Question
I am downsizing my rockery and my weeding. Is it OK to use a layer of cedar
sawdust and top it with cedar chips for a nice longer lasting mulch or will the
cedar kill my flowers and shrubs ?  Thank you !   Anne

Answer
Cedar is non-toxic to people, and some holistic herbalists recommend its oils for personal use, although some sensitive persons have reaction to it.  It *MAY* contain toxic phenols harmful to rodents & poultry, but I'm not 100% positive, as I'm not a Veterinarian.  

As to plant toxicity, it is used extensively to keep weeds at bay, as its ground-shading properties keep seedings from germinating successfully.

I have not seen or heard of it having an damaging effect on larger plants (like raising pH of the soil, causing die-back, etc.)...So go for it!  ~Marc