What is this and how do I treat it?
Something on My Roses
I've got some store bought spray I can use on the aphids but I might need to buy some more to take care of the hordes!
The ants is another clue of aphids. The ants milk the aphids kind of like dairy cows are milked for their milk. Where there are lots of aphids, there will usually be lots of ants sooner or later.
Thanks for this, it was what I thought but I got confused by the colour of the bugs, i.e. white instead of green. Also, the plants are covered in ants!
It looks like you have an Aphid Convention going on there on your rosebush!! With that many of them, I recommend getting a good insecticide and spraying your roses down well with the insecticide at least twice. Many insecticides will take out aphids so read the label on those available at your local garden center or nursery. If there were just a few, a stiff spraying with water for 3 to 5 days would send them packing too. Here is a link to an article on this subject for you as well: https://www.gardeningknowhow.com/ornamental/flowers/roses/aphids-on-roses.htm