Attracting Butterflies to the Garden
Color and ultraviolet light
In order to start attracting butterflies, you need to start thinking and seeing like butterflies. "If we were to see like a butterfly, we would look at really bright colors," says butterfly expert Rachel Diaz-Bastin of the Conservatory of Flowers in San Francisco. "Their favorite colors are red, yellow and blue, because those are the flowers that are really bright and advertise that they have sugary water and good nectar for them to drink."
Butterflies also see in the ultraviolet range. A black-eyed Susan is just yellow and black to us but in the ultraviolet range, it's very bright, and that's what butterflies see.
On their wings, butterflies also have ultraviolet light, and that's what they look for in each other. Sometimes when they are selecting a mate, they look for the UV light, not just the colors that we can see.
Those who fly need a place to land, so be sure to provide plants with a perfect perch. Butterflies like flowers with a landing pad because they like to sit when they eat. Think of flowers like yarrow (Achillea), butterfly bush (Buddleia) or butterfly weed (Asclepias).
How do butterflies sip nectar?
If you were to look closely at a butterfly's face, you would not see a nose but a proboscis. A proboscis is just like a big drinking straw. It's usually coiled when the butterfly is at rest, and when it's ready to drink, it uncoils the proboscis slowly. Butterflies' noses are actually in their feet; they have smell receptors in their feet, legs and antennae.
Offer them water
Long days spent migrating or just flitting around the garden can make a butterfly thirsty, so make sure you offer them something to drink. Set up a butterfly bath — which is like a birdbath with sand in it. Put a little bit of water into a shallow bowl, not so much that they can drown in it, but just enough so the sand is wet. They'll do what is called puddling; the males try to soak up nutrients like salts from the water and the sand. The males need sodium to get the energy in order to mate with the females.
Plants that attract butterflies
Some of the many plants that butterflies prefer include those that you wouldn't ordinarily think about. Gardeners generally harvest carrots before they go to flower or they pinch the terminal growth of coleus so it gets bushier rather than let it flower. But if you're trying to attract butterflies, it's best to allow these plants to flower. If you have a vegetable or herb garden, plants in the Umbelliferae family are great attractors and sources of pollen; they include parsley, celery, coriander, fennel, lovage and dill.
By creating a butterfly sanctuary, you may find purpose for plants you thought you needed to get rid of. "You know gardeners battle weeds all the time, but the truth is there are a number of great weeds, like clover and Queen Anne's lace, that attract butterflies," says Rachel. Because these plants can make your garden look weedy, dedicate a spot somewhere in the yard just for these plants. Milkweed is a butterfly favorite, so you don't want to pull all of it out because that's what's going to attract monarch butterflies when they make their annual migration.
If you've tried everything and butterflies still aren't knocking down your door, you can offer them commercial butterfly nectar that you can buy online or in a garden shop. "That's actually what we feed our butterflies to supplement their diet," says Rachel. "It gives them that sodium and protein that some butterflies need, not just the pure sugar water that some butterflies drink exclusively." Many butterfly feeders come in bright red and yellow, which are the colors that butterflies are attracted to most.
Nesting sites and metamorphosis
Many butterflies lay their eggs on plants. For example, swallowtail butterflies sometimes lay their eggs on flat-leaf Italian parsley. Because the caterpillars eat the parsley, overplant the parsley and have some plants dedicated for cooking purposes and some dedicated just for the caterpillars.
Designating a specific area in your yard with extra food for butterflies can allow you to witness the process of metamorphosis. Complete metamorphosis occurs in four stages. It begins with an egg, then the egg hatches into a larva. At this stage, it's basically an eating machine and doubles its weight over two times every single day. If a human baby were to do that, it would weigh about two tons in a week. Since they're constantly eating, the caterpillars can do some damage to plants in your garden. The truth, though, is that with most native butterflies, the caterpillars don't eat enough of a plant to actually kill it but rather they may defoliate it. Then next season, the plant will regrow those leaves.
Once they fill up their reserves with food, the larvae go through the pupa stage, where they essentially hibernate inside a cocoon until they emerge as a butterfly. When they reach this stage, they're very beneficial to the environment, because in the process of visiting flowers, they pollinate them.