WESTCHESTER COUNTY, N.Y. -- Our youngest generation may be the last to ever see a beautiful Monarch butterfly. Since the 1990s the Monarch population has dropped by more than 90 percent from an estimated one billion Monarchs to only 33 million today.
There are a number of reasons why the Monarch population is crashing – deforestation of their overwintering sites in Mexico and California, radical changes in farming practices, widespread pesticide use, and the disappearance of milkweeds.
Butterfly caterpillars have a different diet than their adult counterparts. Most caterpillars eat plant parts, usually leaves. Monarch caterpillars have evolved to eat only the leaves of milkweeds (Asclepias species) which are their “larval host plants.”
While we often plant nectar-producing plants in our landscapes to feed adult butterflies, we rarely plant the larval host plants that their caterpillars must have. This absence of host plants in our landscapes, in combination with our frequent use of pesticides, has contributed to reduce the populations of many butterfly species – including the highly threatened Monarch.
This fall, you can help save the Monarch butterfly in your own landscape in two ways: 1) plant regionally native milkweeds and 2) keep your landscape pesticide-free.
In spite of their unfortunate common name, milkweeds are beautiful and wonderful additions to every yard. Not only do milkweeds feed Monarch caterpillars with their leaves, they support countless pollinators and other beneficial insects with their nectar.
Here are some native milkweeds to consider planting this fall:
Swamp Milkweed (Asclepias incarnata)
Full to part sun 2 – 4 feet high Pink blooms in summer
Butterflyweed (Asclepias tuberosa)
Full sun;welll drained soil 1-3 feet high Orange blooms in summer
Purple Milkweed (Asclepias purpurascens)
Full to part sun; dry to moist soil 2 – 4 feet high Rose pink blooms in summer
Whorled Milkweed (Asclepias verticillata)
Full sun to part sun; dry to moist soil 1 – 2 feet high White, light green blooms in summer
Tall Milkweed (Asclepias exaltata) Part shade to part sun; average to moist soil 2 – 5 feet high White, light green blooms in late spring to early summer
White Milkweed (Asclepias variegata)
Full to part sun; average to moist soil 1-3 feet high White blooms in early summer
Common Milkweed (Asclepias syriaca)
Full to part sun; average to dry soil 2-6 feet high Pink blooms in summer
Common Milkweed is a critical plant for Monarchs but has a spreading root system and should be sited accordingly. It is a wonderful choice for natural areas and a terrific replacement for tough invasive plants in sunny spots.
For more in-depth information on milkweeds: http://www.ecobeneficial.com/2014/07/closer-look-monarchs-milkweeds-latest-information-xerces/
Look for milkweeds at your local nursery and also join me at the Native Plant Appreciation Weekend at Rosedale Nurseries in Hawthorne on Sept. 6-7. Volunteers from The Native Plant Center will be on hand to help you shop for lots of great native plants – including milkweeds!
Kim Eierman, a resident of Bronxville, is an environmental horticulturist and Founder of EcoBeneficial! When she is not speaking, writing, or consulting about ecological landscapes, she teaches at the New York Botanical Garden, Brooklyn Botanic Garden, The Native Plant Center and Rutgers Home Gardeners School.