T-budding - a grafting technique that consist of placing a bud from one plant into a T shaped cut in the bark of another tree. It is sometimes called shield budding.
tall fescue - a trurfgrass species that may be either:

1) a lawn weed when it is introduced randomly by a bird or the wind. It forms a somewhat circular pattern of wide, coarse texture, lighter colored grass which conflicts with the other grass species.

2) an improved turfgrass species that is adapted to shade, droughty soils and takes wear well. New cultivars of this species have been developed for use in general purpose lawns.
taproot - a tap root is usually the main root of a plant that goes deep into the ground. Most plants do not develop a true taproot but a few such as walnut, sassafras and oak trees do which makes them more difficult to transplant.
taxonomy - the branch of science that deals with the identification, classification, and naming of plants or animals.
temperate region - a zone of the world which routinely experiences freezing temperatures nearly every year.
See tropical and subtropical
tender - in plants, a term used to describe a plant that may not be able to survive in local conditions. It is often applied to plants that cannot withstand sub-freezing temperatures but it could also apply to those that cannot survive hot, dry summers.
 
tendril - vines climb by a number of mechanisms. Tendrils are modified stems that coil around objects and support the stem.
tepal - most flowers have sepals and petals that can be distinguished from each other. They are different colors or shapes. If they appear to be the same structure and cannot be distinguished from each other, the structure is called a tepal. They tend to be common in many groups of monocotyledons such as hostas.

When the sepals and petals of a flower are indistinguishable, they are referred to as tepals. Tepals are common in many groups of monocots such as Hostas.
terminal bud - a bud growing at the end or tip of a branch or stem.
tetraploid - most plants have two sets of chromosomes (diploid) and get one set from each parent during sexual reproduction. Through plant breeding or other manipulation, some plants are produced which have four sets of chromosomes and are called tetraploid.

Tetraploid plants tend to have thicker parts including leaves, stems and petioles. Their flowers tend to be larger and the thicker stems make them more upright plants. The color of variegations and base leaf color tend to be deeper in tretraploids also.

See haploid, diploid, triploid and tetraploid.
texture - 1) visual texture is determined by the relative size of plants or plant parts. Large leaves, flowers or shedding bark show coarse texture while thin leaves, small flowers and smooth bark indicate fine texture

2) tactile texture is determined by the feel of a plant part. Smooth and rough tend to describe a range of textures.

3) soil texture refers to the size of the particles that make up the soil. Those with large amounts of sand or grit are coarse while more clay tends to be fine textured.
 
thatch - a layer of organic matter that forms between the soil and the surface of the lawn. It is made up of both living and dead material such as stems, roots and rhizomes, which are resistant to biological breakdown. Is NOT made up of grass blades from mowing.
thinning - a pruning method that controls size and rejuvenates the plant, making it more vigorous, healthy and strong.
thinning cut - removing a branch back to its point of origin; typically has a dwarfing effect on the plant. Thinning out. In pruning, the term means removing entire branches, either large or small ones, to make a plant or tree less dense. In speaking of seedlings or young plants, thinning out means removing enough plants so that those remaining have room to spread leaves and roots.
three-cut method - whenever a saw is used in pruning landscape plants, either a two or three cut method should be used. This means that the first cut is up from the bottom of the branch. Depending on the size of the branch, you then make the second cut from the top down. Or, if the branch is quite heavy, you make the second cut about a foot out from the trunk and then the third cut goes downward just outside the branch collar and joins up with the first cut from below.

If you just cut downward with one cut, at some point, the weight of the branch will cause the cut to continue by itself. This will rip the bark from the tree beneath the cut leaving an unsightly scar and opening the tree to infections. This is avoided by making the first cut upward to break the bark on the lower side of the branch.
threshold - each person and situation will determine the amount of damage from a pest or disease that will be tolerated before applying a control measure. This threshold may be zero damage or you may decide to do nothing or anything in between. The key is to not automatically feel that every problem needs to be sprayed.
 
tiller - 1) a plant that springs from the root or bottom of the original stalk, referred to as an offset or daughter plant. Certain trufgrass species spread by adding tillers to the side of their crown.

