Glossary - Landscape Terms

Glossary – Landscape Terms

Acid Soil
A soil with a pH lower than 7.0 is an acid soil. (a soil pH higher than 7.0 is alkaline) Basically, pH is a measure of the amount of lime (calcium) contained in your soil.
A measure of land totaling 43,560 square feet. A square acre is 208.75 feet on each side.
Loosening or puncturing the soil to increase water penetration.
Air Layering
A specialized method of plant propagation accomplished by cutting into the bark of the plant to induce new roots to form.
Alkaline Soil
A soil with a pH higher than 7.0 is an alkaline soil. (a soil pH lower than 7.0 is acidic) Basically, pH is a measure of the amount of lime (calcium) contained in your soil.
Allowable Depletion
The decrease in soil reservoir capacity you are willing to allow before adding irrigation water. A medium value turf is typically managed at 50% AD, whereas a low value turf may be managed at a 75% AD.
Any substance, such as manure, peat or mulch, used to alter the properties of soil.
A plant that germinates, grows, produces flowers and seeds, and dies within one growing season.
Aquatic Plants
Plants which grow in, live in, or live on the water.
A garden with a large collection of trees and shrubs cultivated for scientific or educational purposes.
Available water
The difference in the amount of water contained in soil at field capacity and the amount at the permanent wilting point.

Soil used to fill a planting hole after the plant has been positioned. Amended soil is often used as backfill.
Balled and burlapped (abbrev. B & B)
A way of packaging plants in which the roots are contained in a ball of soil held together in burlap.
Bare Root
Plants offered for sale which have had all of the soil removed from their roots.
Bedding Plant
Plants (mainly annuals), nursery grown and suitable for growing in beds. Quick, colorful flowers.
Bench mark (BM)
A fixed point with a known elevation.
A plant that completes its life cycle in two years.
Vegetables which quickly go to flower rather than producing the food crop. Usually caused by late planting and too warm temperatures.
The art of growing carefully trained, dwarf plants in containers.
Branch collar
Trunk tissue that forms around the base of a branch where it attaches to the main stem or a lateral. As a branch decreases in vigor or begins to die, the branch collar becomes more pronounced.
Modified leaves growing just below a flower. Often confused with the flower itself.
Branch ridges
The raised area of bark in the branch crotch that makes the junction of the branch wood and trunk wood.
To scatter seed, fertilizer or other material over the ground.
Early stages of development of a flower or plant growth.
The thickened underground storage organ of the group of perennials which includes daffodils and tulips.
Butterfly container roots
A method of loosening a tightly bound root ball on container-grown plants. A vertical cut is made from the bottom of the root ball part way up.

The diameter of a tree trunk measured 6″ (15 cm) above ground level for trees up to 4″ (100 mm) caliper and 12″ (30 cm) above the ground for larger sizes.
The thin membrane located just beneath the bark of a plant.
A stem of a shrub. Multi-caned shrubs are preferred because of their fuller form.
The green pigment in leaves. When present and healthy usually dominates all other pigments.
Very fine soil particles. Clay soils (soils containing a high percentage of clay particles) are often called heavy soils and are characterized by slow movement of water through the soil. Clay soils can be improved with soil amendments such as manure, peat or mulch.
An organic soil amendment resulting from the decomposition of organic matter.
A group of plants, mostly evergreen, that produce their seeds in a cone.
Container stock
Trees or shrubs packaged with their roots and growing medium in a plastic or peat-fiber container.
The point at which a plants roots and top join. (usually at soil level)

A level surface used as a reference for elevations.
Dead Head
The process of pinching off used or spent blooms to keep the plants well groomed and to prevent them from setting seed. This will promote continued bloom.
A tree or shrub that loses all of its leaves at once, usually in the fall.
A pathogen that impairs the normal function or development of a plant.
Drip Line
The circle which would exist if you drew a line below the tips of the outer most branches of a tree or plant.

Evapotranspiration (ET)
The combination of evaporation (water loss from land and water surfaces) and transpiration (water loss from plants).
Plants that do not lose all of their leaves at once. Evergreens can be conifers or broad-leaved.

The application of nutrients to promote plant vitality. Organic or inorganic plant foods which may be either liquid or granular used to amend the soil in order to improve the quality or quantity of plant growth.
Field capacity
The point at which soil becomes saturated and cannot absorb any more water.
Foliar Feeding
Fertilizer applied in liquid form to the plants foliage in a fine spray.

To cut or constrict bark so that growth is slowed or stopped. By inhibiting the movement of nutrients, girdling can harm or kill plants.
A measure of the change in elevation in relation to the change in distance. Gradient is expressed as a decimal and is always a positive number.
The uniting of a short length of stem of one plant onto the root stock of a different plant. This is often done to produce a hardier or more disease resistant plant.
A rope or wire used as a tree support.

