)–As with several successful shade trees, this beauty comes to us from Japan. The species katsura tree can reach 40 to 60 feet tall and 20 to 30 feet wide. The heart shaped leaves emerge with a reddish cast in the spring, morphing to an attractive bluish green. The tree puts on a gorgeous show of gold in the fall, and the fallen leaves have the aroma of brown sugar. The tree form is most often oval or pyramidal, though weeping forms that are smaller are also available. This is a hardy specimen, good to Zone 4 to 8, making it a great choice for Central Iowa.
Black Hills Spruce (Picea glauca var. densata)–The Black Hills Spruce, state tree of South Dakota, is a tough and resilient as one would need in the challenging range of weather that our neighbor to the northwest has. Hardy to Zone 2 (-40º F.), this denser foliaged cousin of the Colorado Blue Spruce can tolerate gravely soil, clay and sandy loam is quite drought resistant. Slow to moderate in growth rate, this evergreen can eventually reach 40 to 60 feet by 15 to 20 feet in width. The Black Hills spruce has an excellent form and doesn’t need pruning and also provides great shelter for birds.
‘Accolade’ Elm (Ulmus Morton ‘Accolade’)–(pictured in the top photo of this blog–from the Morton Arboretum in Lisle, IL) The Accolade Elm now available in nurseries is actually a clone of an 80 year old elm at Morton Arboretum from near Chicago–a cross that has thrived through decades of demise of the classic American Elm. This elm has been valued for its upright vase shape and graceful arching branches reminiscent of the original American elm. At a mature height of 75 feet and spread of 45 feet, this majestic shade tree is hardy to Zone 4 and a vigorous grower, slowing to about a foot and a half a year as a medium to mature tree.
Rising Sun Redbud (Cercis canidensis ‘JN2’)–Rising Sun redbud is a master class in how to take a well-loved plant and add two seasons of interest to its repertoire, then add a compact size and incredible soil tolerance for an encore. At 12 to 15 feet tall by 10 foot wide, this beauty is a crowd pleaser from the minute it’s brilliant pink flowers appear in early spring. The characteristic heart shaped leaves emerge as peach gold, maturing to green as they age, meaning that throughout the growing season, multi-colored leaves are the norm. Hardy from zones 5 to 8, this is a plant that belongs in your Central Iowa garden. The well-known sophisticated grey and rust bark will be with you all winter until the show begins anew in the next growing season.
Swamp White Oak (Quercus bicolor)--It is only fitting to round out any list of potential trees with an Iowa native, the Swamp White Oak. Sharing the lobed leaves of its other white oak cousins, Swamp White is one of the faster growing oaks (moderate) with a high tolerance for less than ideal soils. Add to that the ability to grow well in high moisture areas that would be the demise of lesser trees, and this is a shade tree that will grace the landscape for as long as 300 years. This a tall tree, ranging from 50 to 75 feet and growing 40 to 70 feet wide. Fruit set is usually every three to five years. The “bicolor” part of its name refers to its glossy green top and gray/white fuzzy underside.
So there’s your tree diversity bucket list–but don’t stop there. Take a walk through an area arboretum (e.g. Iowa Arboretum near Madrid, Brenton Arboretum near Dallas Center), and be amazed at the beauty of a diversely wooded landscape. Our state’s future citizens thank you for your foresight!
As always, don’t hesitate to contact Garden’s Grace to help you find a good tree selection for your landscape!
Blog written by Anne Larson, Des Moines area horticulturist and writer for Iowa Gardener Magazine, and a weekend associate with Miller Nursery.