I have contacted four different parks systems in my area to get information on their restrictions regarding plant removal and their use of herbicides, and the only one who has gotten back to me has been Ralph White of the James river parks system.
I wanted to let you all know what he said so you can be safe out there and choose your foraging spots judiciously. So, here is What Mr white told me in our email conversation:
"The park does use herbicides. The predominant chemical is glyphosate (Round Up), but other more persistent types are also used. In either case, the impact is the same for you: collecting of plants is strictly forbidden. You may not forage in the JRPS.
To note have such a regulation would open the park to the kind of wholesale plant theft that we had when the park first opened. It has take us decades to re-introduce species. You may eat berries and fruit and nuts while you are in the park, but not collect bags full to take out. And obviously you may not dig up any plants whatsoever. There is a rather stiff fine for doing so: $250."
I then followed up, asking where exactly he used the herbicide and whether it was safe, in his opinion to eat pawpaws off the trees. This was his response:
"We have been using a small amount of Round-Up to control poison ivy along our trails. On Belle Isle, I used some to address vegetation growing in the Prison Cemetery area; I don't think we got around to doing the trail edges yet. This herbicide was used near and along the stonework of the main canal feature at Pump House Park and along some of the trails near the parking lot at Pony Pasture Rapids Park.
This herbicide photo-degrades 50% in the first 24 hours and has no easily detectable residue after 5 days. It is labeled as being safe for pet and human contact after 20 minutes, ie, when it has dried.
We use very little herbicide in the JRPS and that which we do use is considered to be the least impactful. We do occasionally use a very small amount of more persistent chemicals under the guardrails and fence posts along Riverside Drive. For both time and money reasons, we did not do so this year.
I think it is safe to eat Pawpaws collected along the shoreline and islands of the JRPS."
In speaking about this issue with other foragers around the country, I have heard it mentioned that a blue dye is often added to herbicide, and therefore the absence of blue coloring means it's safe to collect there. I have never personally seen this, even after I have seen workers out spraying, but I do find it a generally good rule of thumb to avoid any areas where plants look unwell. Along the roads near my house, they have sprayed this year with something that has killed everything and turned all the plants an orangish brown dead color. Why they think that looks better than the weeds is beyond me. Anyway, the safest course of action is always to harvest in places where you have permission from the land owner and are aware of their practices.
If I receive a response from Chesterfield county, city of Richmond, or the state parks systems, I will update you on those also.