Glossary
- Abiotic factors
-
Nonliving factors such as nutrient deficiencies and water or temperature stress
- Absorption
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Process by which substances, particularly water and minerals, are moved into the plant. This occurs mainly through the roots in the tip region where root hairs are present, but it may also occur through leaf surfaces.
- Accent
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Focal point, something that deliberately stands out from the overall landscape
- Adsorption
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Attachment of dissolved or gaseous pollutants to the surface of solids. For example, odors from freezers and refrigerators are adsorbed to baking soda.
- Adventitious buds
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Buds arising at sites other than in the terminal or axillary position
- Aggregate fruits
-
Fruits that come from a single flower with many ovaries
- Alternate
-
Leaf arrangement where leaves are arranged in alternate steps along the stem with only one leaf at each node.
- Ametabolous
-
An insect that undergoes slight or no metamorphosis
- Angiosperms
-
Flowering plants that produce seeds enclosed in a fruit
- Annuals
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Plants that pass through their entire life cycle from seed germination to seed production in one growing season, then die
- Anvil style shears
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Pruning shears with a sharpened blade that cuts against a broad, flat plate
- Aquifers
-
Geologic formation that holds and yields usable amounts of water. The water in an aquifer is called groundwater. Aquifers may be categorized into confined aquifers and unconfined aquifers.
- Atmospheric humidity
-
Amount of water vapor in the air, expressed as a percentage of the moisture saturation of air
- Autotrophy
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Ability of plants to manufacture their own food
- Axillary buds
-
Buds arising in the leaf axils
- Balance
-
Design principle that refers to an aesthetically pleasing integration of elements; a sense of one part being of equal visual weight or mass to another
- Bare root plants
-
Perennials that are dug up during their dormant season and sold without soil around the roots
- Bark
-
A nontechnical term that refers to all the tissues outside the vascular cambium, including the periderm
- bedding plants
-
Encompass a wide variety of non-hardy, seasonal things like annuals, tropicals, herbs, vegetable transplants, etc.
- Bermudagrass
-
A fine-bladed, warm-season grass with exceptional drought tolerance that aggressively creeps by both rhizomes and stolons.
- Biennials
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Plants that start from seeds and produce vegetative structures and food storage organs the first season and flowers, fruit, and seeds the second season
- Binomial nomenclature
-
System of naming organisms in which the name is composed of two terms
- Biodiversity
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The variety of genes, species and ecosystems in the aggregate, across the larger landscape.
- Biological control
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Using living organisms (i.e., natural enemies) to reduce pest populations (typically insects and weeds)
- Biotic
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Living agents such as fungi, nematodes, bacteria, and viruses
- Blade
-
Expanded, thin structure on either side of the midrib of a leaf. The blade is usually the largest and most conspicuous part of a leaf.
- Bolt
-
flower prematurely
- Bracts
-
Modified leaf or scale with a flower or flower cluster in its axil. Often brightly colored, as in poinsettias.
- Branch
-
A stem that is more than one year old and typically has lateral stems
- Branch bark ridge
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Prominent ridge of raised bark that forms within the branch crotch
- Branch collar
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The swollen area that forms around the base of a branch, often appearing a bit swollen
- Broadleaf evergreens
-
Angiosperms trees that retain foliage throughout the year
- Bud
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Small package of partially preformed tissue which becomes leaves/stems or flowers
- Budding
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The union of one bud and a small piece of bark from the scion with a rootstock
- Bulbs
-
Shortened, compressed, underground stems surrounded by fleshy scales (leaves) that envelop a central bud located at the tip of the stem
- Bypass pruners
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Pruning shears with two blades that cut like scissors
- C3 plants
-
Found in temperate to cold climates with high moisture environments and represent the majority of plant species. They typically are slower-growing plants than C4 plants and use CO2 less efficiently as a result of an energy-wasting process called photorespiration.
- C4 plants
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Found in hot, dry, subtropical to tropical environments. They are fast growers and have higher rates of photosynthesis than C3 plants. Because C4 plants do not photorespire, they are more efficient in fixing CO2 than C3 plants.
