The other day I was teaching a group about native Illinois trees, and, of course, I was all excited because I was teaching about trees, which is my No. 1 passion. I know in the past I've talked about native plants and have mentioned my No. 1 favorite tree that just happens to be an Illinois native – Taxodium distichum Baldcypress. So I figured this time around I would focus on some small- and medium-sized native Illinois trees.
I want to preface this article with something that I feel is very important in regards to trees, and that's the idea of tree diversity. In the landscape and urban forest we want to diversify our trees to include both natives as well as non-native/non-invasive tree species so that we don't face the devastation our urban forests have suffered from Dutch Elm Disease and Emerald Ash Borer due to overplanting of the same genus or species. With that said, let's take a look at some interesting Illinois native trees.
American Hophornbeam (Osrya virginiana): This tree is considered one of Illinois' toughest native hardwoods resistant to a variety of insects and diseases. Reaching between 30 to 40 feet, it is a slow grower, growing less than a foot each year but worth the time. This tree is better suited for a larger area where it's drooping, horizontal branches have room to show off its beauty. Plant in part-shade to full sun in well-drained soils in the spring to allow it time to establish in the soil.
Carolina Silverbell (Halesia Carolina): This is considered a medium sized tree reaching between 30 to 40 feet tall and providing white flowers in the spring time and yellow leaf color in the fall, but it is known for dropping leaves early. Make sure to plant this tree in the spring to allow time for it to establish in the soil, and it will even tolerate some shade. A slightly acidic part-shade site in moist, well-drained soils is the perfect location for Carolina Silverbell.
Downy Serviceberry (Amelanchier arborea): This tree has a number of different names including Juneberry, Shadbush and Servicetree. It produces a very tasty fruit, ripening early to mid-summer, for which you must be speedier than the birds to harvest or provide some level of protection to keep the birds from getting the fruit first. Downy Serviceberry can reach 15 to 25 feet tall and can grow either as a multitrunk or single stem tree that blooms white in the spring with yellow-orange to red fall color. This tree also is tolerant of poorly drained sites and black walnut.
Eastern Redbud (Cercis canadensis): How can you talk about native Illinois trees and not include the iconic Eastern Redbud? This small tree can reach 20 to 30 feet tall with available cultivars such as the Rising Sun only reaching 12 to 15 feet tall and provides peachy-tangerine colored leaves throughout the growing season or Forest Pansy with distinctive purple-red colored leaves all season. Both have the traditionally recognized flower color of the common Eastern Redbud but with a few spiced up features -- shorter height and interesting leaf color.
River Birch (Betula nigra): Did you know that River Birch is actually an Illinois native? This trees pushes the boundary of being considered a medium size tree (medium is usually up to about 50 feet) but can range anywhere from 40 to 70 feet, and there are cultivars available that are much shorter. Fox Valley River Birch (Betula nigra "Little King") only reaches 8 to 10 feet tall which is much smaller and more space friendly for small yards. River Birch are prized for their cinnamon colored exfoliating bark, providing wonderful winter interest in the landscape. As is implied in the name River Birch preferred moist well-drained soils, so avoid planting them on high and dry locations such as berms. For fun tree trivia the tallest River Birch on record is 145 feet tall.