Planting for Healthy Foliage
You can start to ensure healthy leaf growth when you first plant your rose. If you dig the hole for your plant twice the size of the root ball, it will give the roots room to grow without crowding. Crowding of the roots causes less foliage and when wet can cause fungal disease to travel to the leaves. Mix compost in the soil before placing it back in around the roots. The use of a well-rotted mixed animal manure is the best compost to use for rose plants and will help to give good color and thick foliage. You must also place the plants well enough apart to give good air circulation. If the dew or rain is not allowed to dry from the leaves, you will end up with a mildew disease or an insect infestation.
Roses need a lot of water to produce beautiful flowers. They should be watered for long periods of time once or twice a week instead of short periods of time every day. The problem with watering for long periods of time is that most people do not want to stand there and water so they use sprinklers. It is very important to use a drip irrigation so the water flows on the soil and not on the plant's foliage. Wet leaves will eventually turn into diseased leaves. You should also water in the morning so the plant has time to dry out during the day and not remain wet all night causing fungal and mildew problems.
Fertilizing and Mulching
Roses need a phosphorus fertilizer for beautiful blooms, and they need to be fertilized often. A common mistake of beginning rose gardeners is they neglect the fact that lush green foliage needs nitrogen. Make sure the fertilizer you use has a good dose of nitrogen in it for great looking, thick foliage. It must also be balanced with the phosphorus or you will have all foliage and no blooms. You can add to the nitrogen in the soil while protecting your plant from drying out and weeds by using grass clippings as mulch. Grass clippings are high in nitrogen, make a great mulch bed and will compost the soil as they degrade.
Once the flower's leaves die off the plant in July or August, you can prune off any dead or diseased wood and shoots that are crossing over and causing the plant congestion. Cut a few inches off the main stems at a 45-degree angle and leave all short new wood as is. This will ensure a healthy start for the next spring. Take all the pruned wood to the garbage or burn it as there will be fungus and mildew on it. You should also pinch off all dead flowers any time of year and not let them rot on the leaves or branches. Following these steps will prevent disease and give you healthy foliage for your rose plants.