When I am out driving around Adams County, the tall purple flowers I see along the roads and in the fields always catch my eye. Those bright purple flowers are ironweed. Ironweed begins blooming in late July and is most noticeable during August and September. This perennial plant is easy to spot as it can grow anywhere from 3 to 8 feet tall. Once this plant is in bloom, it is very easily recognizable. The flowers are a vibrant purple color and arrange as a wide, flat panicle of flowers with anywhere from 10 to 30 small, fluffy florets.

Ironweed is a native flower that attracts many pollinators as it is a late season source of nectar for multiple species of insects and butterflies. One native bee that is particularly fond of ironweed is the Denticulate Long-Horned Bee. This bee is a solitary bee that flies during the fall, meaning it relies heavily on the presence of ironweed. For those wanting to incorporate more late blooming native crops into your landscape, gardens, or other areas, ironweed is an option. A few different species of ironweed are found in Ohio. The most common species is giant ironweed (Vernonia gigantea), which is the one described. New York ironweed (V. noveboracensis), Missouri ironweed (V. missurica)) and prairie ironweed (V. fasciculata) which is a shorter variety that has more densely compacted flower heads, are also found throughout Ohio.

Ironweed grows well in full sun to light shade. Ironweed favors moist conditions, which makes it a good option for planting near stream banks, a wetter site, or in a rain garden. Ironweed grows in clumps as it has short thick rhizomes and fibrous root systems. This perennial spreads easily by its many seeds and can quickly fill in a space. Ironweed is considered an easy plant to grow. Due to the ease of growth, weather resilience, and tiny flower seeds, ironweed can easily take over an area. To help reduce it from spreading, do not allow the flowers to go to seed as they are quickly spread by wind. With its bitter flavor, wildlife tends to leave ironweed alone.

Be cautioned that ironweed is considered a nuisance weed in grazing pastures and is often controlled as livestock will not eat it due to the bitterness. This leads to undesirable populations of ironweed. Like most management systems, multiple controls are suggested to help reduce the population of ironweed. Mowing or clipping ironweed will prevent seed formation and remove top growth, which can help allow grasses to grow more vigorously. However, mowing alone will not reduce the presence of ironweed in your grazing pastures. Herbicides are often needed as part of the control for ironweed.

Herbicide control should start in early July by mowing emerged ironweed stems. When plants regrow to 10-20 inches in height, apply a pasture herbicide containing triclopyr (eg. PastureGard, Crossbow, etc.) or aminopyralid (eg. GrazonNext, etc.) as a broadcast treatment. This approach is only necessary for moderate to heavy ironweed populations. If you have a lighter population, spot treatment of individual pants will help keep populations from becoming a major problem. Emerged clovers within the treated areas of the field are likely to be killed. Consult the herbicide label of the product used for minimum reseeding intervals for clovers and other desirable forage grasses.

Upcoming Events:

• Junior Fair Beef BBQ- September 7 at the Ohio Valley Career and Technical Center from 4:30 – 7 p.m. Tickets can be purchased in advance at the Extension Office or purchased the day of the event.

• Farm Science Review- September 19 – 21 at the Molly Caren Agricultural Center in London, Ohio. Tickets can be purchased in advance at the Extension office for $10. Tickets may also be purchased at the gate for $15. Children 5 and under are free for this event.