Wildlife in My Backyard
Some people may not be enthusiastic about attracting butterflies and all of their life cycle stages to their garden, but butterflies add colour, movement and beauty to the garden. They are also beneficial pollinators for many of our favourite flowers.
Butterflies are classified under Lepidoptera in the class of insects, and are found in many different habitats throughout North America. Many butterfly species have recently expanded their ranges due to changes humans have brought on through disturbed habitats where native plants and introduced weeds now thrive. Some of the beautiful species that have expanded include: Black Swallowtail, European Cabbage Butterfly, Clouded Sulfur, American Painted Lady, Monarch, and Silver-spotted Skipper.1
In order to fully understand butterflies and attract them to your garden you must understand their life cycle (Figure 1). With this you can plan your garden to meet their food, shelter, and other needs at each stage of their life cycle. Butterflies begin life as an egg usually deposited singly, or in clusters up to a few hundred, on or near the host plant, usually on the leaf underside. The eggs hatch in 4 to 10 days. Larvae feed on the underside of the host plant leaves, and take from 3 to 4 weeks to turn into a chrysalis, or pupa. However, some butterfly species spend the winter as a larvae, hibernating in the crevices of trees trunks and walls, and wait until spring to pupate. Others, like the Silver-spotted Skipper, have the first eggs of the season develop directly into butterflies and the second brood winters as larvae. It may take from one to two weeks for the pupa to develop into a butterfly, but some like Swallow-tails pass the winter as pupae. Most butterflies live for 2 or 3 weeks, while some live for 10 months or longer. The early spring and summer generations of the Monarch live a few weeks, while the fall generation that migrates south will survive for 6 months before mating and returning north again (the Monarch is the only truly migratory butterfly).1
|Figure 1: Butterfly Life Cycle.1 From the egg the caterpillar or larva hatches. When ready the caterpillar prepares to pupate. The pupa or chrysalis forms and later, emerging from the pupal case to the fully formed adult butterfly.|
Flower nectar is the primary food source for most butterflies and is obtained from many annuals, perennials, trees, shrubs, vines and herbs. Most of the flowers butterflies favour are ones that gardeners choose for their beauty or fragrance. Many are often recommended for attracting hummingbirds, but butterflies prefer a slightly different garden design from hummingbirds. The main difference in a butterfly garden design is that they require open, sunny gardens, since butterflies are cold-blooded and need sunlight to warm their bodies, often flying only when temperatures are at least 60°F. Butterflies need a food source, water, cover from the elements, and a place to spend the night. The environment must be stable and predictable and balancing all the components butterflies require is part of the challenge and art of butterfly gardening.
|Monarch Butterfly on|
|Monarch Butterfly on Cosmos|
Some butterflies, such as the Tiger Swallowtail and Spring Azure, prefer tall flowers, while others stay close to the ground in search of nectar. You should keep the feeding habitats of your favourite butterflies in mind and plan your garden around them. Butterflies are attracted to open areas of grass and wildflowers which resemble their natural habitat. A butterfly meadow can be an attractive addition to any garden. There are numerous wildflower mixes available from nurseries, but you can also harvest seeds from native plants such as thistle, dandelion, knapweed, fleabane, clover, goldenrod, and milkweed. If you are adjacent to a natural area you can extend your garden towards it with native plantings.
The use of container plants can attract butterflies to small urban spaces. Plant impatiens, phlox, ageratum, cosmos (also great food source for the American Goldfinch), daylily, and primrose. A group of container plants massed in one location will attract butterflies more than scattered, individual containers.
|This dwarf cherry zinnia was very attractive to many butterflies and other insects. Pictured left to right is bumblebee, frittilaria butterfly, monarch butterfly.|
|Table 1: Butterflies in our area and their favourite nectar flowers (modified from Arbuckle and Crocker (1991)).1|
|Table 2: Butterfly Flowers.|
You will want to provide the proper host plants once you have adult butterflies frequenting your garden. You can provide enough host plants for the butterfly larvae and still have enough plants for your enjoyment. See Table 1 for a list of host plants.
To protect host vegetables and herbs, such as cabbage, parsley, and dill from being eaten by the larvae of butterflies, put netting over one area of the crop and leave the other area exposed for butterflies. The netting, available at most garden centres, will prevent the female from laying her eggs on the plants.
Butterflies thrive best in a sheltered garden, and you can plant tall shrubs, vines or trees around the perimeter to provide a windbreak. Try to select plants that will provide shelter as well as nectar: pink or white viburnum bushes to line the perimeter; a wall or trellis of yellow or white honeysuckle, or purple wisteria; plant cherry, chestnut, pear or plum trees along the perimeter.
Additional shelter for overwintering butterflies in your garden can be provided by a log pile at least 3 to 5 feet high and 3 to 6 feet long (Figure 2). A suggested alternative to the log pile is the use of a butterfly hibernation house which can be purchased at many garden and nature stores. While this has been suggested to be attractive to butterflies, recent reports state that none have been seen using them. One of the most credible statements about butterfly box use is found on the “Frequently Asked Questions” page of the National American Butterfly Association web site [http://www.naba. org/qanda.html], where the NABA is asked if butterfly boxes work, and answer "Unfortunately, no. While so-called butterfly boxes can be attractive, and do little harm, studies have shown that butterflies do not use them in any way." View an article about this at http://www.suite101.com/article.cfm/butterfly_gardening/16477, and another at http://butterflywebsite.com/articles/showarticle.cfm?ID=27. But if you want to build a butterfly house and try it for yourself, building plans are available at http://butterflywebsite.com/articles/house/plans.htm.
|Figure 2. Butterfly log pile.1|
As butterflies and hummingbirds frequent your flowers the use of pesticide is highly discouraged. Therefore, if you prefer to have perfect flowers and are a heavy pesticide user, I would recommend trying not to attract hummingbirds and butterflies. There are many natural and low-toxicity pesticides available and I would suggest using those but only during the leaf stage of the plant. Once the plant is in flower and the hummingbirds and butterflies are visiting, I would discontinue pesticide usage.