Metal step flashing, extending up from the roof six inches, can be installed at the base of combustible siding. Integrate it with the siding to avoid moisture-related problems.
The combination of ignition-resistant shingles on this porch with flashing helps protect the siding from smoldering embers.
For flashing to be effective, use at least two or more inches on top of your siding.
If you can't trim your siding, you can always add more flashing on top to offer extra protection.