Tall fescue - a coarse, clump-forming turfgrass that tolerates low fertility, heavy wear, heat and drought and has good insect and disease tolerance. Young seedlings are not cold tolerant, but mature plants survive most Ohio winters.
Taproot - a stout, tapering primary root that has limited side branching or fine roots.
Temperate - moderate; the zones between the tropics and the polar regions of the earth.
Tender Perennial - A true perennial with a predictably long life in the proper climate, but unable to endure the extremes of the climate in which it will be grown. Many of the plants we know as annuals are actually tender perennials.
Tendril - a slender, coiling modified leaf or leaf part. These help plants climb.
Tepee - a tripod of stakes used to support climbing plants.
Terminal bud - large, vigorous buds at the tips of stems.
Terrace - a series of flat platforms of soil on the side of a hill, rising one above the other.
Thatch - an intertwined layer of dead and living roots, stems and blades of grass plants. It holds water, pesticides and fertilizer like a sponge, preventing them from reaching the roots.
Thorax - the middle of the three major divisions of the arthropod body.
Topiary - training, cutting and trimming of plants into ornamental shapes.
Top dress - To scatter material at the base of a plant without working it into the surrounding soil.
Topsoil - uppermost layer of soil, usually darker and richer than the subsoil.
Toxicity - intensity of a poison.
Transpiration - the loss of water from plant tissues in the form of vapor.
Transplanting - digging up a growing plant from one location to plant it in another location.
Trellis - a frame of latticework used as a support for climbing plants.
Tropical - regions of the earth lying between the Tropic of Cancer and the Tropic of Capricorn extending around the equator where the temperature and humidity are high.
Trunk - the main stem of a tree, shrub or vine.
Tuber - an enlarged, underground stem that stores food.
Turgid - the condition of a cell, tissue or plant when it is filled with water so that it is firm; not wilted.
Umbel - an inflorescence in which a number of flower stalks or pedicels, nearly equal in length, spread from a common center.
Understock - the part of a plant to which a graft is attached.
Variegated - plant parts having different pigments resulting in more than one distinct color or shade on the foliage.
Variety - a subdivision of a species; occurs through natural hybridization.
Vascular system - the tissue in a plant that moves fluids through the plant.
Vector - an organism that transmits a disease-causing pathogen.
Vegetable - A plant cultivated for an edible part
Vegetative - plant parts and processes concerning growth and nutrition and not reproduction.
Venation - the pattern of veins.
Vermiculite - a clay mineral used in its heat expanded form as a bedding material for young plants
Viable - capable of growing or developing.
Virus - a group of submicroscopic infective agents that are considered nonliving complex molecules.
Warm-season crops - crops that are harmed by frost and do not grow well until the temperatures are in the 70s.
Whip - a very young tree that still has a flexible trunk.
Wide-row planting - growing the smaller vegetable crops in a space up to 3 feet across to better utilize space while reducing weeding.
Wilting point - the amount of water in a soil when a plant cannot obtain enough water to remain turgid.
Winter dormancy - The state of reduced growth and function which permits the plant to survive the extremes of winter.
Winter over - Same as overwinter To live through the weather conditions of winter and return to vitality the following year.
Witches'-broom - a dense, bushy growth of branches and foliage caused by a parasitic fungus and mites or poor pruning techniques.
Work up - To clear a space of undesirable plants and other materials, dig deeply, top with amendments and work the amendments thoroughly through the soil. After working up, the bed must be brought to grade, or smoothed to the desired finished surface.
Xeriscaping - Pioneered in Denver, xeriscaping is a series of practices used to reduce the amount of supplemental irrigation used in gardens. The practices need to be carefully considered with the climatic conditions of the particular area in which the garden is sited.
Xylem - the part of the vascular system that moves water and minerals through the plant.
Zones, Cold/Heat - The American Horticultural Society has developed maps of the amount of heat expected in a given area or zone. Individual plants are rated for their heat zone tolerance. The United States Department of Agriculture long ago developed a map of the amount of cold expected in a given area or zone. Individual plants are rated for their cold zone tolerance.