To Fertilize or Not to Fertilize: That is the Question
Because it has slowly dawned on me that my roses would have benefitted from more nourishment during this past growing season, I have begun to ponder the complexities of fertilizer. I tend to under-fertilize, partially because I have good soil and partially because, well, lethargy settles in during our hot, humid summers. But I am a determined gardener. So with great energy and good intentions, I plunged into the world of rose fertilizers — an exploration not for the faint of heart, as I slogged through blood and bone meal, sludge, and fish emulsion.
Let me say this at the start: Every rosarian has a different formula, so there is no straight path to fertilizer truth when it comes to roses. For example, Pam Powers, president of the Arlington Rose Foundation, relies on spring and fall applications of a combination that includes Milorganite — sometimes inelegantly referred to as sludge, blood meal, fish meal, and alfalfa. Every two weeks her roses receive an application of fish emulsion and “humantes,” which apparently is a concoction that allows roses to become efficient feeders. Googling “humantes” led me to Erasmus. A philosopher of fertilization? I had to reach for the wine bottle to continue on.
In contrast, Pat Henry of Roses Unlimited dissolves a monthly feeding of one tablespoon of Mills Easy Feed, one tablespoon of chelated iron, and one tablespoon of Epsom salts in a gallon of water. Similarly, the New England rosarian Teresa Moshe is a firm believer in Epsom salts. After pruning her roses in the spring, she spreads one cup of Epsom salts around each bush.
Epsom salts? The stuff you use to soak your feet? Now the gardening world is divided on the value of Epsom salts. While it looks like salt, it isn’t salt. Even its name holds no agreement: Some insist it should be “Epsom salts,” while others use the term “Epsom salt.” The story behind it is this: In 1618, a farmer living in Epsom, England, noticed that cows would not drink from one of the wells on his property. He also discovered that washing his arm scratches in this same well water caused the skin to heal quicker. When boiled down, this water became hydrated magnesium sulfate, which he promptly named Epsom salts.
Rosarians quickly embraced it, as magnesium and sulfur are essential for good plant growth. Today the American Rose Society advocates spreading one-half cup of Epsom salts — along with one cup bone meal, one cup cottonseed meal, one-half cup blood meal and one-half cup fish meal — around each rose at the drip line and watering in well.
Outside of the rose world, Epsom salts is met with a degree of skepticism. Sandy soils can have a magnesium deficiency while clay soils typically exhibit such a dearth only if the soil has been overworked. An excess of magnesium, frequently present when there is a potassium excess, becomes a soil pollutant. Contrary to rumor, spraying Epsom salts on roses does not discourage pests. And almost all experts will tell gardeners to get a soil test before applying Epsom salts. Can the American Rose Society and innumerable rosarians be wrong about the virtues of Epsom salts? Is there no final authority to settle this debate?
The Epsom Salt Council — yes, there really is such an organization — instructs us to soak unplanted roses in one-half cut of Epsom salts dissolved in one gallon of water. Once planted, each rose should receive one-half cup around the base (watered in well) with a biweekly diet of one tablespoon of Epsom salts dissolved in one gallon of water. I have at least 45 roses scattered throughout the garden. I heard the question: What did you do last summer? My response: I did nothing but feed my roses.
By now my head was spinning. The experts all agree on only this: A gardener should spread a fertilizing mixture around the drip line before watering it in well into the soil. The problem lies with the concoction — no one agrees what it should contain. Another formula put out by the American Rose Society calls for one-half cup Milorganite, one cup alfalfa meal, and something called Sul-Po-Mag spread around each rose in the spring and summer with one-half teaspoon of chelated iron, one cup Epsom salts, and one teaspoon of fish emulsion dissolved in one gallon of water given at monthly intervals. Sul-Po-Mag is only used in soils with a pH over 7, so I could quickly scratch that off my list, as our soil in the Piedmont is on the acidic side.
I had not realized that fertilizing roses took so much work. But I couldn’t just throw my hands up in despair — and neither can you, good reader.
I turned to Martha. Surely, if anyone has the answer, it would be Martha Stewart. Approving of Epsom salts, Martha gives her roses three-quarters cup every spring, mixing it into the soil at the drip line with a cultivator. The National Gardening Association has tested Epsom salts on roses and finds that those roses treated with Epsom salts have greener foliage and stronger canes on substantially bushier plants. After the toxic summer we just experienced, my roses had shed so many leaves that, of course, I wanted bushier roses — everyone seeks to have fuller rose bushes.
I still had bone meal, blood meal, fish meal, fish emulsion, and alfalfa to consider, but I — like you — was tiring of the subject. Surely, there had to be a magic potion somewhere. I noticed general agreement that alfalfa meal is a good thing. A member of the pea family, alfalfa is high in nitrogen, calcium, and magnesium, so a cupful watered in around the drip line is beneficial, many rosarians believe.
Visions of 50-pound bags of all these nutrients began to haunt me. Where would I put them? Should I, at my delicate age, be hauling around 50-pound bags of anything? Exhausted, I couldn’t push myself into the merits of fish emulsion, kelp, soybean meal, and blood meal.
So what did I decide to do? Because rosarians swear by Epsom salts — as does a dear friend who’s also a rosarian — I’m adding it to the March rose diet. I already use Mills Easy Feed on a monthly basis but shall start April off by spreading two cups of Mills Magic Mix around the drip line of each rose bush. As the Mills Magic Mix includes “alfalfa meal, fish meal, bone meal, cottonseed meal, blood meal, activated sludge, and an organic activator,” it seems to me that I will have killed lots of birds with one stone. A 40-pound bag will feed 50 roses.
And then, as God is my witness — to paraphrase Scarlett — if my roses don’t thrive, stunning everyone with their beauty, I shall personally decapitate each and every one of them.
Originally published at www.seniorcorrespondent.com on October 27, 2016.