The answer to 'why is my mulch drainage problems' is that improper mulch application or poor soil drainage can cause mulch to become waterlogged and prevent proper drainage. Symptoms include standing water, muddy soil, and poor plant growth. To solve this, you may need to adjust the mulch depth, improve soil drainage, or replace the mulch entirely.
Mulch should be applied in a 2-4 inch layer around plants, with a slight slope away from the base to allow water runoff. If the mulch is too thick, it can prevent water from properly draining into the soil. Poor soil drainage from compacted soil or clay-heavy earth can also lead to waterlogged mulch. In these cases, you may need to aerate the soil or install drainage systems like French drains to improve drainage.