There’s a spot along the Piedras Pintadas trail at Lake Hodges where Indian Milkweed (Asclepias eriocarpa) grows – they generally seem to prefer the higher altitudes and there’s plenty of them in the Laguna Mountains and at Palomar Mountain, but “down here” in the coastal inland areas, this is the only place where I’ve found them. It’s also known as Woollypod Milkweed, or Kotolo (see Etymology section, below).
Milkweeds in general get their name from the white sap that is released when cells are damaged, ie. when a part of the plant (leaf etc.) breaks off. All milkweeds are toxic and A. eriocarpa is actually on the higher end of toxicity: when livestock like sheep ingest only 0.05 to 0.25% of their body weight in A. eriocarpa plant material, they may die.
Monarch butterfly caterpillars primarily feed on milkweeds. The butterflies collect the Milkweed toxins in their bodies, and when birds eat the butterflies, they get poisoned — so they learned to avoid the Monarchs, which protects the butterflies during their migration. Fascinating nature stuff!
I knew where this beautiful perennial plant would be growing and where to look from previous years, but I didn’t expect it to be growing so slow. I made the first photos of the plants that already had flower buds at the end of April, and expected that it wouldn’t take much longer for the flowers to fully mature — but it took another three weeks until the buds finally opened to reveal the flowers, and release their wonderful scent. It was worth the wait and the frequent returns to this trail!
The common name “Woollypod Milkweed” is slightly misleading — it’s certainly not just the seedpods that are woolly, it’s pretty much the entire plant! Interestingly, I found that the plants down here in Rancho Bernardo appear to be more hairy than their siblings in the higher regions. Similarly, the leaves seem to curl up on their margins a lot more down here than up in the mountains.
With currently 17 photos, this is a rather large gallery — I guess you can tell that this is one of my favorite plants around here!
Some of the photos from this gallery are available in my store: Milkweed prints (opens in a new tab). Should you be interested in another photo that is not available in the store, please simply contact me and I’ll add it for you.
Looking for the origin of the genus name Asclepias, one can find slightly contradicting, but nevertheless complementary information: Carl von Linné described milkweeds first in 1753, and supposedly derived the name Asclepias from the Greek god of medicine and healing, Asclepius — apparently because the plants have a long history of being used in traditional medicine. On the other hand, according to Wiktionary, Asclepias comes from the Latin adaptation of the Greek word for “swallow-wort” — but this also hints at the medicinal use.
The epithet eriocarpa is composed of the Greek “erion” (ἔριον) for wool and “carpa” for the fruit, which is reflected in the common name “Woollypod Milkweed” — I’m not sure if “pod” refers to the actual fruit (seedpod) or perhaps the closed flowers before the petals open…