Street Trees: Flaws vs Fatal Flaws

Street Trees: Flaws vs Fatal Flaws
Writer’s Question:
Our neighborhood, in south Bellevue, is losing many of its birch trees in the narrow three-foot wide parking strip
between our sidewalks and street. These trees were planted when the neighborhood was built in 1987, and were
probably a poor choice. I promised our home owners association I’d ask some questions regarding reasonable
ideas for replacement trees.
Cass’s Answer:
Almost all trees, like people, have their good and not so-good qualities. Sometimes they have a fatal flaw. If you
do find the perfect tree, it is probably overplanted. If you don’t mind looking at the same trees over and over, it’s
not a problem. I can tell you the perfect tree list is very, very short. To get a good tree, you might have to put up
with some particular flaws.
Everybody falls in love with a different tree, so they are often blind to the fatal flaws of their love. They go for
things like weeping cherry trees and Autumnalis cherries. Almost any ash is in danger of dying when the ash borer
gets here. My very best advice to you is, if two experts advise that you not plant a certain species, pay attention.
DO NOT PLANT is different than saying it has some flaws.
All trees grow way taller and wider than what is stated on the label. The label information is just the trees
average, mid-life size. You cannot stop trees from growing to their full size, or slow them down with pruning.
Believe me, I’ve tried.
Tall or big trees will bust up the sidewalk and road. On the other hand, the so-called small trees have their limbs
down where they interfere with vehicle and foot traffic. Lots of flaws. All trees drop stuff and not just leaves.
If it is a fast growing tree, it often busts up easily and dies young. Then we are sad. Many of the flowering trees
get serious, serious diseases.
Everyone likes long rows of the same species of tree because it looks so great when they do what they do, all at
the same time, like turn red in the fall, or bloom pink in the spring. But these trees are vulnerable to being wiped
out all at the same time…like the elms of the Midwest, or the ashes currently in mid Nebraska. The American
Chestnut, once common, is now extremely rare. If there is an absolute environmental precept, it would be that
diversity is good. Planting some of this and some of that can look very good too. Green Lake Park has a succession
plan. There are some trees doing something cool in all seasons. They are planted in rotation. With this system, all
the Xs turn red at the same time, all the Ys have pink flowers blooming at the same time, all the Zs have big red
berries in the winter, etc.
I like Laval’s Hawthorn (but it’s flowers stink, like I said, it’s always something). I’ve seen star magnolias that are
grafted on standards that would be good small trees. There might be a narrow Kousa dogwood. It seems to me
there should be some sort of Gingko that would work. If you’ve got wet enough soil and no overhead lines, maybe
a Katsura, but 3 feet is very, very narrow. You should be planting ornamental grasses, or asters, or scented hardy
geraniums, or something besides a tree.
I’m surprised that Bellevue will let you plant a tree in that small of a planting strip. I suspect the city will now have
an approved list. A lot depends on whether or not you have overhead wires.
For more information, any reputable nursery person, or any seasoned designer/arborist on the Plant Amnesty
referral service will have good ideas for you. I would especially recommend tree expert Jim Barborinas at Mt
Vernon’s Urban Forestry nursery. No doubt he has some other cool ideas for trees that will fit the bill.