A layer of hard or compacted soil impenetrable to plants roots, water and nutrients.
Plants with soft, non-woody stems. Generally refers to plants that die back to the ground each year.
A substance used to kill plants. A herbicide can be selective (designed to kill a narrow range of plants) or non-selective (designed to kill any plant it contacts). Herbicides can also be pre-emergent or post-emergent.
A cross between two plants of different variety, species or genus. Hybrids are usually created to produce plants with specific characteristics, such as disease resistance, unique flower color, etc.

Infiltration rate
The rate at which water is absorbed into the soil. Clay soils have low infiltration rates; sandy soils have high infiltration rates.
A substance used to kill insects.
The application of water to the soil to nourish plants.

Lateral branch
A branch growing out of a main trunk or stem.
Lateral line
An irrigation pipe that goes from a control valve to sprinkler heads, emitters, etc.
The dominant vertical branch that extends above the other branches.
A soil type composed of clay, silt and sand particles in relatively equal amounts. Loam is considered ideal for plants because it drains well but does not dry out quickly.

An irrigation line that receives water from the source and distributes it to the control valves.
A nutrient required by plants in small or trace quantities. Does not include the major plant nutrients (nitrogen, phosphorus and potassium).

Organic matter (abbrev. OM
Naturally occurring material such as manure, sewage sludge, peat, grass clippings, etc. Organic matter is often used as a soil amendment.

A plant that lives for more then two years.
Permanent wilting point
The point at which plant roots can no longer extract water from the soil.
Something that can negatively impact plants. Weeds, undesirable insects and diseases are all considered pests.
A substance used to kill pests.
The measure of a soil’s acidity or alkalinity on a scale of 0 to 14. A pH of 7 is considered neutral. A pH under 7 designates acidic soil, while a pH over 7 designates alkaline or basic soil.
Complex tissue that conducts food in woody plants.
The process by which plants produce their food using water, carbon dioxide and energy derived from sunlight.
Pore space
Spaces within soil that contain air and water.
Post-emergent herbicide
A chemical that kills plants after they have emerged from soil.
Pre-emergent herbicide
A chemical that kills plants after seeds have germinated but before plants have emerged from soil.

Root bound
The condition in which a plant’s roots have become tangled and matted from growing in a container too long. Once planted, a root bound plant will not grow well or anchor normally. Tall plants are in danger of toppling in high winds.

Large soil particles. Sandy soils (soils containing a high percentage of sand particles) are characterized by rapid water movement through the soil. Sandy soils can be improved with soil amendments such as manure, peat or mulch.
To cut, scratch or losen roots or soil before planting to prevent plants from being root-bound.
The particles of sand, silt and clay that make up a soil.
Soil particles that are larger than clay and smaller than sand.
Soil reservoir
The amount of water the soil can contain measured down to the plant root. The soil reservoir multiplied by the available water per foot is the soil reservoir capacity.
A bog moss which is collected and composted. Most peat moss is composed primarily of sphagnum moss. This moss is also packaged and sold in a fresh state, and used for lining hanging baskets and air layering.
The reproductive cell of ferns, fungi and mosses. (these plants do not produce seeds)
The practice of driving a stake into the ground next to, and as a support for a plant. When attaching the plant to the stake, be sure that it is tied loosely so it doesn’t strangle the stem. When staking a potted plant, the stake should be set into the planter before the plant is added.
A growth originating from the rootstock of a grafted plant, rather than the desired part of the plant. Sucker growth should be removed, so it doesn’t draw energy from the plant.
A chemical which is absorbed directly into a plants system to either kill feeding insects on the plant, or to kill the plant itself.

Tap Root
The main, thick root growing straight down from a plant. (not all plants have tap roots)
Tender Plants
Plants which are unable to endure frost or freezing temperatures.
The twisting, clinging, slender growth on many vines, which allows the plant to attach themselves to a support or trellis.
The layer of dead stems that builds up under many lawn grasses. Thatch should be removed periodically to promote better water and nutrient penetration into the soil.
Removing excess seedlings, to allow sufficient room for the remaining plants to grow. Thinning also refers to removing entire branches from a tree or shrub, to give the plant a more open structure.
A method of pruning and training certain plants into formal shapes such as animals.
The top layer of native soil. This term may also apply to good quality soil sold at nurseries and garden centers.
The release of moisture through the leaves of a plant.
The process of digging up a plant and moving it to another location.
A flat underground stem which stores food and plant energy and from which a plant grows. (e.g. Dahlias)

Leaves which are marked with multiple colors.
The mineral ‘mica’ which has been heated to the point of expansion. A good addition to container potting mixes, vermiculite retains moisture and air within the soil.