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Joe Pye Weed – Native Plant of the Week

Here’s the final installment of our weekly summer highlight of native plants. Thanks to our intern Amalia for her passion on this important topic! -Erica, Horticulture Educator

If you’ve ever seen hazy-pink flowers on a tall stem beside a North Country road or stream around this time of year, chances are that it was Joe Pye weed or a close relative. While often thought of as a wetland plant, several species are highly heat and drought tolerant, making them suitable for a variety of landscapes. Joe Pye weeds are scientifically known as the genus Eutrochium, which consists of five species, all native to North America. Its often-confused sister genus, Eupatorium, by contrast, encompasses hundreds of species across multiple continents. Let’s explore the distinction between these two genera, and what makes Joe Pye weed special! 

First some history: Once upon a time, all these plants were lumped together under the genus Eupatorium, and commonly as the bonesets, thoroughworts, snakeroots, and more. Most of these plants have white flowers and leaves that occur in opposite pairs, while the Joe Pye weeds have pink or purplish blooms and grow whorls of three to six leaves along their stems. 

The name Joe Pye weed is thought to come from a prominent Mohican leader, Joseph Shauquethqueat, often referenced in historical documentation with the surname Pye, who lived in colonial-era New England. He, or others using the name ‘Joe Pye’ (with various spellings) have sometimes been attributed with using the plant in question to treat typhoid fever and other ailments, though there is very little specific evidence for this. 

In the early 19th century, the eccentric but instrumental French-American naturalist Constantine Samuel Rafinesque was the first to propose separating Joe Pye weeds, scientifically speaking, from other members of Eupatorium, and gave them the name Eutrochium. This did not catch on, however, and in 1970, research botanists Robert M. King and Harold Robinson, unaware of Rafinesque’s proposal, suggested the same grouping change but gave their new genus the name Eupatoriadelphus. That name was then widely accepted and started gaining popular usage. In 1987, though, King and Robinson acknowledged their Eupatoriadelphus to be the same group that Rafinesque had described, but nonetheless decided to regroup them under Eupatorium. Following further research published in 1999 and 2004, including DNA analysis, the Joe Pye weeds were once again split off from Eupatorium, and the small genus finally became formally known as Eutrochium. 

To keep things muddled, some nurseries and informational sources continue to use any of the three genus names to refer to Joe Pye weed, as well as perpetuating confusion between a few of its species. You may therefore still find Joe Pye weed advertised or discussed with the name Eupatorium or Eupatoriadelphus; just be aware that Eutrochium is the most current and accurate name for it. 

Four of the five Eutrochium species are popular landscape plants throughout North America and Western Europe. The exception is E. steelei or Steele’s Joe Pye weed, which grows almost exclusively in the Southern Appalachian region at a specific elevation. 

Coastal plain Joe Pye weed, E. dubium, also has a fairly narrow native range along the eastern U.S. coast, but has become widely popular as a landscape plant due to its relatively smaller size (typically less than 5 feet tall), very good heat and drought tolerance, and moderate salt resistance. 

Pink flowers, like others featured but more compact
Eutrochium dubium (photograph by David J. Stang, distributed under a CC BY-SA 4.0 license)

Eutrochium dubium and the other three species not yet mentioned are all native to various parts of New York State, but only two are present in St. Lawrence County – Eutrochium maculatum or spotted Joe Pye weed, and Eutrochium purpureum or purple Joe Pye weed. The other is E. fistulosum, with common names trumpetweed or hollow Joe Pye weed. In the wild, E. fistulosum is a generalist wetland plant, and can grow to a gigantic 6 to 10 feet in height. In a garden setting, though, it will typically stay a more manageable size, and is very heat and drought tolerant. It’s native to a few counties scattered across New York State, but is not recorded as present here in St. Lawrence County. Read more Joe Pye Weed – Native Plant of the Week

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Goldenrod – Native plant of the week

Goldenrods, or members of the genus Solidago, are a truly essential part of our native landscapes, and suffer from some common misconceptions. This week, we’ll look at why goldenrod is so important, clear up those myths, and check out some common species you can cultivate – to help native pollinators, and for your own enjoyment! 

First of all, about that pesky myth: that goldenrod pollen causes allergies.  

In fact, the plant primarily responsible for those seasonal allergies, sometimes called hay fever,  is ragweed. Ragweed is pollinated by wind rather than insects, so it has tiny inconspicuous flowers that produce copious amounts of extremely fine pollen, which then drifts through the air in hopes of landing on other ragweed flowers – irritating the respiratory systems of unfortunate humans along the way. Goldenrod, on the other hand, is pollinated by insects, so it produces heavy, sticky pollen to attract and nourish them. The insects pick up some of the pollen when they visit to eat it or drink the flower’s nectar, and then transport it to the next flower they stop at – hopefully another goldenrod plant. This pollen never becomes airborne (unless perhaps you bump into or shake the plant, in which case some might fall to the ground), and therefore does not cause allergies. 

Ragweed on the left, compared to goldenrod on the right
Ragweed is on the left, and goldenrod is on the right.