- Calyx
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The sepals of a flower
- CAM plants
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Found in very hot dry desert areas. Like C4 plants, CAM plants are not susceptible to photorespiration because, unlike C3 and C4 plants, they open their stomata at night, thus conserving water and fixing CO2 and storing it for use during the day to make sugar.
- Cambium
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In woody plants, the layer of cells located between the wood and bark of a stem from which new tissues originate
- Cane
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A stem that has a relatively large pith (the central, strength-giving tissue of stem) and usually lives only one or two years
- Cane habit
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Shrub growth habit in which plants spread by sending up erect new branches, called canes, from their base
- Caneberries
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Fruits that grow on woody stems called canes, for example, raspberries, blackberries, and their hybrids
- Cataphylls
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The small, leathery, protective leaves that enclose and protect buds, found on rhizomes and are
- Cation exchange capacity
-
A measure of the total negative charges within the soil that adsorb plant nutrient cations
- Cell wall
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A rigid, structural layer outside the cell membrane in cells of plants, fungi, and some other organisms
- Centipedegrass
-
A coarse-textured stoloniferous warm-season grass that is adapted in southern Virginia from Martinsville to the coast. It is the lowest maintenance, highest density warm-season grass available.
- Cerci
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Typically paired appendages on the abdomen of many species of insect, typically with sensory function
- Chelates
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Chemical claws that help hold metal ions, such as iron, in solution, so that the plant can absorb them
- Chemical control
-
Use of pesticides to reduce pest populations. A pesticide is any substance that is used to prevent, destroy, repel, or mitigate any pest
- Chilling stress
-
Stress that occurs in plants sensitive to temperatures in the range of 68-32° F
- Chitin
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The primary component of the exoskeletons of arthropods such as crustaceans and insects
- Chloroplasts
-
Sites of photosynthesis within cells that contain chlorophylls and carotenoid pigments
- Chlorosis
-
Yellowing of normally green tissue
- Clays
-
The finest soil particles
- Climbing roses
-
Rose bushes that have flowers more than 2 inches across, borne on wood that is 2 or more years old. Canes are larger and sturdier than those of ramblers
- Clones
-
Groups of plants that are identical to their one parent and that can only be propagated asexually
- coconut coir
-
A pH-neutral, non-hydrophobic soil amendment that aerates and improves water retention of soil. Readily renewable and more environmentally friendly than peat moss
- Cold stratification
-
Process where seeds are exposed to a period of cold temperatures to break their dormancy cycle
- Columnar
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Column-like tree form
- Complete flower
-
A flower with a stamen, pistils, petals, and sepals
- Compound leaf
-
Leaf composed of several separate leaflets arising from the same petiole
- Conifers
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Gymnosperms, mostly evergreen but there are notable deciduous species, that have needle, scale-like, or awl-like foliage
- Conservation landscaping
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Landscape principles that apply best practices for conserving water, soil, and existing native plant communities.
- Contaminants
-
Undesirable substance not normally present, or an usually high concentration of a naturally-occurring substance, in water, soil, or other environmental medium. In more restricted usage, a substance in water that may be harmful to human health.
- Cork cambium
-
Falls outside the vascular cambium and is responsible for growth that replaces the epidermis in stems and roots.
- Cork spot
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Small dimples on the surface of apples, likely caused by lack of calcium availability in the developing fruit
- Corms
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A solid, swollen stem whose scales have been reduced to a dry, leaf-like covering. They have shapes similar to bulbs, but do not contain fleshy scales.
- Corolla
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The petals of a flower
- Cotyledons
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Modified leaves that are found on the embryonic plant and commonly serve as storage organs
- Crown
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A region of compressed stem tissue from which new shoots are produced
- Crowns
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Region of compressed stem tissue from which new shoots are produced, generally found near the surface of the soil
- Cultivar
-
Variety bred by people to have desired traits that are reproduced in each new generation (usually through asexual propagation)
- Cultural Control
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Modifying or disrupting the pest environment to make it less habitable for a pest
- Cuticle
-
Protective film covering the outermost layer of epidermis in leaves, some shoots and some other plant organs.
