How to build a butterfly garden:
Types of plants that attract butterflies:
Butterfly gardens are easy to create. Gardeners should plant both nectar plants to attract and feed adult butterflies as well as butterfly host plants on which the adults lay eggs. The leaves of butterfly host plants serve as a food source for caterpillars, so if you see that your butterfly garden is being munched, don't spray insecticides! A well chewed butterfly garden is (as Martha Stewart says) a good thing. Growing both butterfly host plants and nectar plants is guaranteed to sustain a large butterfly population in your garden. Both the butterflies and the butterfly garden plants will appreciate a sunny site that is protected from strong winds (if you had to lug around giant wings all day, you would too).
Butterfly garden features:
In addition to plants that attract butterflies, serious gardeners will want to add other features such as flat rocks (or bare patches of ground) in sunny spots for butterflies to bask upon (that is what they do in the morning instead of drinking coffee). Plus, small piles of brush within the garden help butterflies to hide and escape heat, rain and predators...so don’t keep your butterfly gardens as neat and tidy as you would a formal garden. You may also want to add a butterfly house (like a bird house but with narrow slots that only butterflies can pass through) where butterflies can rest, protected from heat, wind, rain, and predators.
Butterflies also need a source of water to drink. Bird baths are too deep for them...they prefer shallow puddles of water with mud, sand or rocks, which provide salts and minerals for the butterflies. You can turn a bucket, bird bath or any decorative pot into a butterfly watering hole by filling it with gravel or sand and keeping it continually moist. Butterflies will suck the water out from between the rocks with their straw-like feeding tube. Keep their drinking water cool by partially burying the water pan in cool soil. Some butterflies also like cut fruit which they eat after it ferments…feel free to toss your old apples and bananas into your butterfly garden. Those with horses may know that some butterflies feed on manure so sling some around your butterfly garden (preferably in a hidden spot, and preferably downwind).
Why are butterflies attracted to certain plants?
Choosing the best plants that attract butterflies is a lot easier if you understand butterfly anatomy and biology. Butterflies cannot focus their eyes so the world appears blurry, thus they are more attracted to mass plantings of brightly colored butterfly flowers than those planted singly. Butterfly eyes are sensitive to different colors than humans and they see blue, purple, green, yellow and orange much better than they see red. They can also see ultraviolet light and many butterfly flowers have distinct patterns that only appear under ultraviolet light. Butterflies have a great sense of smell (via their antennae) and so fragrant flowers are a favorite. Butterflies reproduce by laying eggs on the leaves of butterfly host plants so it is best if you do not remove spent leaves right away as you may inadvertently be removing butterfly eggs. It’s best to leave perennials standing over the winter, or at least to pile them into a loose pile in some out-of-sight corner of the butterfly garden.
NC Cooperative Extenstion - 4H article on butterflies
JC Raulston Arboretum
Durham Museum of Life and Sciences
Missouri Botanic Garden
U. of Kentucky Entomology
The Butterfly Site - Butterflies
The Butterfly Site - Food
The Butterfly Site - Creating a butterfly garden
Gardens With Wings - Host Plants
Gardens With Wings - Nectar Plants