>> It then started raining and rained at least some every day for over a week.
it might be that several days in a row is too long. And yet, most seed pods must be able to survive SOME rain, or they would never come back after a rainy fall.
Or it may be Nature's usual "numbers game".
Produce 100,000 seeds.
90% rot before dropping.
Still have 10,000 seeds.
90% of those rot on the ground or are eaten.
Still have 1,000 seeds.
90% don't germinate
Still have 100 seedlings.
90% are eaten by bugs, rabbits & deer.
Still have 10 adult plants.
Oh my Gosh! A 99.99% death rate would still result in a plant population explosion.