Sunday, June 14, 2015

In This Cornahh -Garlic Mustahhd!

The fight against garlic mustard, Alliaria petiolata, will be a long one. Above, you see a partially cleared area to the east of the drainage stream and an uncleared zone to the west (right side). Below you see the waterway and woods we are trying to protect.

Jewelweed, Impatiens capensis, is a native inhabitant of this part of the woods but comes to rise late as it is quite frost intolerant. It's also a lovely plant in leaf, flower, and remedy. I love this part of the woods and do not want to see it over run, but that's what's in store without our management. Sadly, we'll have to create some compaction damage in order to pull garlic mustard. With that in mind, keen observation is drumming up some techniques that keep us pulling only once a year until the seed bank is exhausted. This area has now been completely cleared (but not of buckthorn, another day).

In all, we cleared about 1 acre of garlic mustard. That's a drop in the bucket, but we had to start somewhere. Above, you see it gaining a foothold among our rare wild-growing ferns. Garlic mustard is a biennial that outcompetes everything around it by growing before winter loses its grip. It also leaves chemical compounds that help establish its foothold.

From Wikipedia:
"Garlic Mustard produces allelochemicals, mainly in the form of the cyanide compounds allyl isothiocyanate and benzyl isothiocyanate,[16] which suppress mycorrhizal fungi that most plants, including native forest trees, require for optimum growth.[17] However, allelochemicals produced by Garlic Mustard do not affect mycorrhizal fungi from Garlic Mustard's native range, indicating that this "novel weapon" in the invaded range explains Garlic Mustard's success in North America.[18] Additionally, because white-tailed deer rarely feed on Garlic Mustard, large deer populations may help to increase its population densities by consuming competing native plants. Trampling by browsing deer encourages additional seed growth by disturbing the soil. Seeds contained in the soil can germinate up to five years after being produced (and possibly more).[19] The persistence of the seed bank and suppression of mycorrhizal fungi both complicate restoration of invaded areas because long-term removal is required to deplete the seed bank and allow recovery of mycorrhizae."

And above, another reason it's so pernicious. Like the monster in a movie, just because you gave it a good whack doesn't mean its dead! All my piles of garlic mustard turned their growing tips upward after a day or so, continuing to flower and set seed! You cannot compost these unless it is well before, well before, flower formation. Don't think chopping them up is good either, and stay clear from the weed whacker if you find yourself falling behind -it will just distribute the very viable seed. I found that even picking up piles created great opportunities for the seed heads to get stuck to my muddy shoes and transport elsewhere.

I am no fan of Monsanto, nor pesticides of any kind. That said, I am considering the use of glyphosate during a dry period of early or late winter when there is no snow and the garlic mustard is green. It is about the only thing that is up at the time and from what I understand (considering how everyday the use of this product is on our food crops) it will have little obvious effect on plants dormant at that time. I will test this theory, and be considerate as can be.

I am sad to say I did not get to every major patch of garlic mustard growing this year. The back swale comes to mind, and everything over the bridge was completely untouched by us. Now that the woods are summering, the mosquitos prevalent, and the seed heads likely to break, I may just leave the thousands that remain until autumn.


  1. Do not envy you this enormous job! But, you really do need to intervene if it has such a strong foothold. Roundup was made for times like these. Sometimes you just gotta do what you gotta do. Here it's kudzoo.