Q: The leaves of our Greenspire Linden are curling. Do you think they’ll recover? — MM.
A: The curling, cupping and abnormal growth of leaves shown in the photo are classic symptoms compatible with herbicide exposure.
Trees can be exposed to herbicides in several ways, including spray drift or volatization through the air, but also through the root system, as some active ingredients readily move down through the soil and are easily absorbed by roots and taken internally into the tree’s system.
Will the tree recover? Much depends on the herbicide product that caused the damage and its active ingredients. Some herbicides are more damaging long term than others. There’s not much that can be done, other than wait-and-see. There’s no effective way to reverse the condition once the herbicide has been absorbed into the tree.
The hope is that the linden will overcome the current damage and grow normally in the years to come. Whether next year’s growth emerges normally will tell much.
Exposure to herbicides can make trees more susceptible to winter damage, disease, insects and other secondary issues that prey on weakened trees.
Q: My lawn has started to give off an orange powder that is covering my shoes when I walk across it, and the lawnmower is also getting covered with orange dust? What’s causing it, and how can I make it stop? — Ted M.
A: The orange powder is the result of lawn rust, a disorder caused by a type of fungus. Although it’s annoying, the good news is that it doesn’t really affect the lawn’s health.
Lawn rust is an indicator, though, that the grass is likely running out of nutrition. Lawns with sufficient nitrogen, the main ingredient in lawn-type fertilizer, are less likely to develop rust.
By mid-to-late summer, many of our lawns have exhausted the supply of fertilizer we applied around Memorial Day, becoming more susceptible to rust. Unless a lawn is green, actively growing and well-watered, fertilizing in the heat of summer isn’t recommended.
Applying fertilizer around Labor Day will recharge the lawn’s nitrogen supply and provide nutrition for a thick, healthy turf.
Q: A number of our Honeycrisp apples recently blew off our tree in heavy winds. Most are still green, but healthy looking, about the size of a tennis ball. Is there any way to ripen them once they are off the tree? — Gordon M.
A: Although allowing apples to ripen fully on the tree is desired for peak flavor, sweetness and quality, sometimes that’s not possible. In fact, the University of Minnesota says, “to make sure apples survive long-term storage, orchards harvest them one-to-two weeks before peak ripeness.
“Apples are a ‘climacteric’ fruit, meaning they continue to ripen somewhat after picking. If you have to pick early, try storing the fruit for a while to see if they become sweeter before use.”
Key words in the statement seem to be “ripen somewhat.”
Since you’ve nothing to lose, you might try placing some in a brown paper bag, which traps ethylene, the “ripening gas,” to see if that helps.
Much will depend on whether the fruits have progressed to a stage where a little further ripening is possible. Even if they don’t ripen further, the apples can still be used in sauce or pie, likely with a little extra sugar needed.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at
donald.kinzler@ndsu.edu
. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.