- Cuticle (insects)
-
The outer covering of the insect, includes most of the material of the exoskeleton
- Cutting
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A vegetative plant part which is severed from the parent plant in order to regenerate itself, thereby forming a whole new plant
- Day-length
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Duration of light received. For example, Poinsettia, kalanchoe, and Christmas cactus bud and flower only when day-length is short (11 hours of daylight or less).
- Day-neutral
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Plants that form flowers regardless of day length
- Deciduous trees
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Angiosperm trees that lose their leaves in the fall
- Dicots
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Flowering plants with seeds that contain a pair of embryonic leaves (cotyledons). Most of the broadleaf herbs, shrubs, and trees are dicots.
- Digger
-
Hand tool with a narrow curved or straight blade on the end of a long stick, also called an asparagus knife
- Dioecious
-
Plants with male and female reproductive organs on separate individuals
- Disease triangle
-
Represents three factors that interact to produce turfgrass disease: the disease causer, the susceptible grass, and a favorable environment
- Drainage
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(1) the natural movement of surface water over a land area to a river, lake or ocean (surface drainage), (2) removal of water from a soil using buried pipelines that are spaced regularly and perforated (subsurface drainage).
- Ecosystem
-
Biologically diverse communities, combined together with the other non-living (abiotic) elements of the surrounding environment, such as soil, water and sunlight that form a functional system of continuous energy exchange.
- Edge
-
Places where two habitat types come together.
- Endosperm
-
Built-in food storage supply in a seed
- Enlarged hypocotyl
-
Storage organ, the swollen portion of the stem below the cotyledon and above the roots
- Erosion
-
Detachment and transport of soil particles by water and wind. Sediment resulting from soil erosion represents the single largest source of nonpoint source pollution in the United States.
- Evapo-transpiration
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Water lost through stomata when they are open during the day
- Evaporation
-
Process by which a liquid is transformed to the gaseous state
- Extensive rejuvenation
-
Pruning technique that involves complete removal of the entire plant 6-10 inches above the ground
- Fastigiate
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Tree form that looks like a narrow oval
- Ferns
-
Class of herbaceous vascular plants that reproduce via spores
- Fertility
-
The ability of soil to sustain plant growth
- Fertilization
-
When materials for plant nutrition are supplied to the environment around the plant
- Fibrous root system
-
Root system in which the primary root ceases to elongate, leading to the development of numerous lateral roots which branch repeatedly and form the feeding root system of the plant
- Fine-leaf fescues
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Includes creeping red, hard, and chewing fescues. Exhibits the best tolerance of shade, drought, low-nitrogen, and acid soil
- Flooding
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Temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters or from the unusual and rapid accumulation of runoff.
- Floricane
-
Raspberry and blackberry plants that bear fruits on the second year cane
- Flower bud
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A but that contains partially preformed flower tissue
- Flower primordia
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The small buds at the end of stems from which flowers develop
- Freezing stress
-
Stress that occurs in plants sensitive to temperatures below the freezing point of water or 32°F
- Galls
-
Growth on the external tissues of a plant
- Genus
-
A group of somewhat closely related individuals (a group name) comprising one or more species
- Geophytes
-
Herbaceous plants with underground storage organs, rather than fibrous root systems
- Gradual rejuvenation
-
Pruning technique that removes growth gradually
- Groundwater
-
Water that fills voids, cracks, or other spaces between particles of clay, silt, sand, gravel or rock within a saturated zone or formation (aquifer) below the soil surface.
- Guard cells
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Epidermal cells located around a stoma that help regulate gas exchange by opening and closing
- Gymnosperms
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Seed-bearing vascular plants that produce exposed seeds, or ovules, which are usually borne in cones
- Habitat
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The area within an ecosystem where an animal is able to secure the food, water, cover and space it needs to survive and reproduce.
