A charming perennial herb with the capacity to grow to a decent height, Eutrochium maculatum is a lovely plant for any ornamental garden. Synonymous with Eupatoriadelphus maculatus, it is commonly known as Joe Pye weed, spotted trumpet, and queen of the meadow. This plant is a member of the large Asteraceae or sunflower family, of which Eutrochium is just one of almost 2,000 genera. It is native throughout North America and is the only species of its genus that is found in some western regions of the US.
Often mistaken for its close cousins, E. purpureum and E. fistulosum, this species is distinguished by its spotted stems. The spots, which may look like tiny lines or speckles, are purple or green. The stems tend to have varied densities of hair, just as the leaves do. Notably serrated and tapered on both ends, the leaves occur in whorls at intervals along the central stem. Though they may measure around 7 inches (18 cm) long, they are borne on markedly short petioles. The terminal flower heads, which are light pink to purple, consist of about 8 – 20 disk florets each. These arise in summer and can last for as long as 3 – 4 weeks.
Facts, Benefits & Uses of Joe Pye Weed
Species classified under the Eutrochium genus are often irresistible to butterflies, and this spotted wildflower is no exception. It is also a host plant to the larvae of several moth species, including the eupatorium borer moth (Carmenta bassiformis), three-lined flower moth (Schinia trifascia), Clymene moth (Haploa clymene), and the ruby tiger moth (Phragmatobia fuliginosa). Honeybees are also known for gathering nectar from the fragrant, petalless blooms.
Several cultivars of this species are recipients of the RHS Award of Garden Merit. These include ‘Orchard Dene’, ‘Riesenschirm’, and ‘Purple Bush’. As Joe Pye weed has a preference for moist to wet soil, it can be planted along the edges of water features or in a rain garden. It naturally occurs in marshes, swamps, and fens, but can also thrive in man-made areas that tend to accumulate seepage. Compared to other wetland species, it is unfortunately not highly resistant to floods.
As with most plants that favor wet areas, this species’ root system is largely fibrous and tends to spread outward, producing colonies that arise from its rhizomes. Fortunately, it is not known for being invasive or weed-like. In part, this is likely due to its preference for natural rather than disturbed areas. In the wild, it usually grows alongside shrubs or small trees that have a similar preference for moist substrates.
Joe Pye Weed Growth, Hardiness & Climate
E. maculatum thrives best in fertile soil with a rich concentration of minerals. It can tolerate being planted in slightly calcareous zones as long as the substrate is regularly moistened. Its appeal in rain gardens is largely due to its ever-changing features, making it a plant for year-round interest. Even when its leaves have mostly browned or fallen in winter, its dried seed heads continue to persist.
This species can be grown as a border plant or meadow plant with multiple colonies in areas that receive full to partial sun. It can tolerate slightly alkaline to slightly acidic soil and is usually hardy to seasonal fluctuations in temperature, particularly in USDA zones 4 – 8.
More light exposure and mild temperatures are, of course, preferable as these facilitate the production of dense inflorescences. The floral heads can be heavy enough to weigh down the stems, causing them to arch over adjacent plants. At the peak bloom period, each inflorescence can become as wide as 7 – 12 inches (18 – 30 cm)! They truly become a feast for pollinators.
How to Plant Joe Pye Weed
Joe Pye weed can be planted using its seeds or root divisions. Propagation via seed can be much more challenging, though it is more likely to generate several plants as a reward for the effort. For ideal germination rates, seeds need to be cold-stratified before they are sown onto a sterilized potting mix. Distribute them over the surface of the substrate. You may lightly press them into the soil, just to secure their position, or barely cover them with a very fine layer of substrate.
Regularly mist the soil to prevent the surface from drying out. You may place a lightly perforated plastic sheet above the setup to delay evaporation rates. The seeds should be exposed to sunlight and temperatures that average at around 70˚F (21˚C). If light conditions are adequate, they should produce their first true leaves in as little as 4 weeks. Once the seedlings are large enough to handle, they can be transplanted into their own individual pots or into the garden. Leave about 12 inches (30 cm) of space between each one. To minimize damage, out-planting should be done in spring.
