Any rose, whether bush, tea or floribunda, needs at least a solid 6 hours of direct sun exposure each day to flourish. More is even better. However, you can still grow roses in areas of limited sun. They need lots of water, but not so much to give them "wet feet". That is, the ground around the plant shouldn't be mushy but should remain damp. A mulch of some kind helps in maintaining the moisture. I like a shredded bark, since it comes various colors and is relatively inexpensive. Additionally, the roses should be fertilized each 3 to 4 weeks. Use one mixed for roses. Here in the U.S., the best bet is Miracle Grow for roses. Finally, check for spider mites and black leaf. Spider mites are very small black to reddish bugs on the under sides of the leaves. Black Spot is a fungus and grows up the plant from the bottom. Black Spots (clever, no?) appear on the leaves and then they turn yellow and fall off. There are several sprays and dusts that do a good job of controlling both. I like anything with Neem Oil since it also puts a nice shine on the leaves. Don't give up... and best of luck!