Last post, I talked about how it may be time to reconsider the use of one large shade tree in our smaller residential yards. Since exotic pests and diseases are threatening our long lived trees, we should consider using multiple smaller shade trees from different plant families to reduce our risk of having a new pest eliminate all the shade in our yards.
Smaller Shade Trees to consider
Now, I will give you some possible smaller shade trees for you to use that you may have not considered. Different trees will serve different uses better. For instance, shading a house would be better accomplished by the elm or the maple, than the Amur Maackia. However, the Amur Maacki might be a great tree to shade a patio.
Note I don’t have any of these trees in my yard (yet!), but I’ve researched and seen them all in person. All the pictures were taken at the Chicago Botanic garden on May 19th, 2013. Since it is still spring, lots of these trees are just beginning to show their leaves, so expect them all to be much fuller after they are completely leafed out.
Since I’ve already incoherently rambled on for 196 words, this week I’ll just give you four (well really five) smaller shade trees to consider. There will be more to come next week.
AMERICAN YELLOWWOOD – A native smaller shade tree
Cladrastis kentukea (lutea)
- Height: 35 – 50′
- Width: 40 – 55′
- Shape: A naturally low branched tree with a rounded crown. This is not a tree you will stand under unless it is pruned extensively to allow it. This is more of a specimen in the lawn tree that will eventually cast shade.
- How fast does it grow: Medium (a little bit over 1’ per year)
- What zones is it hardy in: 4 – 8
- Native: Yes
Growing requirements: Yellowwood likes Full sun. This tree is also tolerant of both low and high pH soil. It should only be pruned in the summer as it bleeds excessive sap if pruned at other times.
Description: According to Dirrs Manual of Woody Landscape Plants, “the yellowwood is an excellent tree for flowers and foliage”. It’s most distinctive feature is its hanging clusters of white, fragrant, wisteria-like flowers. The tree may not bloom every year, but its bright green clean foliage and rounded form of this tree would make it worthwhile even if it never blooms. It can take the tree a long time to begin blooming (over a decade), so don’t plant it if it’s the flowers you’re after.
It has a thin, gray bark is similar to a beech. The yellowwood has few serious disease or insect problems, although it is susceptible to Verticillium wilt (like maples). It has an excellent, golden-yellow fall color most years, although its quality may vary year to year.
Frontier Elm – A smaller shade tree that echoes the past
- Height: 30 – 40′
- Width: 30′
- Shape: Handsome classic elm vase-shaped form
- How fast does it grow: fast (2’ or more a year)
- What zones is it hardy in: 5-8
- Native: No
Growing requirements: Tolerant of urban conditions, drought, poor soil, and compaction. Basically it is a tough tree.
Description: The days of the American elm lining city streets across the country may be over due to Dutch elm disease (DED), but plant breeders have been working to bring the elm back. To do this they have been cross breeding various elms to try and get a tree with the classic American elm shape but resistant to DED.
This is one of the better smaller ones they have come up with. Frontier elm is a moderate sized shade tree with a stiff rounded crown. It’s small leaves and reddish-purple fall color (unusual for an elm) comes from its lacebark elm parentage. Frontier elm is a US national Arboretum introduction. It shows a high level of tolerance to Dutch elm disease and elm yellows with a moderate resistance to elm leaf beetle. The Honey locust I planted several years ago should be getting very nervous right now.
Another smaller elm tree to consider if you are in a warmer zone is the Athena™ elm (Ulmus parvifolia ‘Emer I’). This tree has a beautiful broader than tall cloud shaped head. I have only seen this in pictures, but for a shade tree that only gets 40’ tall, it looks like a winner. If you are in Zone 6 or warmer, I would consider this tree. Some sources list it as hardy for zone 5, but nobody in my area sells it and it’s not at my local botanic gardens, so I don’t believe it.
- Height: 20-30′
- Width: 20-35′
- Shape: Round headed tree with upright spreading branches
- How fast it grows: Slow (less than 1 foot per year)
- What zones it is hardy in: 4-7
- Native: No
Growing requirements: Best grown in average moisture, well-drained soil in full sun to part shade. It would prefer full sun. Adapts to a wide range of soil conditions.
Description: Amur Maackia is an uncommon smaller shade tree that that would serve the needs of small urban yards well. It has an attractive branching form with an arching form. It also casts a nice dappled shade in the summer from its clean foliage. It is also unusual in that it has white flowers in the summer that smell like newly mown grass. Unfortunately it has virtually no fall color, although its branches form an attractive form in the winter.
- Height: 20-35′
- Width: 20-35′
- Shape: Rounded to broad rounded
- How fast it grows: Slow (grows about 1 foot per year)
- What zones it is hardy in: 5-8
- Native: No (unless you are one of my readers from Europe!)
Growing requirements: Full sun to part shade, in a moist, well-drained soil. Can tolerate some dryness, alkaline soils and compaction. It is also pollution tolerant (thus good for street tree use). Avoid pruning in early spring.
Description: The hedge maple is an excellent small lawn or street tree due to its low height. It tolerates pruning well and is commonly used in Europe to form large hedges (given its name). It usually turns a yellow fall color, but it is not as consistently nice as sugar or red maples. It currently has no serious insect or disease problems. Overall a nice compact version of the classic “MAPLE TREE” we often associate with shade trees, however with less showy fall color.
The hedge maple is a little bit hard to find, but if you call around you should be able to find in most areas.
So there are 4 (or 5 if you include the 2nd elm) smaller shade trees for you to consider when looking to create the shade that every garden sanctuary requires. Next post, I’ll give you some more to consider including more native trees.