Roses have a reputation for being fertilizer hogs, but that may not be valid. I have been growing roses for about eight years. Taking my cues from professional rosarians and the internet, I gave my roses everything that was recommended and then some. Of course, there is a fine line between overfeeding and underfeeding and there are many environmental and cultural variables that have to be factored into the equation. However, I have to say my roses have always thrived and bloomed from June through November so the advice was good. Or was it?
For six years I faithfully applied fertilizer (8-12-4) in mid April and then every six weeks until mid September. In addition to fertilizer I applied about one half cup of Epsom salt (for magnesium) to the soil around each plant. Then in mid November I put down a shovelful of manure, a handful of superphosphate, some lime, and a small volcano of mulch around the base of every plant. Two years ago I added a systemic pesticide product (there are several good ones on the market…I prefer Beyer) to the regimen and this was applied in the spring.
Well, last year I got lazy and only fertilized once, in mid April. Everything else remained the same. Much to my surprise, the plants seemed to be healthier than usual but I didn’t trust my observation so I decided to do the same thing this year. My friends began to comment about how robust and healthy the roses looked and then I knew it wasn’t my imagination last year. Except for the ever present and hideous black spot, all of the roses have stronger canes, larger, firmer, and greener leaves, and larger and more abundant blossoms.
I believe my new program has been successful because it may actually be stressful to overfeed roses…and probably other plants as well…especially when temperatures start climbing. Of course, the money I save by buying one container of fertilizer instead of five every spring is enough to buy several new rose plants every year. Now that’s what I call a win-win situation.