weed taking over 3 acres of wooded/shrub area
This weed is taking over our property. It started at the front near the street one year and 3 years later it has reached the back yard and is even eradicating the English ivy in the back. (ok English ivy is not ideal however at least it's a ground covering.). It doesn't have a fuzzy underside of leaf. I've tried mowing it everywhere I can and hand pulling it where I can't. It has taken over our property. What can we do about this weed?
The main weed we see is the non-native (foreign) invasive grass known as stiltgrass.
Stiltgrass spreads like wildfire and has taken over hundreds-thousands of acres of natural and park lands, not to mention private land. Nothing eats it or infects it enough to kill it.
It is an annual. In the lawn, mow it to keep down seed production someewhat. Pull it is beds.
A crabgrass pre-emergent herbicide can be used in the spring to prevent seed germination, but it must be applied more than once over the growing season for full control.
Here is our webpage about controlling it: https://extension.umd.edu/hgic/topics/japanese-stiltgrass
We're not sure what is planned for the areas in your photos, whether this is lawn or not. At any rate, stiltgrass will be producing its seeds at the end of August or in September. Keep an eye out for the seed heads. Be sure to cut it down or pull it before it produces more seeds that will come up next year.
And, we hope your English ivy is not climbing trees. As you know, it is a terrible invasive plant and when it climbs trees it produces berries which the birds spread into parks and natural areas.
We have a little over 2 acres of mostly trees and azaleas. No formal lawn, just a small area in the back near a small fish pond that I mow. 10,000 daffodils in the spring. We have well water and we don't water anything in the yard except a few plants, bushes and trees close to the house. We don't use pesticides or herbicides on our property.
We tried the mow and hand pull method rather aggressively last year trying to control these weeds however the problem is even worse this year. And hand pulling weeds for 2 acres is a bit difficult. Pre-emergent for all 2 acres seems difficult too.
Is there nothing else I can do?
Because Japanese stiltgrass is an annual weed, preventing seed dispersal is a key to its management. Seeds of Japanese stiltgrass can persist in the soil at least 5 years and the seeds will germinate when light/moisture conditions are favorable. You most likely have an established seed bank in your soil and will continue to see new stiltgrass plants emerge because of this.
Established plants will eventually die at the end of the season, but you will have to either pull or cut flowers before the plants produce and disperse seeds. Japanese stiltgrass begins to produce flowers in August. We encourage physical methods of removal to the extent possible before resorting to chemical controls -- especially over a large area. Mowing, string trimming, pulling, mulching are all options you can do to try to prevent seed dispersal. These plants are extremely difficult to control and there are no easy solutions.
Rutgers University has more comprehensive information on control options in landscape beds and lawns. https://njaes.rutgers.edu/fs1237/