Question
Vancouver, BC,
I have a nice row of cedars, 5 years old, 10 feet tall, growing like mad, well watered. Do these need to be sprayed and if so, when, and with what? I have sprayed them every spring with malathion, is this a waste of time? I heard these shrubs can get spider mite which makes them die. Today (Thanksgiving Sunday) there is a lot of worrisome dead undergrowth - is this normal for the fall? I fertilize them in the spring with composted grass/vegetables.

Answer
Hello Dennis

Spraying your Cedars with malathion will get rid of a pest called the Cedar Aphid, though as your trees get taller this may be impractical.  The aphids may cause some of the foliage to yellow and fall, but doesn't usually do very much damage.

Red Spider Mite is more usually seem on plants that are grown 'under glass', i.e. in a glass-house or sun-room, where the air may be very dry (this pest loves those dry conditions!), so it shouldn't be a problem outside.

Dead undergrowth - I'm a bit puzzled by this.  Do you mean the inside of the trees or the ground under the trees?

Cedar is very susceptible to Honey Fungus and if you have seen any mushrooms growing around or near the trees during the past 2 or 3  falls, this could be a problem.

I'm going to suggest that you go back to the AllExperts gardening menu and click on 'Plant Diseases' where you will be able to find an Expert who can fully explain what you should look for to identify this problem and what you should do about it.