- Hand cultivators
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Digging hand tool with tines
- Hardening
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The process of altering the quality of plant growth to withstand the change in environmental conditions which occurs when plants are transferred from a greenhouse or home to the garden
- Hardiness
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A plant’s ability to withstand low winter temperatures and remain aesthetically pleasing
- Heading cuts
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Pruning cuts that reduce the height or width of a plant by cutting back lateral branches and removing terminal buds; made at nodal areas either above side branches or buds
- Hedge shears
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Shears with long, flat blades and relatively short handles, one for each hand
- Herbarium
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An organized and cataloged collection of such specimens, usually at a university or a museum.
- Hoe
-
Tool with a blade at a right angle to the handle. Examples may be pointed with a heart-shaped blade or have a narrow blade to slice through soil.
- Holometabolous
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An insect that undergoes complete metamorphosis with four distinct stages of development
- Host
-
A plant that another organism (such as an insect or virus) lives on
- Humus
-
The portion of organic matter that remains after most decomposition has taken place
- Hybrid
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A genetic cross of two different plants, usually from two different varieties of the same species
- Hypocotyl
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The portion of a seedling between the radicle and the first leaf-like structure
- Infection
-
To become established on/in the plant and initiate disease development
- Infiltration
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Process by which water (surface water, rainfall, or runoff) enters the soil.
- Infiltration rate
-
Quantity of water that enters the soil surface in a specified time interval. Often expressed as a volume per unit of soil surface per unit of time (in3 per in2 per hour). Soil surface wetness, soil texture, residue cover, precipitation rate, irrigation application, topography, and other factors control the infiltration rate.
- Inoculum
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Part of a pathogen that can cause infection
- Integrated pest management
-
An ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of appropriate control tactics. These tactics can be preventative, curative, or both and are often combined to provide the best possible results.
- Intergeneric hybrid
-
Cross between two genera (a very rare occurrence)
- Internode
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Section of the stem between two successive nodes
- Interspecific hybrid
-
A cross between different species of the same genus
- Intra-specific variation
-
Variation within a species
- Irrigation
-
Controlled application of water to land to supply plant water requirements not satisfied by rainfall
- Kentucky bluegrass
-
Turfgrass that provides lush, blue-green, fine-bladed lawns. Best suited to areas in and west of the Blue Ridge Mountains and north of Richmond.
- Landscape design
-
The process of planning and organizing the natural and man-made parts of the landscape into an aesthetic, functional, and environmentally sustainable space
- Lateral buds
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Buds borne on the sides of a stem
- Lateral root
-
Side or branch root that arises from another root. Also called a secondary root.
- Leaching
-
Removal of dissolved chemicals from soil caused by the movement of a liquid (like water) through the soil
- Leaf bud
-
Bud composed of a short stem with embryonic leaves
- Lesion
-
A well defined area of diseased or injured tissue, often dead spots or areas. Lesions are often a primary symptom.
- Light intensity
-
Influences the manufacture of plant food, stem length, leaf color, and flowering
- Light quality
-
The spectral distribution of light, or the number of different colored photons emitted by the light source (for example, blues, reds, greens)
- Loam
-
A textural class of soil that has moderate amounts of sand, silt, and clay
- Long-day
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Plants form flowers only when day lengths exceed 12 hours (short nights).
- Lopping shears
-
Long handled shears that are operated with both hands
- Macronutrients
-
Chemical elements required in large amounts for plant growth and development. These are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), and Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulfur (S).
- Mechanical/physical control
-
Using hands-on techniques or simple equipment/devices to reduce or prevent the spread of pest populations
- Meristem
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An area of cell division and growth Cells in the meristem can develop into all other tissues and organs found in plants.
- Microclimates
-
Zones of atypical high or low temperatures
- Micronutrients
-
Chemical elements required in small amounts for plant growth and development. These are: Iron (Fe), Zinc (Zn), Manganese (Mn), Boron (B), Copper (Cu), Molybdenum (Mo), Chlorine (Cl)
- Micropyle
-
A small pore located in a seed's seedcoat that allows water absorption and gas exchange
- Miniature roses
-
Rose bush 6 to 12 inches high with tiny blooms and foliage
- Monocots
-
Grass and grass-like flowering plants with seeds that typically contain only one embryonic leaf
- Monoecious
-
Plants with male and female reproductive organs on the same plant
- Mounding habit
-
Shrub growth habit in which plants often have soft, flexible stems, small leaves, and are often used in mass plantings
- Multiple fruits
-
Fruits derived from a tight cluster of separate, independent flowers borne on a single structure
- Nativars
-
Cultivars of native species
- Native plants
-
Plants that occur in the region in which they evolved.
