Asclepias incarnata. Photo courtesy of Rich Baer

Mike Darcy
Head “plant nerd,” longtime speaker, host of gardening shows on radio and TV, and author of the In the Garden email newsletter.
You can reach Mike, or subscribe to his newsletter, at [email protected].

Strange as it may seem, plants and clothes have some traits that make them parallel to one another.

Clothes are fashionable. New styles appear every year, but there are always some holdovers from previous years. A parallel can be drawn here with plants. Some become more fashionable in gardens, while others fade away.

Hellebores and clematis are good examples. I can remember when both were not elevated to the prominent positions that they hold in gardens today. At the same time, there are some plants with staying power; they have maintained a stable position for many years. Roses and peonies are two that come to mind.   

A current trend in garden centers is pollinator plants. I have seen garden centers with special sections labeled as such. Generally, these sections feature plants that are attractive to butterflies, but honeybees and other native bees also would fall into this category.

Technically, almost any plant can be considered to be a pollinator if it has pollen and or nectar and is attractive to bees and butterflies. However, there are certain groups of plants that are promoted as pollinators. They seem able to attract more pollinators than others.

Fit for a king or queen

The plant genus Asclepias, commonly known as milkweeds, has been one of the most prominent in garden center pollinator sections. It’s a best seller among pollinator plants, noted especially for attracting butterflies.

Of all the butterflies we have, the monarch has been in the news in the past few years and has garnered much attention from the public. As the name suggests, this butterfly is considered the king of butterflies.

Asclepius physocarpa. Photo courtesy of Rich Baer

The population decline of the monarch is probably due to more than one reason, but certainly a primary cause is the decline of the milkweed plant which it needs in order to reproduce. Milkweed plants are the sole host plant for monarch butterflies.

Many milkweed species can also be a host for the monarch caterpillar, although the crawling larvae prefer some varieties over others. In years past, many farmers would leave a perimeter around their fields for native plants to grow and provide shelter and food for a variety of wildlife.

Today, in many cases, this practice has been eliminated and crops are often planted to the edge of the fields. With no food source, wildlife populations diminish. This is where the home gardener enters the picture by making pollinator-friendly gardens with a diverse variety of plants.

What’s native in Oregon?

There are some species of Asclepias that are native to Oregon. These easily can be incorporated into a native garden. The native plant section at a garden center is another emerging fashionable trend. Having some native Asclepias is like a double bonus: a native plant and a butterfly attractant.

Species of milkweed that are native to Oregon include:

• Asclepias cordifolia (purple milkweed, heart-leaf milkweed),

• Asclepias cryptoceras ssp. davisii (Davis’ milkweed),

• Asclepias fascicularis (narrow-
leaved milkweed), and

• Asclepias speciosa (showy milkweed)

It is interesting to note that the monarch butterfly uses these plants as both a nectar source and as a host plant to lay eggs on.

Probably the most popular Asclepias for home gardeners is A. speciosa because it is a well-known monarch attractor and the plant looks quite nice in a garden bed. The plant can be treated as an herbaceous perennial and it is winter hardy. It will die to the ground in the fall but should reappear in the spring.

In my own garden last year, I planted Asclepias incarnata (swamp milkweed). It is not an Oregon native — rather, it is native to Missouri — but it performed very well in my garden with attractive pink flowers. It is a clump-forming plant and grows in areas with poor drainage. While I did not see any monarch butterflies, it did attract our native swallowtail.

Another native Asclepias from Missouri is A. tuberosa (butterfly weed), which has often been used as a bedding plant. It is noted for the clusters of bright orange flowers and is often referred to as butterfly weed. In 2017, it was named Perennial Plant of the Year by the Perennial Plant Association. What was once called Asclepias physocarpa has had a name change to Gomphocarpus physocarpus. Whichever name you call it, it is a show stopper in the garden. It goes by the common name of balloon plant, hairy balls, or sometimes family jewels tree. It is the seed pods that draw attention to this plant because they are inflated, lime green pods up to three inches across.

My friend Rich Baer grew this in his garden and it reached a height of over eight feet in one season. The stems of the seed pods make a spectacular bouquet that will definitely draw attention. This plant is also a monarch pollinator.

Asclepias incarnata.
Photo courtesy of Rich Baer

Not just about butterflies

In garden centers, a pollinator display does not have to be just about butterflies. Our native Ribes sanguineum (flowering currant) is an excellent pollinator plant, as is Solidago (aka goldenrod). Other plants to include would be Ceanothus (California lilac), lavender and annuals such as alyssum, zinnias and asters. There are many others that could also be included.

To highlight this area, I would recommend having a notation that these plants are perfect for a pollinator garden. Also, highlight the name Asclepias because right now these are hot plants and garden centers can hardly keep them in stock.

Now is the time to get ready and take advantage of this trend while the buzz words abound. The monarchs are waiting — and so are the gardeners.