Holly bushes are among the most resilient types of ornamental landscape plant. They can be planted in a variety of climates and conditions if treated and maintained properly. However, holly bush diseases can occur, and can be fatal if left unchecked. There are three common causes of holly bush diseases, and once these causes are addressed the diseases are easily prevented.
Holly bushes diseases can be caused by insect, fungal and environmental problems. The most common insect problems that cause holly bush diseases include mites, scale, leaf miner and aphids. The most common fungal problems found on infected holly bushes include Tar Spot and cankers. Environmental problems for holly bushes can include wind conditions, poor soil and poor placement.
Treatment varies depending on the type of disease infecting the holly bush. Treatment for insects usually includes use of insecticidal soaps, insecticides or destroying the affected leaves or branches. Environmental diseases can be treated by adjusting the soil content, moving the holly bush or providing coverage such as wind breaks. Fungal diseases can be treated with the use of fungicides, pruning or destruction of the infected leaves and limbs.
A good way to prevent holly bush diseases in landscaping is to choose highly resistant varieties of the bush. Proper drainage is another means as poor drainage can cause both overly dry and wet conditions that can lead to infection; the use of raised beds helps provide drainage and good soil conditions as the area can be customized for holly bushes. Promptly removing infected leaves and branches helps prevent further infection; destroying infected bushes, leaves or branches continues this solution. Proper spacing also is used as a prevention against infection of surrounding holly bushes.
Holly bush diseases can disfigure or kill infected plants. The most lethal of holly bush diseases are the fungal varieities such as Tar Spot or Bot Canker which can kill holly bushes within one season. Insect related diseases can cause serious damage or kill the host bush if left untreated. Environmental causes can take longer to affect holly bushes but can cripple holly bushes and lead to possible death.
The most resistant holly bushes are the Chinese and English holly. Both the American and Yaupon varieties are moderately susceptible to holly bush diseases. Japanese and Blue holly varieties are the most susceptible of the holly family to becoming infected.