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harvesting joe pye weed seeds

Although the flower heads seem fairly dry, they still need to be dried a few days by spreading them out on a tarp. Once dry, the seeds must be cleaned before using. It is fairly easy to clean the seeds. Just put the flower heads on top of a piece of fairly course screening (available from a hardware store) and scrape them back and forth. The seeds fall through, and the empty stems can be thrown away. Store the seeds in a dry place in a grocery bag until time to plant.

Yesterday I spent an hour or so collecting woodland Joe Pye weed ( Eupatorium purpureum ). This species is relatively similar to the wetland Joe Pye weed ( E. maculatum ), but less colorful and better adapted to woodland areas. It is a strikingly tall species that has become established in those parts of our savannas which have more closed canopy (50% or even a bit more).

The best stands of E. purpureum are north of our North Fire Break, just before the steep drop off into the oak woodland. I used the Kawasaki Mule to get in there, and it was an enjoyable day, quiet and peaceful. I got two buckets full of seed heads.

While I was seed collecting, I was also keeping my eye out for small buckthorn that needed spritzing or basal barking. Fortunately, the buckthorns were fairly scattered here, and I proably only treated a couple dozen plants. I carried a spray bottle in my belt pack. We’ll be back in this area in the winter for more extensive buckthorn work. Hopefully, this will be a low snow year so that we can get some work done!

Seed: Joe-Pye seed heads can be collected in late September. Cut a seed head, place it upside down in a large, brown paper bag, and hang the bag in a well-ventilated room for the seeds to finish maturing and drop into the bag. The seeds can be planted directly in the soil during the fall, or they can be stored in a sealed bag or jar in the refrigerator until sown. If planted in the fall, young plants will appear in the spring. Keep seedbed moist for both germination and growth of seedlings, which will flower the second season.

The ultimate height of these cultivars is directly influenced by the amount of sunlight received, how consistent the soil moisture is, and the degree of soil fertility. For example, in a trial study ‘Baby Joe’ Joe-Pye weed grew to 5 feet tall, but nursery descriptions of this cultivar’s height are often listed as 3 – 5 feet, 3 – 4 feet, or as low as 2 – 3 feet tall. The same is true for the other cultivars. However, if a Joe-Pye weed species or cultivar grows too large for a specific landscape plan, the stems can be cut halfway down by mid-June. The plant will then re-sprout and be shorter, but more full and with more flower heads.

Joe-Pye weeds need a soil that is consistently moist the first year for establishment and that contains at least some organic matter. They can tolerate more drought in subsequent years, but do thrive in drainage ditches that are more moist than the typical surrounding soils. Joe-Pye weeds are generally tall plants and most effectively are planted toward the rear of landscape gardens. They combine well with ironweed (Vernonia fasciculata), which is also equally tall and with dark purple flowers; goldenrods (Solidago spp.), with golden yellow blooms; and native asters (Aster novae-angliae and A. laevis), with lavender petals and yellow centers.

Propagation

Joe-Pye weeds (Eutrochium spp.) are early fall blooming wildflowers that colonize roadside ditches in sunny, moist sites. These native perennial plants grow to 4 – 6 feet tall and bloom along with goldenrods (Solidago spp.), ironweeds (Veronica fasciculata), and our native grasses to make a beautiful autumn display. The flowers are mildly fragrant and very attractive to butterflies and other beneficial insects.

Joey Williamson, PhD, HGIC Horticulture Extension Agent, Clemson University

If this document didn’t answer your questions, please contact HGIC at [email protected] or 1-888-656-9988.

Division: Mature plants are best divided in the fall after they go dormant. Each plant will have numerous stems arising from a wide crown with a fibrous root system. To divide the crown, place a sharp shovel between the stems and force it downward to cut, and then separate pieces of stems along with their portion of the crown and roots. Replant the separated piece at the same depth as it was originally, and then mulch and water to settle the soil.

For the majority of remaining seeds, I use clear cups for collection. I like clear cups because I can see how many seeds I’ve collected, spot the occasional insect that needs rescue, and I can label the cups with a marker to keep things organized.

Joe Pye Weed’s seeds are mature when the large purple flowerheads have begun fading and turning to brown. Hundreds of seeds are attached to white tufts which will carry them away in the wind. Place a paper bag over a seed head and shake the flower stalk to free the seeds.

Storing Seeds

Tomato seeds are coated with a fleshy growth deterrent that you’ll need to remove before drying. Some people use a fermentation process to remove this fleshy coating, but I prefer to soak the seeds in water with 10% hydrogen peroxide for a few hours. After a few rinses of fresh water, I dry and store the seeds as normal. This method is used for any seeds encased in pulp or flesh.

Clusters of immature green seeds with a few mature seeds in back

Joe Pye Seed Heads almost ready to harvest