Roses

The only time I will ever be okay with fungicide is early spring when roses are putting out their new growth. Using an organic fungicide I allow my roses to get a few sprits which secures them the rest of the year. It's an early preventative, the rest of the year it just needs proper watering and mulching.
When watering be sure to just wet the ground and not the leaves, wet leaves are what cause fungus and disease to grow.
It's also very important to plant them in full sun where there is good air circulation.

To keep them blooming longer, cut off the spent flowers. I leave them on in fall so the animals can eat the "berries" the roses make.
In spring don't throw away your cut stems, you can root those to make more roses! If you add rooting powder to the ends of them stem after you cut them, then stick them in potatoes they can actually root that way. So don't waste money on new plants!

Throughout the year you can throw your banana peels around them along with coffee grinds. They provide some natural nutrients to the plant. The coffee grinds also help fend off slugs and some other pests. Coffee grinds also ad some acid to the soil the roses love.

Here's are some pictures of my roses.