From the Garden: Milkweeds for Monarchs!

By Erin McKenna Breglia, Landis Gardener

Monarch on Butterfly Weed

Many peo­ple enjoy see­ing but­ter­flies in our Lan­dis gar­dens. espe­cial­ly the monarch but­ter­fly, Danaus plex­ip­pus. Besides hav­ing a beau­ti­ful appear­ance, the monarch has an impor­tant eco­log­i­cal role. It serves as a pol­li­na­tor for food crops as it migrates across the North Amer­i­can con­ti­nent. While the monarch can serve as a food source for birds, spi­ders, and ants, the lar­vae feed exclu­sive­ly on milk­weed and con­sume pro­tec­tive car­diac gly­co­sides, mak­ing them unpalatable.

The monarch migrates each spring from the south­west­ern Unit­ed States and Mex­i­co, trav­el­ing to the Amer­i­can Mid­west and as far north as Cana­da. These but­ter­flies typ­i­cal­ly arrive at Lan­dis by mid-sum­mer and migrate back south­west­er­ly in Sep­tem­ber to com­plete their life-cycle. While at Lan­dis, the Monarch but­ter­fly feasts on nec­tar from our abun­dant offer­ings includ­ing Eupa­to­ri­um mac­u­la­tum (Joe Pye weed), Sol­ida­go sp. (gold­en­rod), Echi­nacea sp.(coneflowers), Dau­cus caro­ta (wild car­rot), Cir­si­um sp. (this­tles), and Ascle­pias spp. (milk­weeds).

Though the monarch but­ter­fly will enjoy an array of flower nec­tars, its lar­vae or cater­pil­lar stage feed exclu­sive­ly on milk­weed. At Lan­dis, we have three vari­eties of milk­weeds grow­ing: Ascle­pias syr­i­a­ca (com­mon milk­weed), Ascle­pias incar­na­ta (swamp milk­weed), and Ascle­pias tuberosa (but­ter­fly weed). Strate­gi­cal­ly plant­ed near one anoth­er, these plants begin to bloom in sum­mer and con­tin­ue through August. If dead­head­ed, the plants may con­tin­ue to flower into autumn. 

Com­mon milk­weed spreads by seed and rhi­zome, the plant’s under­ground run­ner-like roots. It is a great plant choice to fill large vacant spaces, espe­cial­ly with oth­er strong-willed native plants like aster, sol­ida­go and wild car­rot. While it can run wild in a tame gar­den bed, it can be some­what con­trolled by remov­ing the seed pods before they open. Much of the plant is actu­al­ly an edi­ble veg­etable when pre­pared cor­rect­ly. I have eat­en the spring shoots sauteed with but­ter and gar­lic, and the pods when har­vest­ed young and bat­ter fried can be com­pared to a mild fried okra. 

The swamp milk­weed and but­ter­fly weed at Lan­dis are the last plants to emerge, com­ing up from the ground in June. We have learned through expe­ri­ence that it is impor­tant to keep these plants marked to be sure they are not mis­tak­en for weeds. The but­ter­fly weed has gor­geous orange flow­ers, while our swamp milk­weeds are cream col­ored. They gen­er­al­ly bloom at the same time and con­tin­ue to bloom for up to two months, espe­cial­ly if munched on by some hun­gry monarch caterpillars. 

Unfor­tu­nate­ly, pop­u­la­tions of mon­archs have dra­mat­i­cal­ly declined due to cli­mate change, log­ging, pes­ti­cide use, and habi­tat loss. Though not fed­er­al­ly endan­gered in the U.S, they are list­ed as a species of spe­cial con­cern in Ontario, Cana­da. As recent aware­ness high­lights the decline of impor­tant pol­li­na­tor species across the North Amer­i­can con­ti­nent, it is easy to see that grow­ing a vari­ety of milk­weeds is a sure way to encour­age monarch but­ter­flies to stop by and enjoy our gar­dens. To know they call Lan­dis home, even if only for a short vis­it dur­ing their thou­sands-of-mile migra­tions, ignites a child­like won­der and adult appre­ci­a­tion year after year.


Summer 2022

Volume 40 , Number 2

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