Flowers

Rose: Black mold

Rose: Black mold categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Biology Black mold primarily affects material used for propagation. The fungus grows on cut surfaces, such as at the contact points between rootstocks and scions and rootstocks and bud shields. This causes graft failures. A gray-white fungus growth is the first symptom […]

Rose: Black spot

Rose: Black spot categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Rose black spot on leavesPhoto by: R.S. Byther Biology Black spot is a very common fungal infection of the leaves and canes of roses. Round black leaf spots (sometimes with fringed or feathery edges) may be accompanied by leaf yellowing and leaf […]

Rose: Botrytis bud and twig blight

Rose: Botrytis bud and twig blight categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Botrytis on rose canesPhoto by: R.S. Byther Biology Botrytis can infect stems and flowers, including stubs left from pruning or flower removal. Infected tissues are usually covered with a fuzzy, gray-brown growth. Infected flower buds may not open, and […]

Rose: Brand canker

Rose: Brand canker categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Rose brand cankerPhoto by: R.S. Byther Biology Brand canker is a fungal disease that often infects plants in the winter, especially when winter protection of roses keeps the canes moist. Initial symptoms of infection are small dark red spots on the canes. […]

Rose: Bullheading (cold damage)

Rose: Bullheading (cold damage) categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Rose bullheadPhoto by: R.S. Byther Biology Bullheads are the most prevalent when temperatures dip to 53-59 degrees Fahrenheit during early flower development. Low temperatures appear to alter metabolic activity, which results in the abnormal appearance of buds and resulting flowers. Flower […]

Rose: Common canker

Rose: Common canker categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Rose common cankerPhoto by: R.S. Byther Biology Common canker is a fungal disease that infects plants through long stubs left by improper pruning or through other wound sites. Small yellow or reddish spots appear on canes and gradually enlarge. Later, the centers […]

Rose: Crown gall

Rose: Crown gall categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Crown gall on crown of rose.Photo by: R.S. Byther Biology Crown gall on roses usually occurs at or just beneath the soil surface. It may also be found on stems and roots. Young galls appear as a soft thickening in stems or […]

Rose: Downy mildew

Rose: Downy mildew categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Downy mildew on rosePhoto by: R.S. Byther Biology Downy mildew can affect leaves, stems, flower stems, and flower parts. The infection is usually found only on young growth. On leaves, symptoms include purplish or brown spots, usually between veins, and yellow leaves […]

Rose: Powdery mildew

Rose: Powdery mildew categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Powdery mildew on rosePhoto by: R.S. Byther Biology Powdery mildew is a fungus attacking leaves, stems, and flower parts. Usually young growth is most severely affected. Reddish, blister-like areas on the upper side of leaves are followed by powdery white growth, which […]

Rose: Rust

Rose: Rust categories: Flowers Ornamentals Rose Rose Diseases revision date: 2023-02-07 12:00 Rust on rose leavesPhoto by: R.S. Byther Biology Rust usually is first noticed as clumps or pustules of red to orange powder on the lower surfaces of leaves. The upper surface may also show yellow, orange, or brown spots, corresponding to the location […]