Roses in the garden can be infected with a variety of bacteria, fungi, and viruses, leading to diseases like powdery mildew and rust. Roses may also be damaged by nutrient deficiencies and other environmental problems.

Our Pest Notes: Roses: Diseases and Disorders was recently updated by University of California experts John Karlik, Deborah Golino, and Maher Al Rwahnih. This free publication provides an integrated approach to managing rose problems that includes careful variety choice, proper irrigation, correct pruning, and sanitation. Although some rose enthusiasts might consider regular application of fungicides a necessary...

Days are getting shorter and evenings cooler as winter approaches. Sweater weather also means a change in the to-do list around the yard.

Here are a few things to consider when preparing your landscapes and gardens for winter.

Frost

• Protect sensitive plants from cold injury when freezing or frost is predicted. Cover plants with cloth or a similar material at night, leaving the covers open at the bottom so heat from soil can help warm plants.
• When frost or freezing is expected, irrigate dry topsoil at least 3 days before the cold weather to increase the soil's ability to retain...

Winter is an ideal time to prune deciduous fruit and shade trees, since the trees are dormant and you can more easily see the tree canopy. In many cases, pruning can also help prevent or control certain insect and disease problems.

For help with pruning, visit the UC IPM web page called Pruning fruit and shade trees and shrubs.This page provides links to plant-specific pruning information for fruit trees, nut trees, landscape trees, and others. You can also find links to diseases and environmental disorders that commonly affect fruit and shade trees, as well as additional information on the topics of landscape management and videos on...

Most people think about pruning fruit trees during the winter since the branch structure is most visible and winter is considered the traditional time to prune deciduous trees. Actually, pruning fruit trees mainly during the growing season is a good practice and with some species such as apricots and cherries, pruning between September and March in northern California could lead to detrimental canker diseases.

Cherries, apricots, and a few related species are particularly susceptible to fungal and bacterial canker diseases, including Eutypa dieback, Botryosphaeria canker, and bacterial canker. Pathogens can be spread by rain or tree wounds – such as pruning wounds – during wet weather; subsequent infections spread...