Fungi & Flowers

Gray Mold

• The most common fungus to find in a floral garden is gray mold. When temperatures are cooler and rainfall present, flowers become more susceptible to gray mold infestation. Old and dying leaves or flower petals display a fuzzy gray substance that starts as a water spot. Remove diseased flowers from your garden if you notice signs of gray mold. Spray beneficial bacteria on infected and uninfected plants alike and avoid overwatering flowerbeds. Make sure flowers have enough circulation between them so that the airflow dries excess moisture.

Black Spot

• Black spot most commonly affects roses but attacks other flower species as well. Temperatures cooler than 85 degrees and moisture lasting at least seven hours are black spot's main causes. Planting flowers in open and sunny areas with warmth and air circulation prevents this disease. Prune infected leaves and rake away fallen leaves that house the fungus. Choose resistant rose species at your garden store and spray susceptible plants with neem oil every 10 to 15 days during the growth season.

Powdery Mildew

• Powdery mildew is easy to identify because foliage, stems and flower petals show a powdery, white substance on them once the fungus is present. The infected foliage begins turning yellow or brown, depending on the infection's severity. Powdery mildew is not immediately fatal to plants, but it weakens the plant to the point that does not bloom. Both perennials and annuals are susceptible to powdery mildew infections, but the species vulnerable are zinnias, verbena, snapdragons, lungwort, bee balm and garden phlox. Purchase resistant species of flowers and use horticultural oil during powdery mildew season from June to early July.

Fungi's Spread

• Fungi spread through water and wind. Since most fungi grow in wet conditions, control the soil's moisture by controlling your watering. Use drip irrigation or water with a hose directly at the flowers' base, rather than spraying from above. Water your plants in the morning so the sun dries up excess water and flowers do not sit overnight in moist conditions.