The Saturday Question: Organic Pesticides and Herbicides–What Have You Tried?

I’m all about organic gardening. In fact, even since I became a homeowner in 2004, I’ve managed to use completely nontoxic methods. Now that I’m in my new place, however, I have a problem: aphids. My new yard features about fifty-five rose bushes, and a couple of them happen to be bug-magnets. I tried an organic spray, which does get rid of the aphids–but also turns the leaves strange colors. I’ve bought bags of ladybugs, but they didn’t seem to stick around long enough to do much good. For now I’m just keeping my eye on the aphids and cutting off the leaves and blossoms they congregate on. Any other solutions?

Just one of my fifty-five rose bushes.


  1. Try diluting the organic spray with;

    1 part spray
    1 part water
    1 part vinegar


    Florida Herb House

  2. I’m not sure if it’s organic but there is this spray that is basically just soapy water and it works great. I’m sure you could make it with organic dish soap. Okay, I looked and guess what it’s called, insecticidal soap! I have never seen it turn the leaves strange colors but is it possible your roses also have a disease? Black spot leaves black spots on the leaves and there is a rust colored one too. Roses are extremely prone to this and so in addition to insecticide you need some sort of fungicide – hydrogen peroxide works and I’ve heard compost tea as well.

  3. My ecology teacher said if you don’t do anything, nature will take care of it. Not sure if I could be patient enough for that… did you dump the ladybugs in the evening while the sun was setting? They are more likely to stick around if they are cool and sleepy. Maybe try again?

  4. Stephen–I hadn’t thought about diluting the spray. I haven’t used the spray since April because of the discoloration issue, but that may be worth a try.

    Eileen–it was definitely the spray that discolored the leaves. It left a white, soapy residue that kind of wrinkled the leaves up. My front-yard roses do have black spot, which I’ve been trying to get rid of all spring. I heard that I should use something-sulphate, which I bought, but then I wasn’t sure how to apply it.

    Erin–I actually haven’t tried the ladybugs on my new crop of roses yet; I used them at my last house. I do remember that I followed the directions and put them on at night.

    I have been controlling the aphids by checking all the bushes every day and cutting off affected blossoms and leaves. They are pretty much under control. It’s the black spot that’s bothering me lately.

    I may have to get rid of a few rose bushes and replace them with low-maintenance ferns, lavender, etc. Fifty-five rose bushes take so much time and effort!

  5. Put on a pair of rubber gloves and squish them. It’s very effective. But a bit messy on the fingers hence the gloves.

  6. My house has lots of rose bushes and I have also had serious aphid problems. The only organic solution that ever worked for me was to spray them off with a hose every day for a few days until they were no longer infesting the plants. I think that they just give up eventually and find a easier place to live, like the neighbors roses.

    Penny’s idea sounds like a similar concept, and I think either would solve your problem. I could never get the lady bugs to do the work for me.

    As for the black spot or mildew, sulfur mixed with water seems to work best (well, nasty fertilizer seemed to work even better but also made the plants smell chemy). I just mixed it into a spray bottle, but you have to keep shaking it up as the sulfur settles on the bottom.

  7. Michele, I have had success with this method as well. I actually just flick the aphids off with my BARE HANDS if they aren’t too bad, but I cut the stem off if it’s completely covered. It has kept them under control.

    So, with the sulphur solution, do you spray the entire plant or just the black-spotted leaves? Or do you tear off the affected leaves first and then spray the plant? How often do you spray the plants? I couldn’t find directions anywhere. Black spot is my main rose problem these days.

  8. Rebecca, I didn’t find any directions either so we sort of made things up as we went along. I cut off the affected leaves because I thought they were ugly, and then I sprayed the whole plant. The next time I noticed that I couldn’t see any more yellow sulfur residue on the leaves I sprayed it again. I did this repeatedly until the problem was under control. We have one rose bush that is much more troubled than the rest. It has rust, mildew, black spots AND aphids! I’m guessing that the type of rose it is was a poor choice to plant in the misty, overcast climate that is the pacific coast.

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