2015 April 22
Several people have asked me for shade-tree recommendations in the last month. This column will focus on deciduous trees that shade people and don’t gulp huge amounts of water. If you’re envisioning your family and friends enjoying the shade of a tree on a hot summer day, you don’t need a huge tree. Medium and even some small trees may be just the thing.
Smaller trees generally are easier to maintain – you won’t need to hire a cherry picker as frequently to deal with the tree canopy and you’ll probably have fewer leaves to rake. If you pick the right species, a smaller tree will require less water than a larger one. Also, you might consider planting a grouping of smaller trees rather than one huge tree.
When selecting a tree to sit under, I would choose one that has a straight trunk with smaller radiating branches. Over time, you will want to remove the lower temporary branches (those that grow out from the trunk at heights less than eight feet). A straight trunk will give the tree a more umbrella shape and allow for more sitting room than a tree that splits into multiple trunks lower to the ground.
My favorite medium sized trees (mature height of 40 ft. or less) that seem to be doing well in Alamosa include ‘Autumn Blaze’ Maple (Acer x freemanii), Shademaster Honeylocust (Gleditsia triacanthos inermis) and American Elm ‘New Horizon’ (Ulmus japonica x pumila).
We have maples in Zapata Park and along 6th St. by the railroad parking lot. They have beautiful red foliage in the fall, tolerate deer, some drought, and wind. They do best with regular water and they prefer sun. They grow fairly fast. Newcomers beware -- ‘fast’ by Alamosa growing standards may be much slower than what is considered fast in environments with longer growing seasons and milder weather than we have in the San Luis Valley.
Honeylocusts are doing well in Cole Park at the southeast end and along the 6th St. railroad parking lot. They like full sun and do OK in dry and alkaline soils. Once established they require medium to low rates of water. It is one of the last trees to leaf out (may be a benefit in cold years) and one of the first to drop its leaves in fall.
Elms are the largest of the trees planted along the 6th St. railroad parking lot and looked wonderful last season. The ‘New Horizon’ cultivar is still being evaluated in the National Elm Trial but seems to be highly resistant to common elm diseases. I don’t recommend it for very sandy soils.
Alamosa will see two Boxelder Sensation Maples (Acer negundo 'Sensation') this year – one in Carroll Park and one in Cole Park. It is really a maple and while it prefers medium water it is drought tolerant once established. It is tougher and has better branching angles (so not as brittle) than many other boxelders. Also, it doesn’t sucker. I look forward to seeing how these do in our city. They will have identification plaques installed this summer similar to those in Cole Park so we can all note their progress.
Smaller trees I would consider for shade in our valley include Tatarian Maple (Acer tataricum garann "Hot Wings"), Korean Sun Pear (Pyrus fauriei "Korean Sun"), and Canada Red Chokecherry (Prunus virginiana 'Shubert').
There are two maples along the north side of Main Street planted in 2009. One is in front of Mt. Blanca VFW and the other in front of St. Ives. They tolerate drought (once established) and alkaline soils. This is a patented variety developed in Colorado.
I love the pear tree at corner of Main and Edison. It has wonderful white flowers, small (if any) fruit, and red to re-purple fall color.
Due to the Emerald Ash Borer, I recommend you DO NOT plant an ash tree! See the column for March 5, 2014, at AlamosaTrees.net.
Think you want a large shade tree? I’ll address the issue in a later column.
Take a look at the Alamosa Tree Board recommendation list at AlamosaTrees.net for more information.
“It is well that you should celebrate your Arbor Day thoughtfully, for within your lifetime the nation's need of trees will become serious. We of an older generation can get along with what we have, though with growing hardship; but in your full manhood and womanhood you will want what nature once so bountifully supplied and man so thoughtlessly destroyed; and because of that want you will reproach us, not for what we have used, but for what we have wasted.” Theodore Roosevelt, 1907 Arbor Day Message