Now we’ve ascertained the necessity of spraying roses, let’s look at a few basics. If you have just a few roses, even if you spray them regularly, the amount of spray you are handling/inhaling will be small enough not to worry about. If, however, you have say 20 roses or more, there are precautions one should sensibly take. Avoid direct skin contact with the spray at all times, but especially in its undiluted form i.e. put your gloves on before you mix the spray, and use rubber gloves which are totally waterproof (and cheap) not gardening gloves. Cover all the skin you can, wear long pants and sleeves and a hat. Cover your mouth and nose with something to prevent inhalation.
You can go all out and buy a proper spraying mask from a farm supply shop, or buy cheap disposable paper masks, which are better than nothing. Or, you can do what I always did (until I went all out and bought a proper spraying mask from a farm supply shop!) and tie a hanky around your face.
Whatever you do, you are going to look stupid, and suitably scare any visiting children, but such is life. When I’m finished spraying, I always have a shower and change my clothes, but then I have 300 roses. So read the precautions and make a sensible decision for you.
Next on the agenda is the spray unit. By far the most user friendly (we’re not counting motorised options) are the pump sprays with detached arms. These come in sizes from 2-15 litre. You can choose the size suitable to your garden. The bigger ones come as backpacks and are easier to manage, especially if they’re not full! On the other hand, for a few roses, a pair of rubber gloves and a spray’n’wipe bottle will do the trick. It’s just a lot harder to get under the leaves with a spray bottle that relies on gravity!
Now, what to put in the sprayer. First ascertain which diseases/pests are prevalent in your district. If you know Downy Mildew is a problem, don’t wait for it to appear – spray before it does, as most sprays for fungus prevent rather than cure. You may need to use more than one brand of spray as they don’t all attack all the relevant diseases. If you alternate between them, say every 2 weeks. and the disease hasn’t got out of hand, this should be adequate protection.
If, however, the disease has got out of hand before you discover it, or have time to address it. you may have to use the same fungicide 2 or 3 times at say, 10 day intervals. Most of the modern fungicides are systemic, i.e. they get absorbed into the plant’s system, and protect from within. The beauty of this concept, is that so long as the plant is adequately doused, it doesn’t matter too much which part. Old fashioned, non-systemic sprays must be sprayed under each leaf, where the fungus attacks, to prevent infection.
Insects and Mites
Insects and mites present quite a different picture. Here prevention is not really possible, unless you want to constantly spray all your roses in case an aphid appears. Many of the broad spectrum sprays, especially those aimed at the amateur gardener, contain an insecticide which will kill some insects. So read the labels carefully and work out your spraying program from there. You may need to mix 2 sprays together, that’s okay, most of them are compatible, but avoid using two that prevent the same disease as this is a waste of money, and spray is quite expensive.
Specialty rose garden centres and farm supply outlets usually have a better selection of sprays. The staff should include someone “in the know”, who can help you with specific local problems.
In the late winter when your roses are relatively dormant, and you have pruned as much as you are going to, is the time when everyone, even those non-sprayers, should spray with conqueror oil. This is not a poison, but a smotherer of dormant pests (including scale).
In a normal climate, this is followed 2 weeks later, by a spray with lime sulphur. This practice is fine if you want to put your roses to sleep for a few weeks, but not if you’re hoping to get some late winter blooms, as it makes all the foliage drop off. It is only meant to be carried out before the new leaf buds break out. In my garden this happens at a different time for each rose. This would be an individual and therefore very time consuming practice. Instead I keep spraying the roses throughout the winter, but at less regular intervals.
Lastly, remember all living things can build up immunities to poison, so change your type of spray from time to time. Either have two different chemicals going, which you alternate, or else when one bottle runs out, replace it with a different brand. Now on with the specific nasties.