Thank you for your question about drip irrigation. An underground irrigation system can be very beneficial in reducing fungal disease in the rose garden and helping your roses thrive.

Many fungal diseases proliferate in warm wet conditions. Fungal spores present on the plant germinate when wet and then disease is transmitted from leaf to leaf by splashing water. If you can reduce the amount of time that leaves remain wet, you will reduce the germination and transmission of fungal disease. The fungal spores that produce black spot disease, for instance, need to remain wet for six hours to germinate.

Begin by watering by drip irrigation (or hand water at the soil level without splashing on the leaves). Water in the morning, when the plant will have the most hours of strong sun ahead of it to dry off any errant splashes (and also to make use of the water through photosynthesis). Keeping plants uncongested and exposed to air circulation will help speed the drying of leaves after rain. Plant roses in areas that receive strong sunlight. Keep in mind that high humidity will slow evaporation making these measures even more important in seasons and areas of very high humidity.

Here's the pros, cons and how to's of drip irrigation from Colorado State University Extension.

Watering Roses is discussed in these articles from American Rose Society in these articles about How Often To Water Roses and Keeping Roses Healthy in a Drought. You can read more about caring for roses and avoiding problems in our Guide to Rose Problems.

Courtesy of NYBG Plant Information Service