- Net-veined
-
Leaf venation pattern in which veins branch from the main rib(s), then subdivide into finer veinlets which then unite in a complicated network
- Node
-
The part of the stem where one or more leaves are attached
- Nonpoint source pollution
-
Pollution originating from diffuse sources on the landscape. Examples include runoff from fields receiving manure applications, runoff from urban landscapes, or roadbed erosion in forestry. It has been estimated that NPS pollution accounts for more than one-half of the water pollution in the United States today.
- Nucleus
-
Organelle that contains the genetic information for the organism and controls the activities of the cell
- Open pollinated
-
Seed that is self or cross-pollinated by wind or insects and is produced by isolating plants from other plants of different varieties to produce seed that is "true to type"
- Opposite
-
Leaf arrangement where leaves are positioned across the stem from each other, two leaves at each node.
- Organic
-
Methods that involve growing and maintaining healthy plants without using synthetic (manmade) fertilizers, pesticides, hormones, and other materials
- Organic matter
-
Plant and animal material in varying stages of decomposition present in soil.
- Overhead watering
-
Watering system in which water is sprayed down on crops, directly wetting the crop surface
- Palmate
-
Leaf shape in which leaflets form and radiate from a single point of attachment
- Parallel-veined
-
Leaf venation pattern in which numerous veins that run essentially parallel to each other and are connected laterally by minute, straight veinlets
- Parent material
-
Bottom soil horizon, decomposed rock that has acquired some characteristics of the subsoil and retained some characteristics of the rock from which it weathered.
- Peat moss
-
Decomposed mosses and other living material found in peat bogs
- Peds
-
Peds are made up of mineral particles (clay, silt, sand) and organic matter; held together by the electrical charges on the surfaces of the minerals and organic matter
- Pendulous
-
Tree form in which branches hang down, also called weeping
- Perennial
-
Plants that live for many years. May be herbaceous or, if significant xylem develops in the stem and the top persists, may be classified as woody.
- Perennial ryegrass
-
A fine-medium textured grass that mixes well with Kentucky bluegrass
- Perfect flower
-
A flower with functional stamens and pistils
- Perlite
-
A sterile, porous soil amendment material produced by heating volcanic rock to approximately 1800ºF
- Pesticide
-
Any substance that is used to prevent, destroy, repel, or mitigate any pest. Can be synthetic (man-made), or natural products derived from plants, microorganisms, or inorganic elements
- Petals
-
Modified leaves, typically brightly colored, segments of a flower’s corolla
- Petiole
-
Stalk that supports the leaf blade
- Phenotypic
-
Visual appearance as a result of DNA expression
- Phloem
-
Transport tissue in vascular plants, transports the soluble organic compounds made during photosynthesis to the rest of the plant in a process called translocation
- Photosynthesis
-
Process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Generally involves the green pigment chlorophyll (in green plants) and generates oxygen as a byproduct.
- Pinnate
-
Leaf shape in which leaflets are attached along an extension of the petiole
- Pistil
-
The female part of the plant that consists of the stigma, style, and ovary
- Pistillate flowers
-
Flowers are those that possess a functional pistil(s), but lack stamens
- Plant community
-
The collection of plant populations found in that area
- Plant nutrition
-
The needs and uses of the basic chemical elements in the plant
- Plugs
-
Small squares/circles of sod grown in a tray
- Plumule
-
Embryonic shoot
- Point source pollution
-
Pollutant loads discharged at a specific location from pipes, outfalls, and conveyance channels. Point source discharges are generally regulated through the National Pollution Discharge Elimination System (NPDES) permitting procedures established by the EPA. Point sources can also include pollutant loads contributed by tributaries to the main receiving stream or river.
