Lexington, KY - There are landscape practices that make me wince, that pain me to the core. What better time to hope for change than the beginning of a new year? Here are the top three on my landscape hit list, in no particular order.
Improper mulching of trees
Mulch is a layer of materials applied over the root zone of trees that is designed to imitate a natural forest environment. Trees in the woods are growing in rich, well-aerated soil full of essential nutrients. This soil is covered in leaves and organic materials that replenish nutrients and provide an optimal environment for root growth and mineral uptake. (No one rakes leaves in the forest. Our tidiness interrupts a natural cycle in which the tree produces its own nutrients.)
Mulch rings around trees are important for the health of the tree -- a big improvement over grass. Your lawn needs cutting and lawn mowers can wound surface tree roots. Weed whackers make slashes in the bark. Also, grass competes with trees for the same nutrients. This competition can make it difficult for a young tree to establish its root system and can stress even a mature tree. Mulching reduces water loss from the soil, minimizes weeds and improves soil structure.
The right amount of mulch, in the right place, is a good thing. Too much mulch or mulch piled against the trunk of a tree is a very bad thing.
Mulch should be two to four inches deep -- no more. It is critical to keep mulch away from the trunk of the tree to avoid overly moist conditions which promote trunk decay and can lead to insect and disease problems. Many of us like to refresh our mulch each year, which can result in heavy mats of mulch over time. You can rake up the existing mulch to break it up and refresh its appearance rather than adding more, or remove the old mulch before applying new material, if the mulch layer is too thick.
A mulched area that extends to the drip line is ideal, but smaller is better than not at all.
The existing practice of more is better, with mulch piled high around the trunk in "mulch volcanoes" is bad for the trees, and unattractive to boot.
Heavy use of herbicides, pesticides and fertilizers
You've seen those little flags warning about a recent herbicide application: "Stay off the grass" --
best to pay attention.
The Ontario College of Family Physicians has concluded that children are at serious risk from lawn and garden chemicals. Because they play outdoors, they are more likely to come into contact with such substances. Research suggests that exposure to these chemicals during prenatal and early childhood development can result in permanent loss of brain function.
Adults aren't safe, either. Some chemicals used on urban lawns have the potential to disrupt our hormone and endocrine systems, which can lead to decreased immune system function, impaired reproductive abilities, behavioral changes such as attention deficit and hyperactivity disorder, and increased susceptibility to breast and testicular cancer.
And then there is the overuse of fertilizers. Chemical fertilizers reduce the population of good soil microorganisms while increasing the number of harmful organisms. In an overly fertilized garden heavy with chemicals, there aren't enough beneficial soil organisms to hold on to the nutrients. On average, homeowners use 10 times more chemical pesticides and fertilizers per acre than farmers use on farmland.
Invasive exotic plants
I recently removed a huge burning bush from my backyard that gave me great screening and privacy. No matter, it had to go. Why? Because when I went for a hike last fall in the very beautiful Lower Howard's Creek area, what did I see? Those telltale red leaves were spotted throughout the woods. I plan to replace it with the native blackhaw viburnum (Viburnum prunifolium), a large shrub with beautiful spring blooms, followed by showy, edible berries and good fall color -- beats that nasty burning bush hands down.
Once you know what to look for, you'll see evidence of invasive exotic plants most everywhere. Miscanthus, an ornamental grass, has heavily infested the sunny areas at the Red River Gorge. And look around Lexington in the spring for the telltale white blooms of pear trees that have escaped cultivation. They're all over the place. Then there are the various species of invasive honeysuckle.
You can get information about the plants that have become threats in Kentucky at www.se-eppc.org/ky/list.htm.
These plants are displacing native plants and altering wildlife habitats. Garden centers still sell them and people still plant them. What to do? Dig them out. Stop selling them. Stop planting them.
No more mulch volcanoes means using less mulch. Reducing or eliminating the use of herbicides, pesticides and fertilizers will also save you time and money. And adding native plants that thrive in our local conditions, while removing invasives that just don't belong here, means healthier gardens and more birds and butterflies.
What can we do about over mulching, the use of invasive plants and overuse of chemicals of all kinds? This really is a simple matter: just stop it.