Q. Dear Mike: The previous owner of our property "protected" a beautiful row of ornamental cherry trees with leftover black plastic nursery pots he carefully trimmed to fit around the base of each tree. I'm enclosing a photo of the result—with the mousy bedding still in place. I hope this can help you educate your listeners about the similar folly of mounding huge piles of mulch into "volcanoes" around tree trunks. Best Wishes.
- ---Dick (aka "Brambles"--it's a long story, and you're to blame!) West Bradford Township; Chester County, PA
There are many reasons not to surround the base of your trees with volcano-like mounds of mulch (one arborist I know calls them "Tributes to Pele"). More than an inch or two of any kind of mulch prevents water from reaching plant roots and starves the ground itself of essential oxygen. If the mulch itself is wood chips, shredded bark, 'root mulch' or other wood, it can also steal plant-feeding nitrogen from the soil, sometimes starving the poor tree to death.
But the biggest reason is now getting really, really hungry: Mice, voles and other noxious nibblers that hope you heap on the mulch so they can chew away at that tasty outer bark unseen. Thanks to the cover you provide, free-roaming cats can't stop them; hawks, owls and foxes can't prey upon them. And once they've eaten a complete circle around the bark, the tree is doomed; that outer layer is the only part that can convey water and nutrition to the top. Once it's girdled, your treasured tree becomes expensive firewood.
We don't mulch plants to keep them warm; no mulch can do that, and plants don't need it. We mulch plants to keep the surface of the soil at a more constant temperature over winter. This prevents the heaving and thawing that can occur when we roller coaster back and forth between freezing cold and unseasonable warm spells—sometimes moving soil around so fiercely it pops unmulched perennials, Spring bulbs, garlic and the like right out of the ground!
Note that I didn't include trees in that list. Established trees need no mulch. God don't mulch 'em, and neither should you. In colder climes, newly-planted trees could benefit from an inch or two of shredded leaves; but wait until after the ground freezes hard to apply it—or any winter mulch. And never let any mulch touch the actual plant stem or trunk—ever, ever, ever! Remember—you're mulching the soil around the roots to prevent heaving; not giving your hemlock a hot water bottle.
The warmer your clime, the less you need to mulch anything over winter. (Save that mulch to prevent weeds next summer!) But listeners North and South might want to do something else to really protect newly planted trees. When vermin get hungry enough, they'll try and eat that tasty bark despite the risk of their becoming dinner for a kitty cat or raptor. And if you live in one of our colder climes, be aware that a couple inches of snow provides the same protective cover as a bad mulch job.
So either use professional tree protectors or get a roll of hardware cloth (it's made of metal; kind of a cross between very small gauge animal fencing and the strongest window screening in the world) and wrap it around the bottom couple feet of newly planted trees—maybe even a few priceless older ones if you get lots of snow and/or have seen nibble marks in the past. How high you should protect depends on how much snow you typically get. Remember—mice and voles will attack from below, but hungry rabbits will walk on top of that snow.
This is also the time of year "house mice" earn their name. The chilly temperatures send them inside—they can squeeze through impossibly small openings—to eat your stored food and leave you those wonderful little pellets in return. Don't wait till you hear noises in the walls. Keep all your cabinet and pantry food in mouse-proof containers, and be ready to set a few traps at the first sign of nibbles and small gifts.
Basic old-fashioned snap traps work well. Wear gloves while you handle the traps to disguise your scent, bait them with peanut butter (the universal malicious mammal attractant), and place them right along the walls in rooms you've seen evidence of mouse action. Check them regularly; and if you make a catch, keep the traps in place for a while. There's rarely a single mouse a foot.
No matter what, do not use poisons! Yes, I always say that—and I'm always right! In this case, double. A poisoned mouse could be eaten by a cat, hawk, owl or other helpful member of the vermin control team; wait till you see how many mice show up to take advantage of that absence! And more personally: Do you really want to experience what its like living in a house where poisoned mice have crawled deep into the walls to die? And you thought your football team stank!
Some ingenious devices get around the 'ick' factor of snap traps by capturing mice alive. I tried a grey plastic one, but didn't like it because you couldn't tell just by looking whether it had caught anything or not; and I got tired of picking it up and shaking it around. "The Mice Cube" is much better; its made of clear plastic, so you can tell at a glance if it has a mouse inside or not. (Gardens Alive used to sell it, but stopped; you can probably find them elsewhere on line, I betcha.) I still have mine and will be leaving a few around this fall in areas I've had mouse problems in the past to 'see' what I catch. (Get it? "See" ?) Yeah, I know—har de har har.
Anyway, back when they sold it, my foolish friends at GA used to point out that since the mouse is trapped alive and unharmed, you can release the poor cuddly little creature outside without harming it. Sounds like somebody saw too many Disney movies to me. Let's just say that what you do with that cute little captured bag of Hatha virus is up to you, and leave it at that.
Hey—do I hear water running in the sink?