Thursday, April 24, 2014
By Tom Atwell firstname.lastname@example.org
It’s better to buy smaller trees, for your garden as well as your pocketbook. Slower-growing trees are usually stronger. Trees that bloom at unusual times get a lot of attention.
Those were three highlights of a talk on landscape design inspiration that Jeff Tarling, Portland’s city arborist, gave late last month at O’Donal’s Nursery in Gorham.
When Nancy and I plant trees and shrubs, for the most part we try to get them as small as possible, for a number of reasons.
Smaller plants of the same variety are less expensive, which never hurts. Just as important, larger plants are heavier and more difficult to move, and require a much bigger hole when you put them in the ground.
But most important, I have always suspected – and Tarling agrees – that they do better in the landscape.
“When I first came to work for the city of Portland,” Tarling said, “I would buy the 3-inch caliper (trunk diameter) tree. But I found out over time that a small tree grows a lot better. There is a lot less plant shock, and over time it will catch up.”
A lot of people, however, want instant gratification. Many gardeners are baby boomers or a bit older, and they wonder if they will ever get to see the small plant they put in the ground become a mature specimen. They’ll say something like, “I don’t even buy green bananas anymore.”
When you are putting in a new garden with small plants, the garden does look a little empty. But planting a tree is often something you do for future generations.
The same philosophy applies to the decision to plant a fast-growing tree or a slower-growing variety.
With maple trees, Tarling said, red maples – the native Acer rubrum – are generally stronger than the Freeman maples, which are hybrids of red maples and silver maples, a fast-growing but weaker tree.
White birch is another beautiful tree that has a lot of problems, and Tarling recommends river birch as an alternative. You can grow it either in clump form or with a single stem. The bark is a light cream color when it is young, but darkens as it gets older.
And there are varieties that can work in just about any landscape.
“ 'Little King’ is a dwarf variety of River Birch,” Tarling said. “It is a nice tree, and it won’t get out of control.”
Of all the trees that grow in the city of Portland, one that receives the most notice is the “Arnold’s Promise” witch hazel in Post Office Park, Tarling said. The tree flowers in March, when there is nothing else in bloom. A lot of people mistake it for a forsythia.
“This is a very good tree,” Tarling said. “It blooms for a month.”
There are a couple of other long-blooming trees that Tarling likes. Magnolia virginiana, or sweetbay magnolia, blooms later than most magnolias.
“This blooms in June and then continues intermittently through August,” he said.
He also likes dogwoods – both Cornus kousa, the Korean dogwood that is most often planted in Maine, and the Cornus florida, which is native to the United States but only marginally hardy in Maine, at least for now.
“The Kousa will bloom in late May, and the blossoms will last all the way to August,” Tarling said. “After the blossoms, you get the berries, which are just beautiful. And the Florida dogwood is even better.”
Tarling thinks the tupelo is an excellent native tree that has wonderfully bright red foliage in the fall. It is native to Maine, and is growing in popularity with a lot of different hybrids being introduced. It features glossy green leaves during the growing season that turn a bright red during the fall.
Tarling is also a big fan of the native shagbark hickory tree, which is not available from most nurseries. He thinks it is a stately tree that can grow to 100 feet tall and live for up to 200 years. (He does admit that it needs some room.)
Another striking native is the larch, or tamarack, a deciduous conifer, which is unusual.
Tarling said that when he was doing landscaping for the Casco Bay Bridge several years ago, he wanted a needled conifer at the Portland end of the bridge, but did not want to block the winter sun for a house at that end of the bridge.
When the first fall arrived and the tamarack needles began turning yellow before falling off, the homeowner called him up and said, “I love that tree, but I think it is dying.”
Tarling said that is one tree that you definitely have to explain to people before you include it in the landscape.
Tom Atwell has been writing the Maine Gardener column since 2004. He is a freelance writer gardening in Cape Elizabeth and can be contacted at 767-2297 or at: