Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
6/28/99
Contacts:
Jeff Iles, Department of Horticulture, (515) 294-0029,
iles@iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Yard and Garden Column for the Week Beginning July 2
An Early-summer Landscape Check-up with the Plant Guy
By Jeff Iles
Extension horticulturist
Iowa State University Extension
Hey, Plant Guy:
To say that I'm embarrassed would be the understatement of
the year. You see, my large, magnificent elm tree seems to
be leaking! That's right. Dark, foul-smelling liquid is
oozing out of my tree at a point where two major branches
come together. And to make matters worse, as this vile fluid
makes its way down the trunk, it turns the bark white, and
then kills the grass at the base of the tree. Why would a
tree do such a thing? Of course, my dogs love the stuff, but
then dogs seem to have a special fondness for all things
putrid. Yesterday, a neighbor suggested I hammer a steel
pipe into the tree and drain the obnoxious discharge into a
bucket. Sounds like a good idea, except I'm not sure where
I'll be able to dispose of the evil brew. Furthermore, once
tapped, I'm wondering if my tree will start producing like
"Old Bossy" down on the dairy farm. I'm looking to you for
answers Plant Guy. The neighborhood homeowners association
is threatening to take action.
Oozing in Oelwein
Dear Oozing:
Let's see. How do I put this tactfully? Your tree seems to
have a case of the vapors. Oh, alright, your tree has gas!
Actually, the affliction is called wetwood or slime flux
caused by the activities of several bacteria that live in
the wood and ferment the sap of trees. Bacterial wetwood can
be found on a wide variety of trees but is most common on
elm, mulberry and cottonwood. The most conspicuous symptom
of the disease is the oozing of sap or "bleeding" from trunk
wounds, cracks and other openings. Sap is forced out of the
tree due to a build-up of gas (primarily methane, nitrogen
and carbon dioxide) produced by the fermenting action of the
bacteria. Pressures of 5 to 10 psi are common; however, high
pressures up to 60 psi are possible. Now oozing sap is
pretty harmless stuff. Harmless, that is, until air-borne
bacteria, yeasts and other fungi contaminate it, turning it
into a frothy, slimy, reeking concoction. But as socially
unacceptable as this effluent is, it is not a serious
problem for the tree. In fact, installing a drain pipe as
your neighbor suggests may cause far more damage to the tree
than the disease itself. So let's ease up on this poor elm.
Even trees must vent now and again.
Hey, Plant Guy:
They say "confession is good for the soul" so here goes.
Earlier this spring, I had a little accident with some weed
killer. All right, it was a pretty big accident. I was
treating my yard for dandelions, and it seems some of my
herbicide found its way into my neighbor's garden. I had no
idea a 20 m.p.h. wind would carry that stuff into his yard.
Anyway, I (the herbicide) killed most of his vegetable
plants and did some crazy things to a tree he calls a
redbud. Suffice it to say, my neighbor wasn't too happy, but
he seemed to calm down a bit after I wrote him a check for
the damage. We'd even started to speak to each other again
last week, so I figured the whole mess had kind of blown
over, if you catch my drift. But, when I got home from work
today I discovered my neighbor had planted a row of
something called 'Techny' arborvitae directly on the
property line that separates our yards. He says it will keep
all of those yard chemicals I use from wafting onto his
property. Fair enough, but just how big does this 'Techny'
plant get? Right now they're about 2 feet in width, but if
they get any wider they'll be in my yard! I sense another
confrontation is just around the corner Plant Guy. Tell me
these plants will only grow taller.
Losing Ground in Grimes
Dear Losing Ground:
O.K. Those plants will only grow taller, the hair on the top
of your head is getting thicker and gasoline will sell for
$.25/gallon this weekend. Of course 'Techny' arborvitae will
get wider! A lot wider. In fact, you're looking at a mature
spread of about 10 feet or so. The good news is, only
one-half, or about 5 feet of your neighbors hedge row will
be on your side of the property line. What can you do? Well,
you could simply accept your neighbor's plan for protecting
his veggies and convince yourself that by forfeiting some of
your side yard you'll be the one responsible for keeping
peace in the neighborhood. Besides, your magnanimous gesture
means less mowing and fewer dandelions to contend with. Or,
you could suggest your neighbor move his plants further into
his yard, away from the property line to avoid any potential
boundary disputes. After all, there's a chance he wasn't
aware of how large 'Techny' arborvitae can get. You might
even offer to help with the transplanting. Nothing like
sharing a little hard work on a warm summer evening to mend
a fragile relationship.
Hey, Plant Guy:
As I was passing through a residential section of town last
weekend I spied a beautiful yellow-leaved tree growing in
front of a brown, ranch-style home. The color contrast was
breathtaking. As luck would have it, the man of the house
was outside mowing the lawn, so I stopped and asked him what
kind of tree it was and where I could purchase one just like
it. Well Plant Guy, I thought he was going to pop a vein.
I've never seen anyone get mad so quickly over a simple
question. Thankfully the guy's wife stepped between us, and
as she was ushering me back to my car told me the name of
the tree was pin oak and that it wasn't supposed to be
yellow at all. I'm sure there's more to this story but I
didn't dare ask any more questions. The point is, I like the
look of yellow-leaved plants in the summer landscape. Can
you suggest a few trees and shrubs that are yellow and
healthy at the same time.
Tired of Green in Greene
Dear Tired of Green:
Nice going. The poor guy is out mowing his lawn, minding his
own business, and you waltz in and remind him of his
inability to grow a healthy tree. Actually, a lot of people
have trouble growing pin oak on soils with a high pH, but
that's a discussion for another time. As for your question,
one of my favorite yellow-leaved trees is Princeton Gold
Norway maple. In a sea of green this tree is a knock-out! If
you like evergreens try Sunkist arborvitae. Its
orange-yellow winter foliage turns bright lemon-yellow in
spring and summer. And if deciduous shrubs are what you're
looking for, try Golden Carousel barberry, golden
mockorange, Dart's Gold or Nugget ninebark, golden elder,
and Goldmound, Golden Princess, or Mellow Yellow spirea. Now
a word of caution: Be careful with how much yellow you
introduce into your landscape. If people start mistaking
your mailbox for a drive-up window at a fast-food
restaurant, you know you've gone too far.
ml: isugarden
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