Lincoln Conservation Organizations’ Wall Lettuce Project

Name: Anna Wilkins  Organization: Lincoln Conservation Organizations  Phone: 781-259-9251

Site location:
lat: 42°26'7.04"N Long: 71°18'12.59"W Pipeline trail off of Bedford Road.

Basic property description:

This area is part of the Flint's Pond conservation area which is overall mixed hardwood forest.

Management area description:

Hemlock grove (heavily affected by wooly adelgid), northwest slope, adjacent to gas pipeline right-of-way.

Acres in the management area: 6.37  Listed on EDDMaps? No

Habitat type: Hemlock forest, Right-of-way, Upland/wetland edge

Was this Early Detection Rapid Response (EDRR)? Yes

Initial Overall Invasive Distribution Description:

Wall lettuce was found throughout the 6 acres. Overall average distribution was about 40% over the total area with heavily infested patches throughout.

Initial Overall Percent Cover of Invasives: 26 - 50%

Target species:

Management objectives:

We wanted to contain the infestation from spreading throughout the rest of the Flint's Pond property and adjacent private lands. We were also hoping to get the infestation reduced to a manageable size so that it might be controlled with a slight amount of annual maintenance.

Approximate project start date: June 1, 2013

Years this project has been ongoing:

Project summary:

This six acre wall lettuce infestation site has been worked on for four years via pulling. We discovered infestations of wall lettuce in a few locations throughout town and were alarmed at the size and location of this patch because it was along a right-of-way and was also penetrating into interior forest acres of conservation land. This site is on a fairly steep slope and the terrain is tricky due to fallen hemlock trees and branches. We were limited to mechanical means of control due to staffing and wetlands.

The area seems to staying within the original boundaries with large amounts of hand pulling efforts throughout the growing season, but the percent cover is about the same as the initial area. Though there are areas where a decrease in plant population can be seen.

Control method: Manual

Disposal method: Left on site

Detailed project timeline:

Hand pulling begins in June when the plants begin to bolt because at this stage (just before flowering) they are easier to pull. If they start to go to flower, sometimes we'll weed whack to keep them from going to seed and buy ourselves more time to pull. But weed whacking promotes multi-stem re-growth so it is imperative that we return to pull the plants before the second growth goes to seed.

Pulling can be done all year, however, once it goes to seed, pulling will cause the airborne seeds to disperse and potentially can cause more harm than good.

Even if an area has been intensively pulled and at the time it appears that you have pulled every visible plant (important to get the perennial roots), we found one needs to return at least twice before the hard frost to get the escapees or re-growth from remaining roots. Flowers have been seen into late October.

In this area we are also testing smothering areas with black plastic. We put plastic down two years ago. We plan to pull it up in the summer of 2017 to see if the seed bank is extinguished.

Funding sources: We used staff time in our annual budgets for the work and supplies.

Final acres in management: 6.37

Open to the public: Yes

Able to Provide Tours: Yes

Success Rate:

Current Overall Percent Cover of Invasives:

Comments / Takeaways

On the sites where we get every plants, we see good results after two or three years. But this site, due to it's size and difficult terrain, is very difficult to get every plant and we're seeing much slower progress. Multiple trips throughout the season are definitely a must. We should also mention we found some areas we had disturbed with garlic mustard pulling were areas that were then hit hard by wall lettuce.

Last Updated: June 6, 2013