I often see these brown buds on my rose plant stems, What are these Brow buds, are these harmful? if so how to prevent/cure these.
They look rather like a form of scale insect - rose scale usually looks white, but living where you do, it's possible other forms of scale are more common. Those flattish brown objects can be removed by using 70% alcohol or methylated spirits and a rag - just moisten a rag lightly and rub it over the firm, thick stems to get them off, but keep it off any soft growth. There will likely also be nymphs, which don't look the same and are quite difficult to see, so after you've removed the brown deposits, spray the whole plant, especially soft green growth (leaves, backs of leaves, stems) with neem oil spray or a horticultural oil spray.