Monarch butterflies are in trouble.
Studies in the Mexican forests where the butterfly spends winters show a sharp decline in population, especially over the last three years. This year, the butterfly covered only 1.65 acres of woodlands compared with 2.94 acres last year, according to Monarch Watch. The species covered almost 51.81 acres at its peak in 1996.
There are many reasons for the troubling statistics, including habitat destruction in Mexico and severe weather conditions that have affected the butterfly’s favorite plants. Genetically modified crops, which can resist the herbicide Roundup, have also been an issue. Spraying does not affect GMOs but it kills weeds such as milkweed, which is the butterfly’s host plant.
In spring, Monarchs make a spectacular migration from Mexico to North America and return in the fall. On both journeys, they need host plants and nectar plants to feed on.
Advice for gardeners is simple: Plant milkweed everywhere. There are four major types:
Tropical milkweed (Asclepias curassavica) — Grown as an annual here, it’s planted toward the end of May and succumbs to frost at the end of the season. The tender leaves make a great food source for the larvae and the flowers provide nectar for the adults.
Swamp milkweed (A. incarnata) — a perennial plant that will come back each year. It does like wet soil but will also grow in average garden soil despite its name. The pink blooms are beautiful and fragrant, too.
Common milkweed (A. syriaca) — Also perennial, it spreads through underground runners and will thrive in full sun and average to poor soil. The flowers are purplish with a sweet aroma.
Butterfly weed (A. tuberosa) is shorter than the other two perennials with deep orange flowers that appear in summer.
There are also other plants which help the monarch at the end of the summer to get ready for the migration south.
Showy goldenrod (Solidago speciosa) is beautiful, clump-forming (and) extraordinarily polite. It has beautiful majestic strong spikes of yellow and it’s super late-blooming.
Liatris, also known as blazing star, blooms in July and August. Any of the cultivars will work, but meadow (Liatris ligulistylis), prairie (L. pycnostachya) and rough blazing star (L. aspera).
Asters that attract the butterfly include sky blue (Aster oolentangiensis), New York (Symphyotrichum novi-belgii) and white (S. ericoides). New England aster (S. novae-angliae).
■ The Audubon Center for Native Plants and Audubon Nature Store at Beechwood Farms Nature Reserve are at 614 Dorseyville Road, Fox Chapel (15238). Information: (412)-963-6100 or www.aswp.org. They sell four different types of milkweed and have a very limited supply of free seeds for common milkweed. They are also holding a “Marvelous Milkweed” native plant workshop July 11, 1-3pm at Beechwood Farms and July 12, 2-4pm at Succop Nature Park.
Monarch Watch is a great web site devoted to saving the butterfly.
The Million Pollinator Garden Challenge asks gardeners to create pollinator gardens and register them. It’s fun, easy and important.