Impatiens-suspected bacterial wilt
Every year I plant impatiens in a large planter in front of my house. Usually, they are gorgeous and thrive, getting large and bushy, filling up the entire space. The only probelm is fighting off the deer. This year two batches have died: the plant stems fall over and appear to have been severed at the ground level. I do not see any oozing yellow stuff though. What is causing this and how can I prevent it next year? Or treat it now?
It could be cutworms. Neem oil should help. Here is more information to help you: https://www.gardeningknowhow.com/ornamental/flowers/impatiens/impatiens-problems.htm