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MONSOON SEASON OFFERS NEW ARRAY OF GARDENING CHALLENGES
The view from my window today is reminiscent of a rain forest. The relentless downpour signals that my rain gauge needs emptying - just under three inches of rain have fallen since midnight; 11-3/4 inches since June 28.
Less than a month ago I wrote in this space about 3/4-inch crevices in the soil and the urgent need for watering trees and shrubs. The turnabout feels like walking through a doorway that separates the desert from the jungle.
My attitude towards gardening - and I'm sure yours, too - has done an about-face in recent weeks. Sweltering heat and hoards of mosquitoes make weed pulling and flower picking much less enjoyable.
What problems does "monsoon season" present to gardeners? Plenty, according to horticulture experts at the University of Minnesota and phone calls I've been receiving.
Saturated soil puts trees at risk of tipping from any wind that exceeds breeze intensity. Dr. Peter Bedker, Dial U extension forester and plant pathologist, says Colorado Blue, Norway and white spruce are particularly susceptible to tipping because of their shallow root systems.
If your spruce or other trees are leaning due to recent wet and windy conditions, Bedker says you can pull them back to an upright position if their trunk diameter does not exceed four inches or - for larger trees - if they're not leaning more than 20ƒ from upright.
"When you pull a larger tree upright after it's blown over, it generally will not return to a healthy state because too many of its woody roots will have been severed," Bedker says. "Most trees simply cannot regenerate their larger woody roots and are prone to failure in the future." Bedker says it's generally better to remove these trees and start over with new ones.
What about staking trees as a preventive measure against future storms? Bedker says this is kind of like buying insurance - you may or may not realize the benefit later. "Personally, I am not staking the trees in my yard," he offered.
One reason trees tip, according to Bedker, is that they were doomed to tipping from the day they were planted because of the way they were grown in the nursery. Homeowners often unintentionally plant trees too deep, in other words.
It's a common nursery practice, according to Bedker, to purposely push soil around the base of trees during cultivation to discourage weed growth. Later, when trees are mechanizally potted or balled and burlapped, this added soil is not removed. As a result, several inches of soil have been added above the root collar (the point where branch roots begin flaring sideways). Homeowners who plant these trees often simply drop the root ball into the ground and shovel a little more soil on top for good measure. Then, if the three settles, it ends up in your yard stuck in soil 6 - 8 inches above the root collar.
These deep-planted trees are far more susceptible to being snapped off at ground level from heavy wind because the roots never got started correctly in the first place. Girdling roots may form just below the surface, literally strangling the stem and causing collar rot.
Best advice when planting new trees is to unwrap the burlap and dig away soil at the top of the ball until you uncover the root collar. Never plant trees deeper than the distance from the root collar flare to the bottom of the soil ball. The root collar flare should be at or slightly above grade.
One other rain-caused problem in trees and shrubs is fire blight. Mountain ash, apple, crab apple, cotoneaster and raspberry are most susceptible to fire blight, which is characterized by sudden wilting and dying of branches or the entire tree. Dial U reports they've received many fire blight calls in recent weeks.
Fire blight is caused by a bacteria that can actually be forced into leaves by heavy rains. If you notice sudden wilting on branches of any of the trees and shrubs listed above, you should remove the infected tissue immediately by cutting out the branches at least 10 inches beyond the wilted tissue, destroying the infected tissue, and disinfecting your shears in a 10% bleach solution between every cut.
Does six weeks of drought followed by a month-long monsoon kind of make you wonder what's coming next? I'm not predicting snow in August, but some odds makers may just be willing to take that bet!
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PUTTING DOWN ROOTS:
A Delightful Blend of
Gardening Wisdom, Wit
and Whimsy
$10 + $2 for shipping
by Cliff Johnson |
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