Greetings, in order to attract and keep butterflies on your site you
need to plant both
nectar and host plants, thereby, providing both food and shelter.
There is a free butterfly online garden course located here.
What do you need to know? I am in the middle of planting mine down here
in Texas and have done tons of research on what the butterfiles and
hummers like. I'd be glad to help if I can.