Root division is more straightforward due to the plant’s tendency to produce rhizomes. It is also a surefire way of obtaining exact copies of the mother plant. However, this can only be done for plants that have already generated stemmed offsets. To divide the roots of the offsets and the mother plant, push a sharp shovel into the soil space between the stems. Dig out the root ball of the offset, taking care to cleanly separate it from that of the mother plant. Replant the offset in another moist location, taking care to keep the soil at the same depth.
How to Care for Joe Pye Weed
With proper care, your Joe Pye weed should begin producing flowers in its very first season. It may have a relatively fast growth rate, particularly if the soil is regularly moistened and enriched. Regularly and deeply water the soil around the plant, especially if it is located in a brightly sunlit area. Watering may need to be done more often through summer to prevent the soil from drying out. Leaves are likely to wither and fall due to dry soil. If they turn yellow, it is possible that the soil lacks moisture or nutrients.
Stands of Joe Pye weed will rarely have serious pest problems due to their antimicrobial properties, but do monitor the foliage for signs of infestation. If orange spots or powdery residue appear on the leaves, you may need to treat the plant with an organic fungicide. Manually remove any pests when they are sighted, but note that insect larvae may generally favor the leaves as a form of sustenance. Browsing by wild animals will rarely compromise the survival of this species.
How to Winter Joe Pye Weed
In areas with markedly cool winters, Joe Pye weed naturally dies back once temperatures begin to drop. If you’re interested in leaving the stems in place, despite the withered leaves, you can leave the plant be through winter. Simply mulch the soil around the dormant roots to keep them protected from significant temperature fluctuations.
Some horticulturists opt to prune the shoots before the year ends, in spite of the fluffy seeds that provide winter interest. It may be harder to neatly prune the old shoots once new growths have appeared. If pruning the shoots in the fall, cut them down to about 4 – 8 inches (10 – 20 cm) above ground level. Pruning the plant even before its shoots have died back should encourage a bushier and more floriferous habit.
Is Joe Pye Weed Invasive or Toxic?
Although E. maculatum has the tendency to spread quite vigorously to form clonal colonies, it is not considered an invasive species. This is due, in part, to its sensitivity to soil conditions and reliance on pollinators to produce viable seeds. Despite its capacity to seed freely, seed dispersal rarely leads to its prolific spread. However, you may have difficulty controlling the localized spread of this species if your garden soil is generally rich and moist all throughout.
Joe Pye weed is not considered a toxic species, though it does contain some compounds that may harm the liver if ingested in high quantities. These are present in the form of pyrrolizidine alkaloids. Note that a few close relatives of E. maculatum are considerably more dangerous. For example, E. rugosum (white snakeroot) has been implicated in the death of cattle.
Is Joe Pye Weed Edible? Do Animals Eat it?
E. maculatum is considered an edible herb when consumed in small doses. An infusion made with the entire herb is associated with medicinal benefits that can supposedly aid in the treatment of urinary disorders, neuralgia, dropsy, fever, and more.
Some insects and wild animals readily feed on the foliage and seeds of Joe Pye weed. Swamp sparrows may occasionally benefit from the seeds. The leaves are not always a favorable choice for herbivores, though they may browse on the plant when better food sources are unavailable.
Where to Buy Joe Pye Weed & Seeds? (UK & US)
Eupatorium maculatum can be purchased from garden centers and plant nurseries throughout its native range. It is normally available as young plants or as seeds. Online plant portals that cater to international orders should be able to serve you if you are outside of the US. Some plant nurseries in the UK also supply a variety of Joe Pye weed cultivars. Make sure to review your locality’s requirements for obtaining non-native plants if you wish to purchase this species online.
