Question
i live in Karachi, Pakistan. the climate is generally hot, around 30-40 between April to June and then again in September to October.November- February stays around 20-30C.

i have planted various rose plants in big pots. they don't give much flowers during any time of the year. please help me know how to get more flowers from these plants

Answer
Roses love to have ( and grow better) when their roots are cool. The rose makes long thick roots to anchor the bush, then they grow tiny, thin hairlike roots which are called feeder roots. These are the most important ones because they take up the nutrients plus the water. if a container gets hot, feeder roots will suffer or die. Then the bush doesn't get what it needs to be a strong grower. You were wise to plant them in large pots but where you have very high temperatures, rose really only need about 5 hours of full sunshine. I know the rose books say they should have all day sun but that has been proven not so. When you grow roses in a climate such as yours, the sun is stronger and the plant does not need as much as if it was grown in a cool European climate. If it is possible to place your pots in part shade your roses will do much better. Because roses love cool roots, if you could place some sort of mulch on the top to help keep the top of the soil cooler. Now that it is cooler, if you place them in part shade and cut your roses down to 12 inches, they will have a new start.