Persian Shield Winter Leaf Drop Is Normal

Persian Shield (Strobilanthes dyeranus) drops leaves and goes dormant in winter, even in North Florida (zone 9). It's hardy to zone 9 but acts like a herbaceous perennial — dies back, returns in spring. North of zone 9, bring indoors or treat as annual. When dormant, don't water.

University of Florida has a detailed care sheet. This is normal behavior, not death.