Hi,

Try lemon scented dish detergent in your spray water to control the spider mites on your Brugmansia. Is there any way you could order lady bugs, or is it too cold in your area. When you say 'put to bed', what exactly does that mean? Are you cutting the Angels back to the ground and covering them with pine straw or leaves, etc., and taking your cuttings into a warm area? If so, you must get rid of the spider mites or they will only multiply out of proportion. Please let me know more about your conditions in your area. Why can't you get systemics?

Here is a link that might be useful: Brugmaniac