Hardwood Mulch

The malpractice of piling mulch high on tree stems to approximate the look of a volcano is well underway in Ohio. This horticultural horror, commonly known as a “mulch volcano” or “volcano mulch,” produces a range of detrimental effects, including reshaping tree root systems and interfering with water infiltration and retention.

When done right, organic mulch, particularly hardwood bark mulch, will provide a wide range of benefits to trees and other woody ornamentals. When done wrong, it can produce a range of detrimental effects that wreak havoc on tree health from vascular strangulation to moisture starvation.

The vast majority of the trees and shrubs used in Ohio landscapes evolved in ecosystems with soils topped by an organic layer. Think forest and grassland soils. Aged hardwood bark mulch serves as a stand-in for leaf litter found beneath trees in forests. However, if a little is good, more is not better.