One of the many pleasures of gardening is watching the butterflies that visit our flowers. Like so many other wild things, our local butterflies appear to be in trouble. The number and variety of species that I see dwindles each year. There has been a noticeable shift from larger species, such as the fritillaries, to smaller, more nondescript one, such as skippers. This shift may reflect the shift in vegetative cover in this area from deciduous woods to open fields, and the loss of habitat to development.
report revealed that the population of monarch butterflies (Danaus plexippus) has crashed in the last decade. Mexican scientists report that wintering populations that previously covered 50 acres of trees this season covered only 3 acres. Several possible reasons for this sharp decline, all related to human activity, have been proposed.
One explanation for the serious decline in the numbers of this beautiful butterfly may lie in the severe summer heat and drought that has been experienced in the central and southern states in recent years. The unusual weather patterns may result from climate change.
Another possible factor is the loss of habitat in Mexico, where the butterflies spend the winter, due to logging.
A third possibility is the widespread use of GMO crops, specifically "Roundup Ready" soybeans in the United States. The genetically engineered soybeans are unaffected by the herbicide, glyphosate, making it possible for farmers to almost completely eliminate milkweed from their fields. Milkweed is the food plant for the monarch's caterpillar. Adult monarchs feed on a variety of nectar plants, but the caterpillars will only survive on milkweeds.
Tennessee has 13 species of milkweeds, including butterfly weed (Asclepias tuberosa), swamp milkweed (A. incarnata) and common milkweed (A. syriaca). These three are often available in garden centers that carry native plants. Several of our other species have showy flowers and could be valuable garden plants, also. Milkweed seeds germinate readily and the plants are easy to care for, in my experience. Many have a pleasant fragrance, as well.
For a small donation, you can receive milkweed seeds appropriate for planting in your garden from this web site, LiveMonarch.comhttp://www.livemonarch.com/free-milkweed-seeds.htm
Our local garden centers, including Stanley's Greenhouses, Ellenburg's Nursery, and Mayo Garden Centers, all offer Asclepias plants among their perennials flowers. You can also often find a tropical species, A. curassavica, which won't overwinter here but will charm you with its fiery red and yellow blooms.
Milkweed seed pods are among the most familiar sites along our back roads in late summer and early fall. You can harvest a few seeds from wild plants and grow them out at home. Wait until the pod has split and seeds are being released to collect them. Sow immediately outdoors, marking the spot well, and look for seedlings the following April or May. Transplant them to their permanent location, water well, and wait. They will bloom in their second or third season, depending upon the species and growing conditions.
Appropriate growing conditions for milkweeds depend on the species. Swamp milkweed, as you might guess, likes moist places. I see the flowers shining among other types of foliage in roadside ditches that hold water. Butterflyweed, on the other hand, likes dry, sharply drained sites. I have seen beautiful specimens growing out of crushed limestone fill on roadside embankments. Common milkweed seems to prefer average moisture and soil conditions, no doubt accounting for its widespread distribution.
This spring, why not add a few milkweed plants to your garden to help feed the monarchs?