-I heard that some chile pepper plants are perennials, are they, and if so, which ones?
-All pepper plants are perennials if the conditions are favorable (no frost or freezing temperatures). Southern California and Florida (here in the continental U.S.) are probably the only places where you can grow peppers as perennials.
-I have a small chile garden and have noticed that many of the jalapeo chiles get black or dark areas on them as they near maturity. Other than these spots, the chiles seem fine. Can you explain what these are? Is there anything I can do to prevent them?
-This purpling or blackening is due to direct sunlight, and can be avoided by producing a bushier canopy that shades the pods.
-Are ornamental varieties of chiles poisonous?
-There are absolutely no varieties of peppers that are poisonous; all capsicum species are edible. Some of the ornamental varieties just don't taste very good, while others are extremely hot or pungent, which may lead to this misconception; however, there is an ornamental plant called a False Jerusalem Cherry, botanical name, Solanum Capsicastrum, which is poisonous and not intended for consumption. It is not a chile plant, only a relative.