Sunrise.... Sunset

I'm not having much luck with my Sunflowers this year. 

Back in May.... April?   First batch I put in, maybe 5, were all eaten within about 2 hours of them going in. 

Next batch didn' really take.  

Next batch got planted. I covered them up.  I waited til they were at least 3 ft high before I removed the covers.   I had two magnificent tall plants either side of my gate.   And about 7 or 8 smaller ones between them. 

The two large ones have gone.   One got lost in the wind the other week. I think I tied it too hard, and it got sliced by the twine.   The other tallest one collapsed last night. I'm unsure why. 

I'm starting to suspect fowl play.