Male butterflies need certain minerals found in mud for them to be fertile. They engage in a behavior called "puddling" when they find a little mud puddle and are in need of said minerals. They gather in groups and sip up the muddy water. So, the water in the butterfly garden should be muddy water with lots of solid surface area for butterflies to alight. A plant saucer filled with rocks and dirt then watered until a thin layer of water is over the dirt and some rocks are completely above the water is good for this. Place in a sunny location.

I had the joy of seeing a young swallowtail butterfly as it first unfurled spirally wrapped wings, pump them until they filled with fluid and stiffened. The cutie flew a tiny circle, landed, rested and then took off over the roof. It took about 3 hours.

This happened in a part of my garden full of bronze fennel. I grow it and parsley specifically for the caterpillar of the swallowtail butterfly. They are common in my area. Fennel and parsley, dill are biennials and will form a sort of volunteer perpetual herb garden if allowed to go to seed over open and loose soil (not too much mulch or the seed won't germinate).