Types
Pine bark mulch comes in fine grain/sawdust, shredded, and wood/bark chip “nugget” varieties. Hardwood mulch comes from trees like maple and oak, and is usually shredded. It may be made from bark, wood, or both.
Durability
While pine bark mulch in the wood or bark chip form can last one to two years, finer grained pine bark and hardwood mulches usually last only one year.
Rain Effects
Pine bark nuggets can wash away in heavy rain; finer grained varieties of hardwood and pine bark mulch will adhere to the soil.
Problems
Hardwood bark mulches can grow harmless but potentially unattractive fungi. Water thoroughly after applying hardwood bark mulch to encourage beneficial bacteria and discourage fungi growth. Raking away hardwood mulch and adding pine bark mulch eliminates fungi.
Application
Whichever mulch you use, weed thoroughly first and then apply a layer 2 to 4 inches thick to prevent weed growth. Both pine bark and hardwood are ideal for weed suppression.