Tree Selection

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Posted by justtracy | Posted in Gardening, Trees | Posted on 26-06-2012

Recently someone asked me about replacing a tree in their front yard and establishing a shrub bed underneath.  Careful consideration of the tree choice is important because a lot of very commonly sold trees  really do not like to share their root zone with other plants or even grass.

Most trees have shallow roots that spread out but don’t go very deep.  You will need to consider that whatever you plant under the tree is sharing water and nutrients with that tree. This requires more watering of the shrubs you put under the tree to get everybody established and during periods of drought.  It is best to find a tree that does not have a very shallow root system.

Stay away from Maples for this reason.  Also stay away from Ashe trees (also in the maple family) because of the emerald ash borer problem.   And also stay away form anything in the Black Walnut family because the roots emit a toxin that prevents other plants even grass from growing under or anywhere near them.  Oak trees have nice deep roots, but there is one caveat:  Deer love acorns. So you will attract deer to an oak tree and then they will eat your shrubs.

There is one more thing to consider about trees: some on the lists below are considered ‘messy’.  Kentucky Coffee tree produces huge pods that fall off each fall.  So when you go to a local garden center ask about how messy the tree is or what kind of seed pods or flowers does it produce.   Magnolias, Sweet Gums and Catalpas also are considered messy trees.

Here is a link to a pdf from the University of Minnesota Extension on Planting under Trees: http://www.extension.umn.edu/distribution/horticulture/components/8237ppt.pdf

Fine Gardening has a list of trees that tolerate underplanting better than others at http://www.finegardening.com/how-to/articles/planting-under-a-tree.aspx

Below is a list of trees that I would consider

Smaller Ornamental Trees: ServiceBerry (amelanchier), Hornbeam, Yellowwood,  Carolina Silverbell, Dogwoods, Redbuds, Hawthornes, CrabApples, Crape Myrtles (some can be very large)

Medium Trees: Katsura (love this tree), Thornless Honeylocust, Stewartia (beautiful bark)

Large Trees: Ironwood, Sourwood, European Mt Ash (not a true ash), Little Leaf Linden or Silver Linden

And then the shrubs for underneath…I would go to your local garden center and pick the tree first and then the shrubs.  Just let them know that is your plan. And then just be specific about what you want and they should know what they have to match that.  Here is some things to consider for shrubs:

Size: tell them you do not want to prune them and want them to stay a certain size.  Slow growing, dwarf shrubs would be a good choice.   Keep in mind the ultimate size of your tree and scale the shrubs down to that tree.  Large tree = larger shrubs; small ornamental tree = dwarf or low spreading shrubs.

Shrubs to avoid: barberries, burning bushes, eunoymous, (invasive, lots of pruning and pest problems)

 

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