Drought also reduced seed set following flowering, often eliminating it altogether. After adding one year for the seedling year of plants first spotted as juveniles, the average life span of these plants is 3.58 years. Boring insect larvae infest lower stems killing many mature plants. Drought kills seedlings and some young plants not well enough established to withstand its stress. Very wet summers lead to the death of many large plants for unknown reasons but also lead to increased seed germination and seedling establishment the following spring.
Drought reduces seed set.
Fire can destroy seed still in pods but scarifies and promotes germination of some seed as well.