Life wasn't meant to be easy, and for rose gardeners the rule is proven in pests. Sydney has a different mix of pests compared to Europe and America. Here's the hit list of pests and what to use for them:
Common the world over, these little green insects gather on rose buds and the tips of new stems. They suck on the rose sap, draining the goodness that would otherwise go to the bloom or the growth of the plant.
Aphids are the easy-beats. Almost any pesticide will kill them. Pyrethrum sprays, garlic sprays, soap sprays, white oil, Mortein House and Garden - take your pick. Even a good jet of water will dislodge them.
If aphids keep coming back after you spray, I recommend Rogor or Folimat. These are systemic pesticides, entering the sap of the plant after you spray. The aphids then suck themselves to death. Effects last several weeks, even after rain. Aerosol and concentrate sprays are available at hardware shops, nurseries and K-mart. Watch out though - these chemicals are organo-phosphates and they need careful handling.
I use Rogor, which has been around for decades and is possibly the cheapest pesticide you can buy. Isn't it wonderful when patents run out? :)
Similar to aphids, only smaller and often found sucking in the flowers themselves. Not a problem in Sydney. Equally easy to kill, but you really need a systemic insecticide because gentler contact sprays can't reach them inside flowers.
Barely visible to the human eye, these things congregate in thousands on the underside of the rose leaves, sucking goodness from them and leaving them looking 'sand-blasted', like this:
Serious infestations can kill plants. You can spot a bad infestation when you see webbing on the underside of the leaves, especially on the lower branches. Mites tend to pick on certain single bushes - one plant can be infested but the bush next to it can show no signs at all.
A short term deterrent for mites is using a soft spray watering wand to soak the undersides of the leaves when you water. Like most spiders, these creatures hate getting wet. A good wetting will disrupt the adult mites, but unfortunately not their eggs. Wetting the foliage has its own potential problems in spring and autumn, too, because it can promote fungal diseases.
A long time ago (in a galaxy far, far away) the systemic insecticides like Rogor and Lebaycid did a good job of killing spider mites. Unfortunately mites have evolved resistance over time and most organo-phosphates are now useless. The only remaining variety that advertised mite control (until recently) was Folimat, and even then it warned about resistance in some populations of mites.
Spraying a contact spray on the undersides of the leaves is the only good way of controlling mites. That's not easy to do - I use a pressurised 5 litre sprayer with a wand that I can direct under the bush. Products to use are:
I tend to alternate between the above three methods. Repeat spraying is needed because you can't get spray on all of the mites in any single dose. Complete elimination is very hard to achieve.
Sydney's possum population loves to chew the soft ends off rose stems. Some garden gurus recommend making the stems unpalatable by spraying them with a bitter mixture of quassia chips and water - I haven't tried this, but a lime sulphur spray does work. A new special purpose spray charmingly called 'Poss Off' is available too.
The only other control is a physical barrier like chicken wire. It sort of defeats the aesthetic purpose of having a nice rose bush though!
Don't even think of killing spiders or ladybirds on your roses. They're doing natural pest control for you. Praying mantis are rare in Sydney but they're very worth protecting too.