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Gardening for butterflies
What do butterflies need? Just like us, they want food, shelter, warmth, and a suitable place for a family.
A butterfly looks for plants that are good sources of nectar to give it the energy it needs for flying — to look for other nectar plants, to find a mate, to patrol and chase off intruders, and to find the right plant on which to lay eggs. Besides nectar, some butterflies also feed on rotting fruit or vegetation.
Butterflies also need minerals, which they get from damp soil or sand, or manure. After rain, you can often see Tiger Swallowtails gathered round a mud puddle in a dirt road feeding on the mineral salts.
Butterflies particularly like plants that have flat pads, umbels, cones or spikes. The flower heads of all these plants are made up of tiny flowerlets. A butterfly can probe each one without moving about very much and using unnecessary energy.
The ideal butterfly garden is in full sun and sheltered from the wind. Sun is important because butterflies need to warm up after cooler overnight temperatures. You don't see them on the wing much before mid-morning when the sun is stronger.
Stones are useful in the garden because they absorb the sun's heat and provide basking spots where a butterfly can "charge up its battery."
MAKING A GARDEN
Most people do not have ideal sites. However, just choose the sunniest spot in your yard, put in good nectar plants, and the butterflies will come. All the plants listed below are quite easy to grow and do not require special conditions. Although Joe-Pye Weed and Swamp Milkweed prefer moist soil, they will grow in dryer conditions as well.
Violets are among the earliest nectar plants to flower, followed by arabis, forget-me-nots, chives, sweet rocket, and dianthus. Then come the summer yarrows, daisies, mallows, milkweeds, coneflowers, and rudbeckias. Finally, Joe-Pye Weed, goldenrods, and asters.
Besides good nectar plants, butterflies need special host or larval plants on which to lay eggs. After the eggs hatch, the caterpillar or larva spends its life eating the leaves of the host plant. As it grows bigger, it sheds its outer skin four to six times before becoming a chrysalis. Finally the adult butterfly emerges and the cycle may be repeated, depending on the species and time of year. On average, from egg to adult takes about a month.
Not any plant will do for caterpillars. Each butterfly species has its preferred host plants. Female butterflies search for these particular species on which to lay their eggs. You can often see one flying from plant to plant, landing briefly on a leaf, then taking off again. The butterfly is "tasting" the leaf through sensors on her feet to see if she has found the right one.
Many of these host plants are trees like birches, poplars, and willows (see list below). These may already be growing in your neighbourhood and need not be considered unless you are starting from scratch in a new subdivision.
The two host-plant families that are easiest to provide are the various milkweeds for Monarch butterflies and fennel, dill, parsley, or other members of the carrot family for Black Swallowtails. Both of these plant groups are also extremely good nectar sources for all kind of insects, especially the beneficial ones that eat or parasitize the pests in your garden.
Other attractive host plants are violets for fritillary butterflies and pearly everlasting for the American Painted Lady. If you have a large garden or an out-of-the-way corner, you might also put in a nettle bed for Red Admirals and Question Marks and thistles (Cirsium) for Painted Ladies.
The more variety you have in your garden, the more insects, including butterflies, you are likely to attract. By using wildflowers such as Queen Anne's Lace, goldenrods, and Black-eyed Susans among your garden plants, you can offer the widest choice possible. If you have grass, you could also have a wildflower lawn that includes creeping buttercups, thymes, and clovers.
Butterflies have been declining in number due to a combination of factors: bad weather, development, and pesticides. Cool, wet summers are not ideal for butterflies, and very hot, dry ones may limit the abundance of plants due to drought. Butterflies can overcome unsuitable weather conditions, but not pesticide spraying or loss of habitat.
To help restore butterfly populations, we need to recreate suitable habitats for them. Each garden for butterflies is a tiny island on its own that a butterfly might miss. The more such gardens there are, the greater their chance of being effective. Neighbours on a block might join together to contribute different parts of a combined habitat for several species. Please join us and become one of the butterfly gardeners of the world!
PLANTS FOR BUTTERFLIESNectar sources (* best; A = annual; P = perennial; Sh = shrub)