Henry Homeyer: Flowers fit for garden royalty

By Henry Homeyer
©2021 Telegraph Publishing LLC

Monarchs are on the move! It is time for their long trip to Mexico to spend the winter. And like marathon runners, they need to bulk up on calories before the event. You may have let a patch of milkweed grow on the edges of your property to support them.

That is great, and many of us have done that. But the milkweed plants are for the caterpillars to munch on. Right now, they offer nothing to monarchs. Our monarchs need blooming flowers for nectar and pollen.

Of the monarchs I see floating around my gardens, three plants seem most attractive to them for feeding right now: Joe Pye weed, goldenrods and asters. Let’s look at these and their garden worthiness.

Joe Pye weed (Eupatoreum maculatum) is a native wildflower that likes stream edges and places with good moisture, though it will grow almost anywhere it is planted. It is a big plant, often 5 or 6 feet tall in the wild. It is a clumping plant, with the clumps getting bigger every year.

It is readily found in plant nurseries, although most sold are a named cultivar, one called “Gateway.” I have found that Gateway blooms longer and does better in a vase than the truly wild ones that have popped up along my stream. There is now a smaller Joe Pye that is called “Little Joe,” that only gets to be three to four feet tall. It is a patented variety that does not breed true, and is actually a different species in the same genus, Eupatorium dubium. Then there is one called “Baby Joe,” but I have not yet tried either one.

The flowers of Joe Pye weed are a light purple and appear in large panicles at the top of the plant. The stems of Gateway are a deep purple, though the wild ones tend to be greener. Plant Joe Pye weed where you want it as the fibrous roots go deep into the soil, and when firmly established they are nearly impossible to dig out.

Goldenrods are a wonderful, though frequently maligned genus of plants. For many years they were prohibited in arrangements in the flower room at our county fair, as it was believed they caused hay fever. They do not. They have a heavy, sticky pollen that does not fly in the air but is transported by insects. There are at least 20 species of native goldenrods including some that prefer shade, while others demand full sun.

Goldenrods are important not only for monarch butterflies, but also for many butterflies, moths, bees and other pollinators. And yes, some of the big, sun-loving species will expand their territory and send tenacious roots deep into the soil, even muscling out some dainty perennials.

Years ago I purchased some blue-stemmed goldenrod (Solidago caesia) at The Garden in the Woods in Framingham, Massachusetts. I grow it in both dry shade and in rich soil in moist shade. It has never been a pest, or traveled around my garden beds, staying just where I planted it, blooming in September and into October. It is quite dainty.

My favorite goldenrod is a variety called “Fireworks,” of the species Solidago rugosa. It prefers full sun and moist soil, but I have also grown it in part sun and fairly dry soil. Its flowers are tiny, blooming first at the tips and working their way down the 3- to 4-foot stems. The stems arch gracefully like a fireworks display. They can be divided every 3 to 4 years to keep the clumps to a manageable size, and to increase (or share) them.

All the asters and aster-family flowers are great for monarchs and other butterflies. Scientists don’t call the genus aster any more, but Symphyotrichum, which is a shame as it is much less user-friendly.

There are at least 30 species of asters that grow wild in America, including many nice shade-loving ones that are certainly uprooted as weeds by tidy gardeners long before they bloom now, in the fall.

Asters have flowers with many rays and a bright yellow eye. They range from deep purple to white, along with pink and a light blue. All are quite tough, surviving any winter thrown at them.

Similar to asters, and a plant I just saw visited by a hungry monarch, is New York ironweed (Vernonia noveborancensis). It has smaller, deep purple blossoms in big clusters at the top of stems that can reach 9-feet tall.

According to Tracy DiSabato Aust in her fabulous book, The Well-Tended Perennial Garden, shorter, later-blooming plants can be created by cutting back all the stems to the ground when they reach 2-feet tall. I shall certainly try that next spring. I moved mine from moist soil to dry soil in part shade partly because it got too tall in the full sun.

If you care about your monarchs, plant native plants. Native plants are much more useful to pollinators and wild animals than plants imported from other continents. Many of the native plants are just as beautiful and pleasing to me in the garden, and hopefully they are to you, too.