Answer: Unfortunately all you can do is decide which one you want, mulch or rocks, clear out the other and start over. If it were me, I would go for the mulch. Mulches like shredded bark, pine chips, cocoa hulls, etc. are more benefical to your soil. They decompose over time and that enriches the soil. Rocks can heat up quite a bit in the summer and make the soil too warm for tender plant roots (which prefer cooler conditions). If it is easier or more desirable to you, you could just add some fresh rocks on top of the older rocks for a renewed look.
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