How did this get mixed up? While the two plants look very little alike, it probably stems from the fact that they bloom around the same time. Since people don’t notice the flowers of ragweed, they probably see the shaggy, bright yellow (pollen-colored) blooms of goldenrod, and assume that it must be the source of their suffering – then spread this mistaken assumption around. This unfortunately discourages some people from cultivating goldenrod.  

Goldenrod is an extremely valuable plant to pollinators and other insects. It is a keystone species in many North American ecosystems – meaning so many other species depend on it that if it was removed the entire system would change drastically. In goldenrod’s case, this is mostly because so many things like to eat it: around 130 species of lepidopterans (butterflies and moths) use it to host their larvae, just in our area! Plants in the Solidago genus are the only host for many of those species. These butterflies and moths are not only pretty, and important pollinators themselves, but both larvae and adults are also crucial food sources for many species of birds, especially for parents trying to feed their young. 

A few of the species that solely rely on goldenrod are the Asteroid Moth or Goldenrod Hooded Owlet (Cucullia asteroides), the Diamond Spot Pearl or Beet Webworm (Loxostege sticticalis), the Bilobed Dichomeris Moth (Dichomeris bilobella), and the Confused Eusarca (Eusarca confusaria).

Three beige moths
Top left: Eusarca confusaria (photograph by Andy Reago & Chrissy McClarren, distributed under a CC BY 2.0 license). Bottom left: Loxostege sticticalis (photograph by Marcello Consolo, distributed under a CC BY-NC-SA 2.0 license). Right: Cucullia asteroides (photograph by Andy Reago & Chrissy McClarren, distributed under a CC BY 2.0 license).

Aside from hosting the larvae of so many insects, one of the most important roles goldenrod plays is providing abundant nectar and pollen to feed pollinators in the late summer and fall. When many other flowers are slowing down and ending their blooming season, goldenrod fills in as a primary food source for these insects and other animals. This is especially crucial to migratory butterflies like Monarchs, which rely on this plentiful, easy-to-find nectar during their flight south in the fall.  Read more Goldenrod – Native plant of the week

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Phlox – Native Plant of the Week

Many people have strong feelings about phlox. Some love its beautiful blossoms and others are frustrated by the deer browsing and its spreading nature. Regardless of which side you lean towards, there are good reasons why it’s a popular garden plant, and since some species are native to the North Country, let’s take a closer look at a few of those! 

First though, a bit about the genus: Phlox is a group of perennial flowering plants, most of which are native to North America. They are frequently cultivated by humans for their showy and often fragrant flowers, and with many different species to choose from and countless varieties and cultivars, it can be extremely versatile in a garden. In fact, the genus name Phlox comes from a Greek word meaning flame, in reference to the vibrant flowers of some varieties. Phlox flowers are a tubular shape which divides into five petals – although you may occasionally find a four- or six-petaled blossom in a cluster. The flowers often have a color difference in the center around the opening, which serves as a guide for pollinators seeking nectar. 

Two examples of phlox flowers with concentrated pigments toward the flower centers.
Note the concentrated pigments at the centers of the flowers.

Let’s start with a true-blue wild native – Phlox divaricata, which goes by common names including timber or wood phlox, wild sweet william (not to be confused with Dianthus barbatus, which is also called sweet william), and wild blue phlox. Its native range covers the central and eastern United States and eastern Canada, growing wild in forest floor environments, where it may grow in clumps or spread more horizontally, reaching 6 to 12 inches high. In gardens it prefers partial to full shade, and moist well-drained soil that is high in organic material, to approximate its natural growing conditions. P. divaricata blooms in the spring, starting as early as April. The wild type is typically a light blueish purple color and has narrower, more separated petals than most phloxes, but cultivated varieties and cultivars can range from bright violet pink to blue and sometimes white, and flower shape may be similar to other domestic species. 

blue cheerful flowers growing wild by a rock
Phlox divaricata, or wild blue phlox.

Next, Phlox subulata, which is known commonly as moss phlox, creeping phlox, thrift, and more rarely, moss or ground pink. Interestingly, “pink” is a name which this phlox shares with some members of the Dianthus genus, from which we get the word for the color pink. P. subulata is also native to central and eastern Canada and the U.S., and is most prevalent in the Appalachian Mountains. It has a very different growth habit than some of the other species, with trailing stems spreading from a single base to form a dense mat of foliage – about six inches high and two to three feet wide. Stems become woody with age, and foliage becomes sparser in the center of the plant as new growth continues around its outer edges. If you want to maintain density at the center, the stems can be cut back to about half their length when the plant is done flowering. P. subulata can be grown in sandy or gravelly soil, as it often does in the wild, and it is more tolerant of hot or dry conditions than most other species of phlox. It grows in a variety of colors, is spring flowering like P. divaricata, and has a bit smaller flowers than the other two species (about ¾ inch wide).

Low, dense pink flowers and vegetation
Phlox subulata, or moss phlox.

The last species we’ll look at is garden phlox – Phlox paniculata. Some other common names for it include autumn or fall phlox, summer phlox, and tall phlox, and you can likely guess a few of its features from that list of names. It does indeed bloom from midsummer into fall, and grows taller than most other species, about two to four feet. Here in the pollinator garden at the Extension Learning Farm, our P. paniculata has just started blooming, and past years’ records show it will be mostly done by mid-August, but may trickle into late September.  Read more Phlox – Native Plant of the Week