2) a machine built specifically for turning over the soil to prepare it for planting.

tilth - the physical condition of soil.
tip layering - method of propagation in which the ends of canes or branches of shrubs are buried in the soil causing new plants to develop from them
tissue - a group of cells, usually of similar structure, that perform the same or related functions. For example, xylem and phloem are vascular tissue of plants.
tissue culture

- a high tech form of asexual plant propagation. Small pieces of a plant are prepared under completely sterile conditions to prevent contamination by rotting fungi. The pieces are grown in a mixture called agar in test tubes under highly controlled conditions and, if everything works properly, they multiply rapidly. Using this process, thousands of cloned plants may be produced in a very short period of time.

Hostas - Due to the growth hormones used during the tissue culture process, there is an increased chance of mutations or "sports" appearing in a large group of plants that originate from a single mother plant (explant). As a result, many new cultivars of hosta have been introduced after they were found in the tissue culture process. These are often called "tissue culture sports".
topdressing - a method of applying soil amendments or fertilizers by scattering them over the soil surface while the plants are growing.
 
topping 1) item such as pepperoni that may be put on top of a pizza

2) a drastic pruning of the entire top of tree to bring the height down to a desired level. This is generally not a recommended pruning technique for landscape plants.
top soil - the uppermost layer of soil, usually characterized by a higher quantity of organic matter and nutrients than the subsoil.
toxicity - a measurement of the toxicity of a substance to an organism. This may apply to a pesticide, poisonous plant or anything else.
trace elements See microelements
translocation - the movement of water, nutrients, carbohydrates and other chemical substances dissolved in water through the system of the plant
transpiration - evaporation from the surface of a leaf.
transplanting - moving a plant from one growing environment to another
 
trellis - garden structure generally made of crossing pieces of wood and posts that is intended to support climbing plants.
tree - a woody plant that has a distinct individual central trunk.
trickle irrigation - method for watering plants through a tube or hose that has micropores that releases water at a slow pace directly to the soil around plants.
triploid - most plants have two sets of chromosomes (diploid) and get one set from each parent during sexual reproduction. Through plant breeding or other manipulation, some plants are produced which have three sets of chromosomes and are called triploid.
tropical - an area of the world which NEVER has freezing temperatures 
See temperate and subtropical
tropism - general term for the plant's response to various external stimuli. Phototropism is the attraction to the light. Geotropism is the attraction that pulls the roots downward.
 
true leaves - the first leaves that emerge from a seed are called seed leaves. They may have little resemblance to the mature leaves of the plant. The first set of leaves that are representative of the species are called true leaves.
trunk - the major vertical above ground stem of a tree
truss - cluster of flowers usually growing at the terminal end of a stem or branch in plants such as rhododendrons.
tuber - a thickened, short underground stem, as in the potato. Like a stem, it has buds (eyes) that may turn into either roots or stems.
tuberous root - a thickened lateral root which fills up to store carbohydrates and sugars to help the plant get off to a start the next spring. There are no buds on roots as there are on tubers. Example is dahlias.
tubular flowers Flowers that resemble a bell being held with the opening in an upward direction.
 
tunicate bulb - a bulb that has a series of concentric layers of a papery substance on the outside. Tulips are a tunicate bulb.
turfgrass - a term which differentiates species of grass such as Kentucky bluegrass, perennial ryegrass and fine fescue that are commonly used in lawns versus those larger types that we call ornamental grasses.
turgor pressure - internal pressure within plant cells that keeps them firm and solid. Lack of water reduces turgor pressure and causes the plant to wilt.
two cut method - whenever a saw is used in pruning landscape plants, either a two or three cut method should be used. This means that the first cut is up from the bottom of the branch. Depending on the size of the branch, you then make the second cut from the top down.

If you just cut downward with one cut, at some point, the weight of the branch will cause the cut to continue by itself. This will rip the bark from the tree beneath the cut leaving an unsightly scar and opening the tree to infections. This is avoided by making the first cut upward to break the bark on the lower side of the branch.
 

 

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