Monarch Migration
Texas enjoys a unique privilege every September through mid- November as the largest migration of monarch butterflies passes through the state, bound for select over-wintering sites in the Michoacan state of Mexico. Considered one of the most fascinating of animal migrations, estimates of 100 million to 400 million monarchs concentrated within two prominent flyways ‘waltz’ across Texas.
The central flyway is approximately 200 miles wide, traversing the center of the state from Wichita Falls to Eagle Pass. Moving along the Texas Gulf Coast, the coastal flyway migration occurs later in October through mid-November. It is thought that the monarch population of the central flyway comes primarily from the mid-western prairie states, while monarchs east of the Mississippi generally use the coastal route. These southbound fliers can cover distances up to 2,980 miles in three months, with an average distance of 80 miles a day. Riding thermal air currents and the prevailing wind, they can fly at altitudes up to 3,280 feet, expending little energy.
Butterfly rest stops
Along their amazing journey, the monarchs must frequently rest and feed to replenish their energy. Migrating monarch butterflies are seeking the carbohydrates and other chemicals derived from flower nectar. Many fall-blooming native and adapted plants are excellent landscape choices for refueling monarchs.
Generally the best butterfly nectar plants are found in the Aster, Mint, Madder and Vervain plant families. Fall aster (Aster spp.), goldenrod (Solidago spp.), verbena (Verbena spp.), and Gregg’s mistflower (Conoclinium greggii) are reliable perennial plant selections attractive to monarchs. Frostweed (Verbesina virginica), a native fall-blooming perennial, is a butterfly favorite. Mexican bush sage (Salvia leucantha) seems to be the monarch’s sage of choice. Mexican milkweed (Asclepias curassavica) is a strong enticement to both migrating monarchs and hummingbirds. This tender perennial or reseeding annual is an important host plant species that will benefit the monarch butterflies as they migrate south, as some will be breeding even in the fall, and again as they begin their journey north in spring.
For annual color in the garden, choose from butterfly favorites like pentas (Pentas lanceolata), lantana, (Lantana spp.) zinnia (Zinnia elegans, Z. linearis), and Mexican sunflower (Tithonia rotundifolia). The aptly named butterfly bush (Buddleia davidii), a hardy semi-evergreen shrub, produces white, pink, lavender, purple or yellow flowers from early summer through fall.
Extended stay
Visiting monarchs will remain in an area rich in nectar plants until a cold front advances and moves them along towards their winter mountaintop homes in the oyamel fir (Abies religiosa) trees of Mexico. Your garden may host hundreds or even thousands of monarchs for a few days while they shelter communally in a nearby tree.
It is one of nature’s richest rewards and most memorable of experiences when the migrating monarchs, the official state insect of Texas, come to call at your garden.
About the author: Tina Dombrowski Tina Dombrowski is the Director of Horticulture at Texas Discovery Gardens at Fair Park, Dallas. She has a particular interest in Texas native plants, butterflies, pollinating insects and their interconnected histories.
Learn more about it:
Monarch Watch, www.monarchwatch.org
North American Butterfly Association, www.NABA.org
Texas Discovery Gardens, www.texasdiscoverygardens.org
Texas Monarch Watch, Texas Parks & Wildlife,
www.tpwd.state.tx.us/huntwild
For Tina’s complete story, see the September/October issue of Neil Sperry’s GARDENS Magazine. Click here to subscribe or order back issues.