Question
Hi Lynette, I live in Perth, Western Australia and I have inherited a garden with...wait for it...55 rose bushes! Some are in better states of health than others.  It is Autumn here now, but over summer we had a lot of problems with black spot etc, and now some of the roses are covered with aphids and other bugs.  I have used a chemical spray but have young children and would prefer to use organic methods.  I fertilise using castings from our worm farm and the roses seem to love this, we also mulch and plan to use a lime sulphur solution in winter when there are no leaves. What sort of spray should I use on my roses? Can I make one myself? And how often do I need to do it? Thanks so much, I really want have a thriving rose garden but I'm so new to it all!

Answer
Organic rose growers, as well as commercial ones, have had great success with the dormant lime sulphur spray that is used on trees. But there is one for roses and it seems to kill the fungus. You have to do it now and then again before they leaf out. Just buy the spray for the trees and use the one for shrubs on the package. Aphids are the easiest to get rid of. The eggs are laid on the tip of the rose canes and when the eggs hatch they feed on the tender new growth. You can knock them off with a spray from the water hose because once they are knocked off they are too weak to climb back up. The stay on the soil and the birds eat them up like candy. If you get mildew then 1 tablespoon of baking soda to 1 quart of water sprayed daily, until there are no signs of the mildew.
Black Spot spores float around in the air and when it rains or is windy are knocked down to the ground. If they land on a rose leaf then they start their life cycle. There is not one Black Spot fungus but about 8 strains, so sometimes when you solve the problem with one spray then it doesn't work on another type of spore. However what the commercial growers have found out, if you spray a liquid fertilizer as a foliar feed, such as a fish one, it will change the PH of the leaf and make it inhospitable for the fungal spores. Needless to say the rose also benefits from the feeding.
I would, if your roses are looking scruffy, cut them back hard this fall, right back to 18 inches. Take out any canes that are thinner than a pencil. If they are older roses and have a few thick gray canes, then take out one to make room for new canes to come up from the base. Next fall take out another old gray cane. Most modern roses only need about 5 good healthy canes. 55 rose bushes should keep you fairly busy but only in the spring and fall when they need attention. Hope they left the name tags on them.