- Pole pruners
-
Shears with a hooked blade above and a cutting blade beneath. The cutter is on a pole and is operated by a cord or chain pulled downward
- Pollutant
-
Any substance of such character and in such quantities that when it reaches a body of water the effect is to degrade the receiving water perhaps to a point rendering it unfit for some specified designated use
- Pollution
-
Alteration of the physical, biological, chemical, and radiological integrity of water due to human activities ‚ any unwanted contaminating property that renders a water supply unfit for its designated use.
- Precipitation
-
Rain, sleet, snow, or hail that falls to the earth as the result of water vapor condensing in the atmosphere.
- Precocity
-
In grafting, the ability of rootstocks to induce fruitfulness. Precocity is measured in apple rootstocks by observing the length of time from planting to when the cultivar produces flowers.
- Pregermination
-
Sprouting the seeds before they are planted in pots (or in the garden)
- Primocane
-
Raspberry and blackberry plants that bear fruits on the first year cane (shoot) which are ready for harvest in late summer
- Provenance
-
Source of plant material
- Radicle
-
Primary root, first organ to appear when a seed germinates
- Rain garden
-
A shallow landscaped depression that filters polluted stormwater before it evaporates, evapo-transpires through the plants, or percolates through the soil into the groundwater.
- Rake
-
Tool with a long handle and crossbar with a toothed comb, helpful in spreading mulches and smoothing seedbeds
- Rambler roses
-
Rose bushes that have clusters of flowers, each usually less than 2 inches across
- Relative humidity
-
The ratio of water vapor in the air to the amount of water the air could hold at a given temperature and pressure, expressed as a percent
- Respiration
-
Process by which plants use the sugars produced during photosynthesis (plus oxygen) to produce energy
- Rhizomes
-
Specialized stem that grows underground and sends out roots and shoots from nodes
- Rhythm
-
Design principle of even repetition, and it directs the eye in the landscape through continuity and flow
- Riparian
-
Pertaining to the banks of a river, stream, or other typically, flowing body of water as well as to plant and animal communities along such bodies of water. This term is also commonly used for other bodies of water, e.g., ponds, lakes.
- Root cap
-
Outermost tip of the root, consists of cells that are sloughed off as the root grows through the soil
- Root hairs
-
Projects of root epidermal cells, important in absorption of nutrients, plant anchorage, and more
- Rootstock
-
In grafting, the piece of shoot that provides the new plant’s root system and sometimes the lower part of the stem, the lower portion of the graft
- Rose standard
-
Tree rose, a Hybrid Tea, Grandiflora, or Floribunda budded at the top of a tall trunk
- Rosulate
-
A circular arrangement of leaves, usually near the soil (for example, dandelion)
- Rotary tiller
-
Power toll with a series of rotating tines used for working soil several inches deep
- Runner
-
A specialized stem that grows on the soil surface and forms a new plant at one or more of its nodes. A type of stolon.
- Runoff
-
Part of rainfall or snowmelt that does not infiltrate the soil but flows over the land surface toward a surface drain, eventually making its way to a stream, river, lake or an ocean. It can carry pollutants into receiving waters. Also known as stormwater.
- Rushes
-
Members of the Juncaceae family of flowering plants; distinguishable from grasses and sedges by their round (and frequently unbranched) stems filled with pith (not hollow)
- Sand
-
Coarser mineral particles of the soil
- Scale
-
Design principle that refers to the size relationship or proportion between different parts of a landscape. This could be between buildings and plants, plants and plants, or plants and people
- Scarification
-
Breaking, scratching, or softening the seed coat so that water can enter and begin the germination process
- Scion
-
In grafting, the piece of shoot with dormant buds that will produce the stem and branches on the upper portion of the graft
- Sclerites
-
Hardened plates joined together forming the hard surface of insects
- Secondary growth
-
Growth in lateral meristems that causes increase in girth
- Sedges
-
Members of the Cyperaceae family of grass-like monocotyledonous flowering plants; distinguishable from rushes and grasses by their triangular stems
- Sediment
-
In the context of water quality, soil particles, sand, and minerals dislodged from the land and deposited into aquatic systems as a result of erosion.
