- Author: Karen Metz
I started growing milkweed a few years ago when I heard about declining numbers of Monarch butterflies. I planted Narrow-leaf Milkweed or Asclepias fasicularis, a California native. This plant is a perennial that dies back every winter but comes back in spring. Its flowers are small cream-colored and to be honest, pretty lackluster. On the plus side, it tolerates clay soil. Like many milkweed species, they seem to be a magnet for aphids. Interestingly the plants never seem particularly bothered by them. Over a year or two, the plants got more robust looking but I never saw a Monarch adult or caterpillar. I decided perhaps if I added another species of Asclepias nearby, that might attract the Monarchs.
So, the next thing I planted was Asclepias curassavica or Tropical Milkweed. It has broader leaves and much more attractive flowers. These are clusters of orange and red blossoms. It is not native to California but still has the aphid problem that Narrow Leaf Milkweed has. Still no Monarchs. Then this year saw a real drop in Monarchs sightings, down to zero for many sites. But a few weeks ago, Kathy Keatley Garvey wrote in her blog, Bug Squad, that there had been two different sightings in Vacaville. I vowed to start watching my plants with vigilance. They are in my side yard in my backyard, not that easy to get to. But I was also headed down that way each day to pick up the ripe pineapple guava which falls to the ground and needs to be picked up.
So, I was definitely paying more attention to my milkweed than I ever have before. I was still amazed at the number of aphids. I saw ladybug larva show up as well to feed on the aphids. Then one day I rounded the corner and saw a milkweed pod on the Narrow Leaf Milkweed. It had just split and the little seeds with their silken parachutes were spilling out ready to be taken off by the wind. Okay, it wasn't a Monarch, but it was really beautiful. And if I hadn't been on lookout duty for the Monarchs, I would never have seen it. By the next day, the pod and the seeds were gone.
Now just an addendum about Asclepias curassavica or Tropical Milkweed. This has turned out to be a controversial plant. Apparently, Monarchs can pick up a parasite called Ophryocystis elektroscirrha or OE for short. When they visit this plant, the parasite can survive on the plant. In its native location, it's not a big problem as the plant dies back. But now it's being grown in other locations where it's not dying back and large levels of the parasite are building up in some plants. Some groups say if you severely cut back the plant in late fall that will take care of the problem. Other groups suggest not growing the plant at all. As for me, since I have never seen any Monarchs near either kind of Milkweed I grow, I think I will just cut my Tropical Milkweed back in November.