Military illumination flares are "defence explosives" as defined by section 150 of the Explosives Regulations, and are not approved explosives for civilian use. They are only approved explosives for transportation by common carrier. Possession of military ordnance of any sort is a good way to get your name on CPIC.
Road flares are a cheap, easy source of ground illumination, but burn red. There are also various consumer fireworks you can buy that have an illumination component as part of their effect. I'd start with flares and see if they give you the type of effect you want. concept_8's caution about fire hazards is quite valid; pay attention to it.