- Sepals
-
Small, green, leaf-like structures on the base of the flower that protect the flower bud
- Sexual propagation
-
Involves the union of the sperm (male) with the egg (female) to produce a seed
- Shoot
-
A young stem with leaves present
- Short-day
-
Plants that form their flowers only when the day length is less than about 12 hours in duration.
- Shovel
-
Tool used for digging and lifting loose soil or other materials
- Shrubs
-
Perennial woody plants that have one or several main stems, and usually are less than 12 feet tall at maturity.
- Signs
-
Structures or products of the pathogen itself on a host plant, for example, mold, fungal fruiting bodies, or bacterial slime/ooze
- Silt
-
Relatively fine soil particles that feel smooth and floury. When wet, silt feels smooth but is not slick or sticky.
- Simple fruits
-
Fruits that develop from a single ovary
- Simple leaves
-
Leaves with a leaf blade that is a single continuous unit
- Sod
-
Upper layer of soil with grass growing, often harvested and rolled
- Soluble salts
-
Minerals dissolved in water that can accumulate in potted plants
- Spading fork
-
Digging tool with strong, flat tines that is ideal for breaking and turning heavy soils and for loosening subsoil layers when double digging a bed
- Species
-
A group of individuals that can be characterized by a set of identifiable characteristics that distinguishes them from other types
- Species diversity
-
The use of many varied taxa (family, genus, species) within an “area”, where an area may range from a residential site to municipal or larger sites
- Specific epithet
-
The second word of the Latin binomial that usually functions as an adjective (or sometimes named after an individual) and indicates or describes the member of the genus
- Spines
-
Specialized modified leaves that protect the plant
- Sprigs
-
The stems from shredded sod. Sprigs should include leaves, a stolon, and roots
- St. Augustinegrass
-
A coarse-textured stoloniferous warm-season grass that has the best shade tolerance of warm-season grasses.
- Stamen
-
The male reproductive organ. It consists of a pollen sac (anther) and a long, supporting filament
- Staminate flowers
-
Flowers that contain stamens, but no pistils
- Stolon
-
Horizontal stem that is fleshy or semi-woody and lies along the top of the ground
- Stomata
-
Openings in leaves that allow passage of water and gasses into and out of the leaf. Singular: stoma
- Storage leaves
-
Serve as food storage organs, found on bulbous plants and succulents
- Stress
-
Any change in environmental conditions that adversely affects survival, growth, development and yield in plants
- Stubble mulch
-
A stubble of crop residue left in place for winter
- Subsoil
-
Usually finer and firmer than the surface soil. Organic matter content of the subsoil is usually much lower than that of the surface layer.
- Subspecies
-
A grouping within a species used to describe geographically isolated variants
- Suckers
-
Vigorous shoots growing from the trunk or roots
- Surface horizon
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Contains more organic matter than the other soil layers. Organic matter gives a gray, dark-brown, or black color to the surface horizon
- Symptoms
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Physical expressions of disease in the host tissue, e.g., changes in color, appearance, integrity, etc.
- Tall fescue
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A fine to moderate coarse-textured turfgrass which is tolerant of a wide range of soil types and climatic conditions
- Taproot
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Formed when the primary root continues to elongate downward into the soil and becomes the central and most important feature of the root system, with a somewhat limited amount of secondary branching.
- Taxon
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Any taxonomic group/category
- Temperate
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Perennials native to moderate temperature regions without extreme cold or a tropical climate
- Terminal bud
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Buds located at the apex of a stem
- Terminal buds
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Buds located at the apex of a stem
- Thatch
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An organic mat of stems that forms between the mineral soil and the turfgrass canopy
- Thermoperiod
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The daily range of temperatures a plant is exposed to
- Thinning cuts
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Also called reduction cuts, pruning cuts that remove branches at their points of origin or attachment
- Topping cuts
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Height-reducing pruning cuts made indiscriminately in internode areas
- Transpiration
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Process by which a plant loses water, primarily from leaf stomata.
