Try Using Less, or No, Chemicals on Your Roses
Roses are well leafed out by now and if yours are typical, every tender new bud is crowded with soft-bodied aphids, the true harbingers of spring.
Soon the unfortunate will find leaves dusted by mildew and in time the undersides will become coated with a bright orange disease appropriately called “rust.” When it becomes warm enough, nearly invisible thrips may stipple petals and microscopic mites will web the undersides of leaves. Downy mildew may lay siege, and a humid summer will bring on the dreaded black spot. And these are just the seven most-common rose problems.
Roses are subject to so many pests and diseases, it is a wonder so many of us grow them, though very few manage to grow them without defect. But there are a few gardeners who manage nearly defect-free plants without resorting to the common chemical controls, or fertilizers. Call them lucky, or conscientious, but they have forsworn Miracle-Gro and Malathion.
For over 10 years, Ivy Reid, a landscape designer, has been growing large and luscious roses in an island bed in her Pacific Palisades back yard, with “no problems, pests or diseases at all.” They are surrounded by a great many other flowers and the whole effect is of a wonderfully huge bouquet.
Hers is a completely organic, bio-dynamic garden, following the techniques developed by the founder of this organic movement, Rudolf Steiner. And if any plant should put these practices to the test, it must be roses.
Reid warns that this didn’t happen overnight, that patience and perseverance were needed. For several years after weaning the garden from Osmocote and other chemical fertilizers, she found some pests and diseases, but carefully picked off every leaf when it became diseased and every bug discovered. “Now the garden is full of butterflies and ladybugs and the flowers even smell better,” she said.
But expect a few problems while you better the soil and while pesticides wear off so natural controls can take over.
She begins her organic rose-growing year in January, when she carefully prunes all 30 plants and adds compost around the base of each. She uses a specially ordered bio-dynamic compost that is enriched with manure and other organic products, using about a single cubic-foot bag for every five plants.
She believes, as do most organic gardeners, that a healthy soil makes for healthy plants, “Healthy plants, like a healthy body, fend off problems,” she said.
She adds more compost to the soil surface in April, early summer (after the second bloom) and again in early fall. And that’s about it. “I’ve never found an easier, more effective way, of growing roses.” she said.
In Malibu, Andy Lopez says he knows of at least 6,000 gardeners that grow roses organically. He is a consultant, makes organic compost (enriched with llama manure and rock dusts), has organized a club for organic gardeners called the Invisible Gardeners, and recently published a book, “Organic Pest Control” (The Invisible Gardeners, Los Angeles: 19.95).
He knows there are 6,000 organic rose gardeners out there because he also started an organic gardening bulletin board for home computer users (The Organic Gardening Bulletin Board; call (310) 457-4268 to log on, or (800) 354-9296 for more information).
He looks at organic gardening as a lifestyle. “It’s no quick fix, “ he said, “but, like cooking, you get better at it” as you improve the soil and stay away from chemical fertilizers and sprays.
He feels that high-nitrogen fertilizers are the soil’s worst enemy and uses compost as his basic soil improver and fertilizer, as well as other organic fertilizers, such as alfalfa meal or compost tea (steep a cloth bag full of compost in water for five days). He is convinced that high-nitrogen fertilizers actually attract pests and thinks that “90% of the time, the real problem is nutrition,” the soil needs improving, with compost, naturally.
If pests do appear, his favorite remedy is a homemade soap spray, though his book suggests all sorts of non-chemical controls. He mixes a tablespoon of Dr. Bronner’s Peppermint Soap into a gallon of water and sometimes adds a couple of squirts of Louisiana Tabasco sauce, to make his own concoctions for spraying on all kinds of pests, from aphids to mites. He is especially wary of ants, which tend to bring other pests onto the rose bushes and he uses this spray at the first sign of them.
He prefers to spray late in the day, just as the sun sets, so the spray sits on the leaves as long as possible and doesn’t dry out. He also cautions that on especially hot days, the solution should be less concentrated (or simply wait for a cooler day).
“You do have to be diligent,” he said. “You can’t just ignore the garden until a pest or disease is out of control, and then try an remedy it.”
In his Altadena garden, Tom Carruth, horticulturist at Weeks Wholesale Roses, has discovered some help for pests and diseases, though he confesses to not taking the totally organic approach.
He has some interesting suggestions for rose diseases. By watering early in the morning, he manages to wash off powdery mildew before it has a chance to form. It grows in the dew of morning but can’t stand being totally wet.
By watering early in the day, he avoids black spot, which is caused by foliage being too wet, or the air too humid. He makes sure that rose bushes have plenty of air circulating around them so the leaves stay fresh and dry later in the day.
“Those of us from the East Coast learned not to wet the foliage on roses,” he said, “but that’s not the case in California. Wetting the foliage early in the day actually helps.”
He suggests a dormant spray for rust and downy mildew (a terrible misnomer for there is nothing “downy” about this disease that disfigures leaves and stems with dark purplish blotches). Dormant sprays, containing zinc or copper, are applied when the roses are leafless in winter and they head off diseases, cutting them by 90%.
For common pests, he has found that placing his sprinklers so to they spray up on the undersides of leaves, has dramatically reduced the microscopic web-forming spider mites. “They easily drown,” he explains. Aphids are as easily dispatched (just wash or rub them off) though he hasn’t found a way to battle summer’s thrips, which damage flower petals.
Carruth thinks that the secret to using less or no chemicals in the rose garden is to plan ahead, be persistent and “learn to deal with the fact that everything’s not going to be perfect,” which is probably as nature intended.
