by Jan Cashman

In the heat of the summer, a shade tree strategically planted on the west side of your house can keep your house a lot cooler. But which tree would be the best to plant? The only native trees that grow tall enough to provide some shade are quaking aspen and cottonwoods. However, there are many shade trees introduced from other parts of the U.S. and the world that will grow well here. A favorite of ours is the linden.

American (Tilia Americana) and littleleaf (Tilia cordata) are two species of linden that are available here.American linden has large, heart-shaped leaves, and is native to North America from Minnesota north into Canada and east to the Atlantic coast.My father, a Minnesotan, called this tree ‘Basswood’.In researching the common name, ‘basswood’, I learned that Native Americans used the fibers of the tree for sewing or ‘basting’, and over time, the name evolved to basswood.

Little leaf lindens, shorter than the American linden with smaller leaves, are native to most of Europe.Europeans called them ‘Lime trees’ although they are not related to the citrus, lime.The common name ‘Linden’ evolved from the word ‘lime’.Littleleaf linden is the national tree of the Czech Republic. It was planted on avenues in Europe in the 17th and 18th centuries; one famous example is Unter den Linden in Berlin.Linden’s flowers were a traditional herbal remedy considered to be of value for many ailments.The wood of littleleaf linden is used for refined woodcarvings because of its density.

There are many reasons why lindens make exceptional shade trees:*They are relatively disease and insect free.*They have a symmetrical, pyramidal shape. * They are long-lived.*They do well in poor soils and are somewhat tolerant of alkaline soils. * They have fragrant, yellow flowers in mid-summer. (Supposedly, both the flowers and young leaves are edible.)*Their shape and bark color makes them attractive in the winter.

Another important reason to plant lindens, or any other variety of shade tree not so commonly planted here, is to diversify our urban forest.There is a danger of planting too many of the same tree.Years ago, Midwestern communities like Minneapolis lost most of their urban forest to Dutch elm disease. Today, our green ash, the most commonly planted shade tree in Bozeman, are threatened by the emerald ash borer, an insect devastating to ash, introduced into Michigan from Asia in 2002, that today has made its way west as far as Minnesota.

There are many improved selections of American and littleleaf lindens, selected mostly for their shape and symmetry.‘Boulevard’ is a narrow, pyramidal selection of American linden.‘Frontyard’ is a dense, symmetrical American linden.At Cashman Nursery, we sold the American linden called ‘Redmond’ years ago, but don’t sell them anymore because many Redmond lindens here died due to winter injury.‘Greenspire,’ the most commonly planted selection of littleleaf linden, has a perfectly straight trunk and leathery, dark green leaves.

Although lindens have many pluses, they are not the perfect tree for everyone.They grow rapidly in more humid climates that have a longer growing season, but here they grow slowly.And they do not thrive in some of our higher elevations or harsher outlying areas.If you live west of Belgrade, or up Bridger Canyon, a linden might not be the best tree for you.Where ever you live, think about planting a tree to shade your house and keep it cooler.When deciding on which tree to plant, consider a beautiful, symmetrical linden.