droopy plant

I am a first year hop grower. I have a few hop plants and they all seemed to be doing fine. My two cascades are doing awesome! I also have a nugget that is doing great also but my willamette is having some problems. At first it seemed to have a potassium deficiancy wich I corrected and seemed to be doing better but today the leaves looked droopy and the stem holding the leaf is soft and not rigid like it was before. Almost like is has not had water but I know that is not the problem. what could be causing this? This is a first year but it is about 10 feet tall. The other plants look fine? Any help would be awesome, thanx.

How often do you water and how much? Could be too much water.

I water depending on the heat and other factors but it did rain a lot last night. I thought is could be too much water just was not sure since the other plants were still looking fine.