- Tree-like shrubs
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Shrubs that have woodier, finely divided branches and can be pruned as a single-trunk or multi-stemmed trees
- Trees
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Perennial woody plants, usually with one main trunk and usually more than 12 feet tall at maturity
- Trowel
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A small hand-tool for digging
- Trunk
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A main stem of a woody plant
- Tuber
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Enlarged portion of an underground stem. The tuber, like other stems, has nodes that produce buds.
- Tuberous root
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Modified lateral roots that are enlarged to function as an underground storage organ. Found in dahlia and sweet potato.
- Tuberous roots
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Underground storage organ
- Tuberous stem
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Shortened, flattened, enlarged, and underground stem. Examples are tuberous begonia and cyclamen.
- Turbidity
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Measure of the cloudiness or opaqueness of the water expressed in nephelometric turbidity units (ntu). The turbidity is influenced by the amount and nature of suspended organic and inorganic material in water. Typically, higher concentrations of the suspended material equal greater turbidity. The source of turbidity could be sediment (fine sand, silt, and clay), organic material, particles of iron and manganese or other metal oxides, rust from corroding piping, algae, carbonate precipitates, etc.
- Turgor
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Turgidity (swelling) and resulting rigidity of plant cells or tissues, typically from the absorption of fluid
- Twig
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A stem that is less than one year old and has no leaves since it is still in the winter-dormant stage
- Unity
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Design principle created by repetition of shapes, lines or colors, the grouping or arranging different parts of the design to appear as a single unit
- Vacuole
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A large liquid-filled cavity within a cell
- Variety
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A subpopulation of a species that has a distinctive trait that distinguishes it from the rest of the species and occurs in nature
- Vascular bundle
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Part of the transport system in vascular plants that includes the xylem, phloem, and other tissues
- Vascular cambium
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The main growing tissue of stems and roots in most plants. It produces the secondary xylem and secondary phloem.
- Vegetative bud
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A bud that contains partially preformed leaf and stem tissue
- Vermicompost
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Compost made by worms as they digest plant material
- Vermiculite
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A sterile, lightweight, mica product used as a soil amendment
- Vernalize
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Cool the plant in order to encourage flowering
- Verticutting
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Vertical mowing to remove thatch buildup
- Vine
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A plant that develops long, trailing stems that grow along the ground unless they are supported by another plant or structure
- Voucher specimen
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A specimen of a species that depicts clearly its most important physical characteristics and structures.
- Water table
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The depth at which soils are fully saturated with water, the upper surface of an unconfined aquifer.
- Water-holding capacity
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The amount of water that a soil can hold for crop use
- Watershed
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Area that drains or contributes water to a particular point, stream, river, lake or ocean. Watersheds are also referred to as basins. Watersheds range in size from a few acres for a small stream basin, to large areas of the country like the Chesapeake Bay Basin that includes parts of six states.
- Watersprouts
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Vigorous, usually-upright shoots that grow from the trunk or branches
- Well
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Deep hole or shaft sunk into the earth to obtain water groundwater.
- Wetland
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Transitional lands between terrestrial and aquatic systems where the water table is usually at or near the surface, or the land is covered by shallow water. Wetlands are those areas where water saturation is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the surrounding environment.
- Whorled
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Leaf arrangement where leaves are arranged in circles along the stem.
- Wide row planting
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Planting in such closely-spaced bands rather than in rows of individual plants
- Windbreaks
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Plantings of trees and shrubs placed strategically to slow winds
- Witch’s broom
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deformity in a woody plant where a mass of shoots grows from a single point
- Woody plants
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Perennials (life span ranges from decades to centuries, or in some cases millennia) in which the shoot (above ground portion of the plant) persists during plant dormancy (usually late-autumn to early-spring)
- Xylem
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Transport tissue in vascular plants, transports water from roots to stems and leaves (also transports nutrients)
- Zoysiagrass
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A warm-season grass of fine to medium texture that turns brown with the first hard frost in the fall and greens up about mid-May.