When I first started gardening at Landis, I was introduced to many tools, plants -- and ideas. Every gardener, it seems, had a different opinion on what to cut back and what to retain, when to plant and when to divide, even what to wear. It was gloves, sunblock, hats, and long sleeves for some; for others, shorts and tees.
One of the first “tips of the trade” I was introduced to was smothering weeds with paper products. In the Van Loveland Perennial Gardens, where a variety of shrubs, flowers, and bulbs are planted, weed fabric was not an option. Instead, newspaper became this gardener’s new best friend. The nearby My Shopper office was willing to donate reams of back issues. I would put down a thick layer of paper, then a layer of compost or mulch, and then water thoroughly. The site would remain weed free for at least a few weeks, and the newspaper would compost back to the earth before the next spring’s growth. The process felt clean and sustainable. We even used cardboard in larger open areas, such as around newly planted woody plant collections. In time, the weeds, especially the Aegopodium podagraria (bishop’s weed) and the grass, always came back. We also noticed a loss of many plants, such as California poppy, tall verbena, borage, even batchelor’s buttons, that should self-seed every year. We thought it must be wildlife snacking a bit too often . . . .
At this same time, I was working on my internship and undertook a small garden project around the old well pump in front of the Farmhouse, using a very different approach. I outlined a garden oval of about 12 feet and scalped the existing grass with a string trimmer as far down to the ground as possible. Instead of using paper or cardboard, I covered the new bed with about 12” inches of naturally mulched wood chips donated by the local electric company. I dug a few holes in the mulch and planted the bed. Even over several years, the “well pump garden” bed did not become infested with weeds, and the grass never came back. The phlox, columbine, and daylily continue to thrive.
Recently, I learned about the toxicity of using cardboard in the garden, especially where food crops are involved. The cardboard produced for shipping today is treated to be waterproof or water resistant and breaks down very slowly, leaching chemicals into the soil. These chemicals are not the type you would purposely put into your garden as they can kill and effectively sterilize the existing soil matrix. Studies have also proven that cardboard mulch doesn’t work as well as simply dumping at least 12” of clean natural undyed wood chips (sometimes called “arborist chips,” sometimes “playground chips”) onto the soil to deter weeds. These chips do break down over time, feeding the garden bed rather than destroying the existing ecosystem. Cardboard mulch can also provide habitat for pests such as termites and slugs. Cardboard may keep a wet site too wet, limiting beneficial air and water exchange. Sometimes water will run off cardboard rather than permeate through it.
Positive attributes of this type of gardening include higher production yields, reduced soil erosion, better aeration, and overall healthier soil. The process of smothering weeds with wood chips is less time consuming as well.
Gardeners learn through experience. As products and environments change, we must be willing to adapt. As gardens grow, we need to lean in closer to observe them. In doing so, we can gain greater wisdom, and both we and the plants we tend will be healthier for it.