Milkweed Week. . . Can Milkweed plants exhibit Albinism?

Hello friends! We hope you all had a wonderful and safe holiday weekend!

This week, we are featuring Milkweeds! We treasure our Milkweeds in the park because they are essential for Monarch butterflies. Monarch butterflies can only lay their eggs on milkweed plants because that is the only thing Monarch caterpillars will eat. Picky eaters are the worst, am I right? Monarch caterpillars and my childhood-self have something in common, haha!

In all seriousness, Milkweed is closely tied to the Monarch’s survival. Milkweeds get their name from the toxic, milky latex in their leaves. The Monarch caterpillar eats milkweed leaves and absorbs the toxins from the latex. It stores these toxins in its body and becomes poisonous and inedible for predators. The caterpillar maintains its toxicity even once it metamorphoses into a butterfly! Predators that eat Monarchs will not die, but they will become very sick indeed!

Photo credits: Sonia Altizer, courtesy of Science magazine and Monarch photo courtesy of

CVNP is home to five different species of milkweed. If you go looking for milkweed this week, you will most likely find Common milkweed, or Asclepias syriaca. Common milkweed can bloom between June and August. It has broad, light green leaves with a purplish-pink bloom. Common milkweed can be found in meadows, but it prefers disturbed areas, such as roadsides and cropland:

Photo credits: Alan Cressler, John Hixson, and W.D. Bransford & Dolphia, all courtesy of Lady Bird Johnson Center

Here are the other four species of milkweed you might see in CVNP this week:

Poke milkweed (Asclepias exaltata):

Poke milkweed can bloom between mid-May and mid-July. It has dark green leaves with a purplish-white and green flower. Poke milkweed is often found in gaps of deciduous forests.

Photo credits: Alan Cressler and R.W. Smith, courtesy of the Lady Bird Johnson Center

Swamp milkweed (Asclepias incarnata):

You’ll see Swamp milkweed’s white, pink, or pinkish-purple bloom anywhere between July and August. As the name suggests, Swamp milkweed does well in swamps and wet meadows.

Photo credits: Stephanie Brundage, courtesy of the Lady Bird Johnson Center and Jennifer Anderson

Fourleaf milkweed (Asclepias quadrifolia):

Fourleaf milkweed tends to bloom between May and July. It has a pale pink bloom and is often much shorter than other milkweed species. Fourleaf milkweed prefers dry, open woodland habitat.

Photo credits: Jim Stasz, and W.L. Wagner

Whorled milkweed (Asclepias verticillata):

Whorled milkweed dons its white bloom between June and September. Whorled milkweed can be found in sunny grasslands and disturbed areas. It has needle-like leaves and is one of the most toxic milkweeds. In fact, this milkweed is considered a noxious weed for farmers because it has been known to kill livestock.

Photo credits: R.W. Smith and Carolyn Fannon, courtesy of the Lady Bird Johnson Center

BONUS FACT: Did you know that Milkweeds can exhibit ALBINISM?

Animals exhibit albinism by lacking melanin, a common hair, skin, and eye pigment. Plants can exhibit albinism by lacking chlorophyll, the green pigment that allows them to photosynthesize. Some milkweeds, like Common milkweed, sprout new plants via their root systems. Albino milkweed, then, survives by absorbing nutrients through its root systems with the parent plant. This can be classified as a form of parasitism.

One of our iNaturalist project members, Christine Krol, discovered TWO albino Common milkweeds in CVNP! She has documented photo observations of the plants throughout the growth season; their progress is very exciting:

Photo Credits: Christine Krol

I know that was a long feature, but milkweed plants sure are cool! Have a great week, everyone!

Posted by mklein1216 mklein1216, July 06, 2020 14:47


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