H

Hardscape – The pavement, irrigation system, and other structural elements of a landscape.

Heading Cut – Pruning a currently growing of one-year shoot back to a bud, or cutting an older branch or stem back to a stub or lateral branch not sufficiently large enough to assume the terminal role.

Heart Rot – Decay present in the heartwood (center) of a tree.

Heartwood – Darker-colored wood toward the center of a stem or root that has become physiologically inactive. It no longer functions for the transport of water and nutrients, but may be a site for storage.

Herbicide – A chemical that kills plants or inhibits their growth, intended for weed control.

Host – A tree that harbors an insect or disease.

Hydraulic Soil Evacuation – A process by which high pressure and high volume water stream is used to dislodge soil around roots and a large truck-mounted vacuum unit is used to remove the slurry.