The impervious layer of soil or clay lying beneath the topsoil.

Constructed elements of a landscape, such as decks, walls fences and driveways.

Refers to plants that have the ability to survive prolonged exposure to freezing temperatures.

Cutting an older branch or stem back to a stub or twig.

A documented phenomenon that takes place in urban and suburban areas where temperatures are as much as 10 degrees Fahrenheit (6 degrees Celsius) hotter than in rural areas.

A method of protecting a plant by placing its stems in a shallow trench over winter.

Temporarily setting a plant into a shallow trench and covering the roots with soil to provide protection until it is ready to be permanently planted.

Seeds that have traditionally been saved by families, generation after generation. These seeds have many qualities and are desirable for their high qualitly and taste.

Describes a plant with soft rather than woody tissues.

A pesticide formulated to kill or control plants.

The sticky secretion produced by sucking insects such as aphids.

A long, thin, metal post with a perpendicular ring of wire at the top, which serves as a support for tall-growing flowers.

The brown or black organic part of the soil resulting from the partial decay of leaves and other matter.

The offspring of two plants of different species or varieties of plants. Hybrids are created when the pollen from one kind of plant is used to pollinate and entirely different variety, resulting in a new plant altogether.

The science of growing plants in mineral solutions or liquid, instead of in soil.