I live on a half acre in central Utah that we are landscaping,and my husband has been building a retaining wall with local stones from our area that are covered with beautiful lichen. The wall needs to get finished before we can complete anymore landscaping and the yard is mostly weeds. My question is about using broadleaf weed killer around the lichen. We have a big bindweed problem here and I was wondering if we use the weedkiller around the wall to help control the bindweed (until we can get the grass in) if it would also kill or damage the lichen. Any advice would be appreciated. Thank You!