Bark mulches vary, but all are attractive, durable and suitable for foundation shrub plantings. Contact with wood framing is to be avoided, since bark can be a termite vector. Cocoa shells have some value as a fertilizer and resist blowing in the wind. Their high potash content harms some plants, so they should not be applied to a depth greater than 2 inches. Cocoa shells may have an offensive odor.
Coffee grounds contain some nitrogen.
It is also a good organic amendment for tilling into the soil after the growing season ends. Ground corn cobs are a good mulch. Some find their light color objectionable. Other uses for ground corn cobs, such as in feeds and mash, tend to limit the supply for mulching. Leaves are free, readily available in many areas, release some nutrients upon decomposition and spread easily.