The Dirt: Debunking gardening myths
When it comes to the spreading of misinformation, I sometimes think the Internet is even worse than Aunt Gertrude or neighbor Ed talking over the back fence. Inaccuracies, impossibilities, and terrible tips espoused as wisdom sprout willy-nilly from the web and, too often, readers fail to question any of it. Are these ideas science-based or just opinion? Is this advice even relevant to our region? At least Gertrude, Ed, and the like spoke from experience gleaned in their own yards.
Here are some myths and misunderstandings that irk, worry, and sometimes amuse me.
Ah-choo! It’s goldenrod!
If it’s August in the Northeast and you’re sneezing, goldenrod is probably blooming in the fields—but it’s not the cause of your allergy attack. In fact, it’s a safe bet that if it’s a pretty flower—petunia, coneflower, aster, or rose—it’s not allergenic. Colorful plants are showy to attract pollinators, whereas most ugly plants must rely on the wind. The greatest single cause of “hay fever,” or late summer/fall allergy symptoms, is exactly that: ugly, non-descript ragweed. One plant produces up to a billion pollen grains per season, and they travel for miles. The two kinds, short ragweed (Ambrosia artemisiifolia) and tall ragweed (A. trifida), are the cause of about seventy-five percent of hay fever suffering. Learn their identities and kill them before they produce seed. Then take a big bouquet of goldenrod home to admire, sneeze-free.
Moss means the soil is acid, so spread lime.
Bad idea. Spreading lime without knowing the soil pH is foolish because you risk raising the pH to a high alkaline level that won’t let plants grow at all. In most of the northern half of our region, including Buffalo, the soil is usually alkaline already and lime is the last thing it needs.
So why is there moss on Amherst and Lewiston lawns? Moss grows wherever the spores blow in and find available soil and turf grass that isn’t healthy enough to crowd it out. Some mosses thrive in sun or shade, moist or dry areas, low and even high pH. Grass mown very short also helps moss grow. Healthy grass trumps moss, so improve your lawn’s soil, reseed, give it light, and tend it well, and moss won’t be a problem. Under trees, use mulch or groundcovers. Or, let the moss grow, and enjoy its beautiful texture.
When a plant is stressed, fertilize it.
The most probable cause of plant stress is water—either too much or too little. Drought is exacerbated by wind, extreme heat, overly drained soil (sand), or soil that has no moisture-holding capacity (needs compost). Plants can also be stressed by physical damage, wrong soil pH, salt spray, winter injury, soil compaction, disease, insect assault, or recent planting (insufficient roots to keep up with top growth). Fertilizing is often the wrong thing to do, since it forces the plant to put its energy into growing shoots, leaves, and flowers just when it most needs to be growing roots. When in doubt, water plants deeply if they’re dry, improve drainage if they’re soggy, and fix the soil. Then get a good diagnosis.
Never water at noon or in the evening.
The best time to water is in the morning—or any time you can in order to avoid plant stress. When plants droop, they are stressed and becoming damaged. Noon watering does waste the most water (evaporation) and evening watering can leave a nice moist garden where slugs and fungus diseases thrive, but if noon or evening watering is your best time, then water you must. In evening, try to water just the soil beneath the plants and keep the leaves as dry as possible. (Then do nighttime slug patrol.)
To protect a new tree, mulch around the trunk and then stake it tight
Tell everyone you know to just stop “volcano mulching”—mounding mulch up around a tree trunk. Doing so causes rotting bark, which allows diseases or insects to enter. After a tree is planted, you should see an above-ground flare, where the trunk begins to curve outward into roots. Put mulch in a large circle (think doughnut) out from the trunk, but don’t let it touch the trunk or cover the flare. Then stake your tree only if it’s in a high wind area. Much damage is done by overly tight staking and/or failing to remove the stakes, both of which lead to girdled trees.
Ants help the peonies to open or Ants are eating my peony buds.
Neither is true. Ants like the sweet, sugary syrup often found on peony buds, but they’ll be gone soon after the flower opens and they do no harm.
Hostas and Astilbes are “shade plants.”
It’s time to distinguish between shade-requiring, and shade-tolerant plants. Many plants in garden center areas marked “Shade Plants” would really perform best if they saw a ray of sunshine once in awhile—or even a whole day of it! Gardeners need plants for the shade, these plants tolerate it, and so we group that way. Especially if they receive ample moisture, astilbes, many hostas, columbine, lobelias, and many more “shade plants” can even handle full sun. (Blue hostas lose their blue tones in bright sunshine, however.)
I see pine trees, so the soil is acidic.
Not necessarily. Many conifers, including some pines, can grow in a wide range of soil pH. And their needles, while acidic, would take decades or even centuries to affect the soil acidity if the bedrock or native soil is alkaline. It’s hard to fight native soil, whether you add pine needles, coffee grounds, peat, or even sulfur-based products, and over time it reverts to its original state. To grow a happy rhododendron, azalea, Pieris japonica, blueberries, or potatoes—which all require acidity—test the soil pH and lower it if necessary. Don’t trust the pine tree.
I’m getting only dwarf plants for my foundation beds; they won’t need so many haircuts.
Grrrr … “Haircuts” is a bad way to think about pruning anyway, since many beautiful landscape plants rarely need pruning and look better in their graceful, full-sized shapes. Ideally, choose plants with ultimate, mature sizes that don’t outgrow their spots in your landscape. But don’t trust the words like “dwarf,” “mini,” or “nano” because it’s all relative! A dwarf Alberta Spruce (“Conica”) grows to ten feet, which is quite tiny compared to the fifty-foot tall species. Common juniper grows to ten feet or more, and many a “low-growing” cultivar aims for five feet. Many a “dwarf” fir or apple tree will grow to twenty feet. You can’t keep plants healthy and good looking by regularly shortening them with “haircuts.” And not all dwarfs are short.
Wishing you all great sources in your fact-finding quests, as you pursue this great passion called horticulture.
Sally Cunningham is a CNLP (Certified Nursery & Landscape Professional), former Extension Educator and Master Gardener through Cornell Cooperative Extension, garden writer for many Rodale Books and Yankee publications, and columnist for the Buffalo News and Buffalo Spree. She is executive director of the National Garden Festival and consultant at Lockwood’s Greenhouses, and appears on WIVB-TV (channel 4) on Sunday mornings. Sally has gardened, worked, and educated others for twenty-two years in the gardening industry.