Earlier this year, Kate’s sunflowers in the hort greenhouse were having an issue where the stem right under a maturing flower would darken and wither. The flower would droop down and gradually die. This was particularly annoying when trying to collect seed from crosses.

I’ve been growing H. bolanderi in the hort greenhouse and my plants seemed to have the same issue. When I saw this happening I trimmed off the drooping flowers, which occurred on about 10 of 24 plants. I also noticed that the new leaves were browning at the tip, a symptom of nutrient burn, so I flushed the soil by excessively watering it once.

A week later my plants no longer had any head droop and some flowers that seemed iffy before were fine. The leaf tip browning also reduced. I’m not sure if flushing the soil was the cure or something else happened at the greenhouse or it has only temporarily subsided. This is just something to try if you have the same problem.

One interesting note is that my plants are serpentine adapted and Kate’s are dune plants, which are both fairly nutrient poor soils. Perhaps they are extra susceptible to nutrient burn.