Monarch Populations are Declining, but Planting Milkweed Can Bring Them Back. It’s important to choose the right milkweed variety.
We have an update for this post, originally published in 2019 when the Monarch butterfly populations were at an all time low. We have been are growing milkweed in our garden for the past two years and we have never seen so many butterflies. We just heard that the Monarch butterfly population in the Monterey Bay area has increased this year. Maybe the number of people growing milkweed in their garden is helping.
We live in Santa Cruz, California, one of the areas where the Monarch butterflies gather after their migration. We regularly see Monarchs in our garden. Their populations have been declining drastically. Scientists have said that planting milkweed would help, since Monarchs require milkweed for their life cycle. They lay their eggs on the milkweed and the young feed on the toxic plant, making the caterpillars undesirable to birds other prey. Planting milkweed also provides flowers for bees and other butterflies as well. So we added some milkweed to the garden this year.
This proved to be a little bit harder than just going to the local nursery, picking out a variety of milkweed that we thought was pretty, and then planting it. The monarchs that travel in different parts of the country require different varieties of milkweed. Planting the wrong kind may actually be detrimental because it may overwinter and harbor pathogens that could harm the right kind of milkweed. Below, is a photo of the milkweed we had last year that was the wrong kind. It still attracts butterflies and provides food for the adult butterflies, and occasionally we saw a butterfly laying an egg on it, but we rarely saw caterpillars on it.
With the help of the Monarch Joint Venture website, we were able to determine which varieties of milkweed the Monarchs in our area preferred. We searched online (using the Latin names for the milkweed varieties, to make sure we had the right ones) and were able to find seed for two of the preferred varieties for our area, Oscar and Showy.
We had total failure on the seeds started indoors. The plants started in planters outside, however, quickly germinated. The Monarch butterflies had no trouble at all finding them and we now have small Showy Milkweed plants covered with Monarch eggs and caterpillars.
A second generation of Monarch butterflies returned to lay eggs on the milkweed we planted for them. We are hoping we have established a place they will return to each year. They are attracted to the milkweed flowers as well as for a place to lay eggs.
The milkweed attracted butterflies constantly, all summer long. There was rarely a time when there was not a Monarch in the garden. It was also a favorite of other butterflies, bees and hummingbirds. The Oscar variety, Asclepias physocarp, from Johnney’s Selected Seed Company, grew extremely well and the plants were covered with caterpillars all summer. It also produced lovely white orchid-like flowers and large ornamental seed pods that looked like balloons. It made an attractive garden plant as well as being helpful for the Monarchs. The other variety, Showy, from a different company, grew poorly, but was the obvious favorite of the butterflies, so we will try it again next year.
Photos by Tony Fitzgerald Photography