Joe Pye weeds have thick stems with lance-shaped, serrated dark green leaves that can be up to a foot long. And in the midsummer, tiny mauve or pink-purple flowers bloom in large clusters atop the stems. Although it’s often considered just a roadside week, Joe Pye weed has a sweet vanilla scent that is especially attractive to butterflies and other pollinators, and it has become an increasingly popular plant for native gardens. Joe Pye weed is best planted from potted nursery plants in the spring after the threat of frost has passed. It has a fast growth rate, usually flowering in its first season. Staking and timely pruning may also be necessary to keep these towering plants on their best behavior.
Light
Joe Pye weed grows best in full sun to partial shade. Too much shade can encourage legginess and cause the plant to flop over. Shady conditions also can make the plant susceptible to disease. However, Joe Pye weed also appreciates some protection from the hot afternoon sun, especially in the summer months. Too much strong sun can cause yellowing of the leaves.
Soil
This wildflower is adaptable to many different soil conditions, but it will do best in fairly rich, well-drained soil. The plant is tolerant of clay soil and wet soil, and mature plants even have some tolerance for short periods of drought. It is notable as a plant that tolerates nearly all soil pH levels.
Water
Maintaining consistent soil moisture is key for growing a robust Joe Pye weed. During your plant’s first growing season, keep the soil evenly moist at all times but not soggy. Even after the plant is mature, try not to let the soil remain dry for more than a few days at a time, especially during hot weather. A layer of mulch around your plant will help to retain soil moisture and keep the roots cool.
Temperature and Humidity
Joe Pye weed is fairly hardy both to cold and to heat within the climates of its growing zones. Frost will cause the plant to begin dying back to the ground for the winter. Humidity (or lack thereof) typically isn’t an issue, as long as the soil remains moist.
Fertilizer
If you are growing Joe Pye weed in its native fertile environment, you generally won’t need to feed it at all. But if you have poor soil, apply a slow-release granule fertilizer formulated for flowering plants in the spring as soon as active new growth begins. Fertilize again in the midsummer when blooms begin to appear. It also can be beneficial to mix compost into the soil around your plant in the spring.
Types of Joe Pye Weed
The various species of Joe Pye Weed are extremely similar in appearance, and the ones offered at local garden centers often are simply sold as “Joe Pye Weed” (Eutrochium) without any further species distinction. But serious gardeners might be interested in the species details:
Eutrochium purpureum: This species is native across the central and eastern U.S., zones 4 to 9. It has solid green stems with purple leaf nodes, and grows to 7 feet in height. Clusters of tiny mauve flowers appear in mid to late summer.Eutrochium maculatum: This variety has purple-speckled stems with light to dark purple flowers. It is hardy in zones 4 to 9. There are several named cultivars within this species, usually bred for resistance to powdery mildew. Eutrochium dubium: This species sometimes has purple stems and features dark purple blooms. The east coast native grows to about 5 1/2 feet tall. The flowers are an attractive pink-purple.Eutrochium fistulosum: Green stems with muted pink-purple flowers adorn this species. Another eastern U.S. native, this species has whitish flowers and prolific seed heads that birds love to feed on.Eutrochium steelei: This species has greenish-purple stems and pink or purple flowers. The native of the Appalachian mountains has greenish-purple stems and grows to 6 1/2 feet.
Pruning
Once cold weather arrives in the late fall, Joe Pye weed goes dormant and dies back. You can either prune the dead foliage to about 4 to 8 inches above the ground at this time or wait until early spring to do this garden cleanup. The plant blooms on the new season’s growth, so don’t wait until it’s too late in the spring to prune, or it can be difficult to prune around the new growth. If you wish, you can limit the overall size of your Joe Pye weed by cutting the stems back by half in June. This will cause the plant to send out more stems and encourage shorter, bushier growth. Consequently, you’ll get even more flowers on those new stems.
Propagating Joe Pye Weed
Division of roots is the easiest way to propagate mature Joe Pye weed plants. It is best done in early spring as soon all danger of frost has passed, but propagation in the fall is usually successful, too. Few plants are easier to propagate.
How to Grow Joe Pye Weed From Seed
Joe Pye weed is not easy to grow from seeds, because the seeds require a period of cold stratification in order to germinate. Purchased seeds or those saved from a spent flower head can be stored in the refrigerator for at least a month before planting. If starting indoors, start the seeds about eight weeks before the expected last frost. Or, they can be planted outdoors in spring.Fill starter cells or 2-inch pots with moistened seed starter mix. Press the seeds into the soil and just barely cover them with additional mix. Place the container in a location with bright indirect light at 70 degrees Fahrenheit until they sprout, usually about 4 weeks. Continue to grow the seedlings in a bright location until outdoor planting time.
Overwintering
These wildflowers require no special winter protection, but it’s a good idea to cut the stalks back to just above ground level when frost kills the plants, or after the flowers have faded. Doing this work in the fall will simplify your spring cleanup chores.
Common Plant Diseases
By far the most common problem for Joe Pye Weed is powdery mildew, Although it is rarely fatal, powdery mildew’s dusty covering of the leaves can hinder their ability to photosynthesize, sometimes causing the leaves to dry up and die. Powdery mildew sometimes responds to fungicide sprays or powders, but you can reduce its appearance by avoiding overhead watering and giving the plants plenty of space for air circulation. Better yet, choose one of the named cultivars, which are generally bred for their resistance to mildew:
E. dubium ‘Baby Joe’E. dubium ‘Little Joe’E. fistulosum ‘Carin’E, fistulosum ‘Bartered Bride’E. maculatum ‘Phantom’E. maculatum ‘Purple Bush’
How to Get Joe Pye Weed to Bloom
It’s rare for gardeners to have trouble getting Joe Pye weed to bloom, but the plants sometimes underperform if they don’t get enough sun or if they experience extended drought conditions. And very poor soil can sometimes hinder the blooms. But generally speaking, Joe Pye weed will bloom if it gets enough light, enough water, and just a small amount of nutrition.
Common Problems With Joe Pye Weed
Like many native wildflowers, Joe Pye weed is renowned for its easy-care attitude. Problems are rare and usually easy to solve:
Leaves Are Scorched
Mature plants can handle short droughts, but too much dry soil for too long will cause Joe Pye weed to shrivel and scorch. Make sure the plant is getting enough moisture in the heat of summer.
Powdery White Residue Covers the Leaves
This is the notorious powdery mildew (see above). Treat the plant with spray fungicide; prevent the problem by planting mildew-resistant varieties.
Orange Spots on the Leaves
Though not nearly as common as powdery mildew, rust fungus can also leave brownish-orange spots on the leaves of Joe Pye weed. It’s rarely a serious problem, but if the disfigurement bothers you, try treating the plant with a spray fungicide.
Wind Topples the Plants
Too much feeding or not enough sunlight can cause these plants to get leggy and topple over from the wind. Keep feeding at a minimum and make sure the plants receive adequate light, which will keep them from reaching for the sun. Cutting back the stalks by half in early summer can keep the height under control and prompt the plant to become bushy rather than excessively tall. Staking is another option.F
