I purchased a packet of different humming bird flower seeds and spread them around so there are different plants growing in different spots in the garden (which is about 8 feet by 2 feet) the plants have just recently come up and it said on the news there is a frost advisory tonight, I have never dealt with this before, do I need to protect them? How do I? I can't remember my zone but I live in Central Minnesota, around the bottom of Mille Lacs County, it is already late here and would like an answer so I can get out and take care of them before it is to late, please answer.