Eco-gardening is at its best in The Monday Garden
October 23, 2005, Issue 183
Gardeners hear time and again “never put down more than 3 inches of mulch - you'll smother the plants and neighboring tree roots”. Well, sometimes that's a good thing. Sometimes, you want to clear an area of whatever is there and don't have any surrounding treasures to guard. You could do this by sterilizing the soil over several months with a black trap cover but that very extreme and not always needed or the right way to go. Sometimes, the best thing is to just pile on the mulch, the more the merrier.
Two uses of mulch to smother come to mind: making new gardens from lawn and controlling invasives.
MAKING GARDEN FROM LAWN, THE EASY WAY
To make garden from lawn: The Monday Garden Great American Gardener way to make garden from lawn is very simple.
STEP ONE: Outline the area you want to convert to garden with bricks, rocks, a shallow trench, a hose, or whatever. Cover the area with several inches of mulch. Add a few stepping stones so you can reach all parts of the garden without stepping on the soil. Next, go watch the World Series, make a quilt, or cook Thanksgiving dinner. Meanwhile, the sod quickly starts to rot, while the earthworms and other critters begin mixing the mulch (including the rotted sod) down into the soil.
Picture: STEP ONE: start the new garden by laying down a thick coat of mulch. This planting is being done at the last minute in June. Note all the lovely clover in the lawn. Stamford CT 2005
STEP TWO: Come back a week later with your starter plants, dig a hole through the mulch, etc., 2 or 3 times the diameter of the plant. Insert plant; re-fill the hole with the loosened dirt. Recover the soil around the plant with mulch but keep the mulch a couple of inches away from the plant's crown and don't put more than 2 inches over the plant's roots. If you've picked hardy garden-survivor plants, there's no need to do anything more except water as needed.
STEP THREE: In the fall, under-plant the new garden with spring bulbs; next spring you'll be delighted that you did.
Experienced, classically-trained gardeners may be shocked that the soil of the new garden bed wasn't tested, double dug, sifted, and amended with every known plant nutrient. If you're trying to raise plants the size of Hummers, I guess you could invest all that time, labor, and money, introduce foreign things into the earth, open up the soil's bank of weed seeds, and seriously annoy and/or kill off your micro-soil critters. The gardener, who just wants easy-care plants that are happy in the naturally existing conditions to provide beauty for the humans, and pollen, seeds, and fruits for the wild critters, can skip all that, because this easy method works just as well. Instead, use the time to play with the grandkids or march for world peace.
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Pictures: STEP TWO: About a week later, acquire some plants. Here, the seller is one of the good guys -- Stamford's Lenny Scinto, who has done so much to spread the word on organic gardening. The new plants for this full-sun, low-water garden extension are a hybrid melon-colored cone flower, a bright pink “Almost Wild” single rose, and a lavender Russian sage. Also to be added by dividing plants in the existing garden are stella d'oro day lilies, field daisies, shasta daisies, blue common violets, and a common milkweed. In the fall, daffodils and narcissi will be transplanted from over-crowded beds in other parts of the garden.
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Pictures: the new garden immediately after planting in June and again in late September. After the picture was taken, the rose did consent to bloom some more in October.
CONTROLLING INVASIVES, THE EASY WAY
To control invasives with mulch: First, check to make sure that you won't smother the roots of a near-by tree or other wanted plant. Second, cut the invasives back as much as possible, leaving the cuttings in place. Third, put down 1 to 3 feet of mulch. Cut off anything that manages to poke up through the pile. If the area is not going to be cultivated in some way, repeat every couple of years to prevent re-infestation by the bad guys.
Piling up the mulch is a good low-labor technique for controlling invasives along the edge-of-forest, etc. Just be carefully to leave a few feet of open ground around the good guys such as native sassafras and blackberries that also enjoy this environmental niche.
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Pictures (above and below): the alley edge is choked with mugwort and porcelain vine; several truck loads of mulch are delivered and spread with a pitch fork. Hoyt Street Alley, Stamford CT Summer 2005
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This is the technique used along Hoyt Street Alley, the alleyway behind my high-rise, to control the invasives along the edge of the parking area. The landowner uses wood chips from a local landscaper. It's probably a win-win swap where the landscaper gets a free place to dump excess chips and the landowner gets the value of the free mulch.
You would think that this thick layer of mulch would kill the abutting trees. However, it doesn't seem to affect those trees whose trucks are not touched by the mulch because they have plenty of open ground on their other three sides for their roots. Those trees that are directly the mulch's path, particularly the young ones, that get the bottom of their trunks buried and who get surrounded by mulch, tend to die.
In Hoyt Street Alley, the mulch rots and compacts down to street level every couple of years, and the weeds (both good and bad) fill in again. So a new load of mulch is added and the process starts over again. Long term, I suspect that the alley trees large enough, or far enough back from the street, to withstand the mulch applications actually benefit from the mulching. The trees include red oak, sycamore, shag-bark hickory, elm, ash, hawthorn, catalpa, chokecherry, crab apple, eastern cottonwood, mulberry, box elder, ailanthus, and Norway maple.
Picture: the alley edge is looks much neater; the mugwort and other undesirables are controlled; and the trees don't seem to suffer.
Photo credits: Sue Sweeney
© Sue Sweeney 2005