My biggest garden challenges:
1. Planting in GA red clay
2. Critters- the rabbits, chipmunks, squirrels
3. Summer heat and humidity
4. Deer
5. Black spot
6. Inconsiderate neighbors and their pets
7. Aphids
8. Japanese beetles
9. Weeds
The biggest challenge of all is trying to grow tropical plants that won't survive in my zone, and having too many of them to take into the house during the fall, and back out during the spring
but I still love them anyway.