Tea roses are a thin-stemmed variety of rose with loose-formed flowers that measure two to three inches across. The blossoms grow singly or in clusters of two or three. The blossoms might be doubles with as many as 50 petals, or semi-doubles, with 10 to 20 petals. The tea rose does not tolerate frost and comes in a variety of colors such as lemon yellow, salmon, clear pink, white, buff and apricot.
When tea roses fall victim to canker it is difficult to successfully control this disease, and if the infected tea rose is left to mingle with other rose bushes, the disease can spread. Brown, dead spots on the cane is a sign of canker. When the brown spots encircle a stem it stops the flow of nutrients, killing the leaves and buds above the area, and eventually killing the plant. Canker is caused by fungi that typically enters the plant by cuts made too far above the bud eye and by using un-sanitized gardening shears.
Crown gall is a bacterial infection that can be best treated in the early stages of the disease. Signs of crown gall include growths along the root and soil line. The cause of the bacterial infection is often the result of the plant being injured, perhaps from a stray gardening tool. If left untreated, the plant will become stunted and will eventually die.
A tea rose with rose blackspot will show signs of black spots on the leaves, with yellowing on the area around the spots. Eventually the leaves die and fall off prematurely. Tea roses in humid weather are more susceptible and the disease is spread by spores, which are carried to other plants by water splashing, either through irrigation or rain.
Rust and Powdery Mildew
Hybrid tea roses are vulnerable to rust and powdery mildew. The symptoms of rust are wart-like growths on the underside of the leaves, which cause the leaves to die. Powdery mildew is one of the most common rose diseases and it appearance resembles the name, in that a powdery like substance coats the buds and canes of the rose bush. Leaves shrivel and die and the tender buds wither, before having the chance to open. Humidity and crowded planting conditions can cause powdery mildew.