Too hot for you? Think shade trees!
By Dawn Pettinelli - UConn Home & Garden Education Center
Featured Article - posted Wed., Jul. 24, 2013
On these hot summer days, the shade of a nearby tree seems most inviting. I - like many gardeners, I suspect - tend to gravitate toward the shadier parts of the yard to work as much as I can. I am especially bemoaning the loss of a large, overgrown, yellow delicious apple tree that was the shade in half of my ‘bird house’ garden bed. It came down in last year’s late October snowstorm and a number of plants are now struggling in the hot sun. Another tree will be planted this fall. You too may find yourself thinking about where a little more shade would be appreciated.
Before adding a tree to your landscape, consider what attributes you find desirable. Do you want a tree with a moderate to fast growth rate, or one that will grow very slowly? Also think about the tree’s ultimate height, site requirements, pest problems, fall foliage, flowers, value as wildlife cover and/or food source, growth habits, shape, and so on.
Native tree species are a good place to start. They are adapted to our region, so their success rate is pretty high, and seedlings are often free for the digging. Native tree species to consider include red maple, sugar maple, hickory, beech, black tupelo, oaks, sassafras, ironwood, ash, elms and birches. Most grow at a moderate pace and have adapted to our acidic soils. They also support a tremendous amount of native wildlife – from turkeys to butterflies, with a few squirrels thrown in! The maples, sassafras, tupelo and red oaks have notable fall foliage as well.
Yellow buckeye (Aesculus flava) is native south of New England yet perfectly hardy here. Leaves resemble the common horse chestnut, but this species isn’t as prone to leaf diseases. Panicles of yellow blossoms appear in May, and come fall, leaves turn an attractive pumpkin color. Fruits are smooth-shelled, unlike its spiny relatives, and at maturity the yellow buckeye reaches 60 to 75 feet. Red horse chestnuts (A. x carnea) are also quite attractive in bloom, reach 40 feet in height, but are a bit messy with spiny fruits.
Most species of magnolia are grown for their flowers, but the cucumber magnolia (M. acuminata) has large, heart-shaped leaves and grows from 50 to 80 feet tall. Fuzzy white buds open to yellowish-green blossoms which mature into 2- to 3-inch cucumber-shaped fruits, hence the name. Fast-growing cucumber magnolias prefer a deep, moist soil with a near-neutral pH, so around here that means regular additions of limestone.
Two of my favorites, if you are in the market for a large tree, are the tulip tree (Liriodendron tulipfera) and yellowwood (Cladrastis kentukea). Tulip trees can grow up to 150 feet tall. They have bright green, tulip-shaped leaves that turn a delightful gold in the fall. Their flowers are subtle but breath-taking. Two- to 3-inch tulip-shaped blooms have yellow-green petals with an orange inner base. The bark is attractive, too.
I planted a yellowwood in my ‘white garden.’ The name stems from the color of the heartwood – a bright yellow. The inner portion of the roots is also a distinct yellow. Pinnately compound leaves are bright green, with maybe a touch of blue. Flowers are white and resemble wisteria blossoms appearing in early June. I love this tree species, and there is an incredible mature specimen on the UMass campus. I used to sit under it and admire it. The only problem with yellowwoods, which I discovered after the October snowstorm, is that they have narrow branch angles and they can split pretty easily when fully-leaved branches are weighed down by heavy snows.
Vase-shaped elm trees with their pendulous branches are favorite nesting sites for Baltimore orioles. Fervent breeders have been working for years to create Dutch elm disease-resistant elms. ‘Jefferson,’ ‘Princeton’ and ‘Valley Forge’ are three cultivars noted for their resistance to this disease. While not known for their fall foliage or flowers, elms support over 100 species of wildlife, and if you have the room for these massive trees, do consider them. Plans are underway to plant an elm where my yellow delicious apple once proudly stood. Chinese elms (Ulmus parviflora) are graceful, round-headed trees with branches becoming more pendulous with age. This species is quite adaptable, reaches 40 to 50 feet in height, and the back is an interesting mottled combination of grey, green, orange and brown.
Large, sunny expanses can be home to a grouping of shade trees. Tree species can be mixed or stick with one variety if you prefer. One possibility is a small grove of pine trees. Fast-growing eastern white pine (Pinus strobus) is a good choice, rising to 80 feet or more. Smaller pine species maturing at 60 feet or less include the Austrian pine (P. nigra), Japanese red pine (P. densiflora) or Scots pine (P. sylvestris).
Now is a great time to check out various tree species and discover the best fit for your yard. One local resource is the UConn Plant Database (http://www.hort.uconn.edu/plants/). One can look up plants by common or local names and also by desired traits. Wait until September and the return of cooler temperatures and, hopefully, more rainfall to plant. If you have questions about shade tree selection or on other indoor or outdoor gardening topics, call the UConn Home & Garden Education Center, toll-free, at 877-486-6271, visit www.ladybug.uconn.edu, or contact your local Cooperative Extension Center.