Troubleshooting
Intermediate Polypody problems — and how to fix them
Intermediate Polypody (Polypodium interjectum) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Summer frond yellowing
Partial summer dormancy is natural for this species. Reduce watering in summer; do not over-compensate with more water, which will rot the rhizome. New growth resumes in autumn.
Poor growth indoors
This species prefers cool conditions. A warm (above 22°C) centrally heated room suppresses growth. Move to the coolest available position indoors or grow outside in a sheltered spot.
Vine weevil (outdoor)
Vine weevil grubs eat rhizomes when grown in outdoor containers. Apply biological control (Steinernema kraussei nematodes) in late summer to early autumn when soil is warm enough (above 5°C).
Prevent intermediate polypody problems before they start
Most intermediate polypody issues are care-mismatch, not bad luck. Dial in the basics:
Looking for intermediate polypody in general rather than its problems? Read the full intermediate polypody care guide — light, water, soil and feeding.
Intermediate Polypody problems — FAQ
Why is my intermediate polypody summer frond yellowing?
Partial summer dormancy is natural for this species. Reduce watering in summer; do not over-compensate with more water, which will rot the rhizome. New growth resumes in autumn.
Why is my intermediate polypody poor growth indoors?
This species prefers cool conditions. A warm (above 22°C) centrally heated room suppresses growth. Move to the coolest available position indoors or grow outside in a sheltered spot.
Why is my intermediate polypody vine weevil (outdoor)?
Vine weevil grubs eat rhizomes when grown in outdoor containers. Apply biological control (Steinernema kraussei nematodes) in late summer to early autumn when soil is warm enough (above 5°C).