Another tree that impresses O'Brien is the medi-
um-maturing, fruitless and thornless 'White Shield'
osage orange (Maclura pomifera). "It's been
extremely drought tolerant and has a nice upright
spreading habit, and the foliage is dark green and
shiny, with a golden yellow fall color," he says.
A small-maturing winner for Columbia is the
American plum aka wild plum (Prunus ameri-
cana), which is native to Missouri and can be
grown multi-stem or single-leader. The ¾"-1" fruit
is edible and can be utilized for jellies or jam. "I
don't think of that as the key feature of wild plum,
however," O'Brien says. "I cherish wild plum for
its adaptability in naturalized urban landscapes
and ecological restoration projects. Tough as nails,
it'll thrive in some of the worst conditions, and
it won't need a lot of coddling to become estab-
lished. We planted a number of wild plums in the
Columbia 3M wetland project for example, and
the trees did really well. More importantly, this
tree fills an important ecological niche, as habitat
and food source for all manner of wildlife."
At a recent MCFC Conference, O'Brien—always
interested in edible plants—learned about the
use of jujube trees, also known as Chinese date
(Ziziphus jujube), in urban food farms. "That
was a revelation because it's small, beau-
tiful, easy to grow, produces tasty fruit, and
the public is much more likely to have success
with it in our humid climate than they would
with persnickety fruit trees such as sweet
cherry or peach trees," O'Brien says. >>
Drought tolerant and tough, this fruitless osage orange (Maclura pomifera 'White Shield') is a fantastic street tree
for difficult sites. The left photo shows a young tree protected with a cage, something Columbia uses for trees in
high-vandalism areas, such as near popular raucous bars or nightclubs. The right photo shows the habit of an
established young tree. Left photo by Brett O'Brien, right photo courtesy Cornell Woody Plants Database
28 CityTREES
