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Outdoor and Landscaping Glossary


Aeration, Aerator – The process of changing soil so more oxygen can enter, usually by using an aerator, which is a machine that pulls cores from the ground. In Portland we will normally be discussing aerating a lawn that is having trouble taking in soil and water. When should you aerate a lawn?

Aggregate – Fractured or rounded stone used as a footing, sub-base, or decorative surface. The most common aggregates in Portland landscapes are 1/4”- gravel and pea gravel. Learn more about types of aggregates here.

Annual – A plant that flowers and dies in one season (think pansies). You would normally purchase an annual just as it begins to flower and then remove it once it is done, or perhaps as seeds. We very rarely include annuals in our landscape designs, preferring perennials.

Arbor – A garden structure generally used to support climbing plants or vines. They can be part of a fence, gate, or free standing.

Arborist – Basically a tree doctor that is trained in the care and maintenance of trees. The City of Portland has a good guide to working with an arborist, and these are the “tree guys” we trust.

Accent Plants – Plants that provide interest and generally stand out in the landscape due to their color, texture, and/or blooms. They do not set the structure of the garden and primarily serve aesthetic goals. My favorite accent plants right now are Quicksilver Hebe and Coneflower.

Access –  A way to approach an area or garden feature. The concept of “access” can be practical: providing access for maintenance. Or it can be a matter of aesthetics: making access welcoming so you are drawn toward a garden destination.

Aesthetics – Very subjective, this is the perception of beauty or attractiveness of a garden space or design. No matter how practical a garden needs to be it also needs to meet a certain threshold of aesthetics. “Aesthetic” may also be used to describe a chosen style or look for the landscape.

Allee – A walkway bordered with trees, bamboo, or hedges. Generally a formal feature meant to emphasize the approach to a main entrance feature.

Amend – Adding beneficial organic material to your garden’s native soil to improve it for plants. Usually this is done by mixing in some compost as we install plants.



Backfill – Gravel or dirt used to fill behind a retaining wall or other landscape feature.

Backflow Prevention Device – Valve required by the City of PDX to prevent water in your irrigation system from being siphoned back into the water supply.

Balance – A design concept, where elements in the landscape are in “balance” with one another. The size, orientation, and perceived mass of elements all play a role. This is highly subjective.

Balled and burlapped – Field dug tree with the root ball wrapped in burlap. Often abbreviated to “B&B” in the trade.

Basalt – (as it relates to landscaping in Portland) The most common type of landscape and masonry stone. Boulders from the Columbia River Gorge and other local quarries are usually basalt. The most common basalt is gray, but black basalt and basalt with brown tones is also available.

Basin –  An enclosed area of water. When discussing water features the basin may be the water receptacle below ground or the pot or vessel that water spills out of.

Bubbler – A style of water feature with a large drilled stone usually serving as the centerpiece.

Boulder – Large stone. In general a stone over 125 lbs would qualify as a boulder. More about the proper way to set boulders is here.



Cascade – Where water in a stream or vessel hits a point of vertical drop. The height and width of a cascade are major factors in the amount of noise generated by a water feature.

Catch basin – A below grade vessel for collecting surface water and then directing it into a drain line or dry well. Also, an area where water pools before falling over the next cascade.

Clump – Group of trees, shrubs, bamboo, or ornamental grass planted together to form a grouping.

CompostDecomposed garden or food material, used in planting beds to amend from above and hold moisture where it is needed.

Concept Plan – During the landscape design process, this is a basic drawing or plan containing the key details of the garden plan, without adding excessive details or full plantings so the basic footprint of key elements can be understood. Examples of plans from Ross NW Watergardens’ designer are here.

Conifer – Tree that bears cones and needle-like or scale-like leaves that are typically evergreen. Pine, cedar, hemlock, redwood, fir, cypress, juniper, spruce, and arborvitae are common conifers in the PNW.

Contour –  Purposeful change in ground elevations or grade. These may take the form of a mound, swale, or combination of the two.

Contrast – Differences in tone, texture, mass, or color between landscape design elements. Plant combinations or pairings often highlight these differences so that each plant can shine.

Course – A horizontal row or tier of stone, paver, or wood in a wall , patio, or landscape screen.

Courtyard garden – A garden mostly or completely surrounded by walls or buildings, perhaps at the entry to a building or meant to viewed from key windows.

Curbing – A border or edging using poured concrete or natural stone.



Deciduous – A tree or bush (shrub) that loses its leaves in winter. In the PNW there are semi-deciduous or semi-evergreen plants that may lose their leaves depending on how cold the winter is. Abelia and some hebe are good examples.

Deck – A flat gathering space, made of wood or composite material (made to look like wood), typically adjacent or attached to a structure. A deck usually sits above grade, a patio would generally be at grade.

Decking –  Materials the surface of a deck is made out of. Cedar, ipe, juniper, and composite are the most common decking materials in Portland. Some excellent decking contractors are recommended here.

Decorative rock – Rocks chosen for their color or texture and used as a ground cover, walking surface, or focal point. Black beach pebbles, pea gravel, and granite are the most common choices in Portland landscape designs. A wide selection of decorative rock can be found at Smith Rock, Inc and Oregon Decorative Rock.

Decomposed Granite – Granite that is weathered to the point that it is a very fine aggregate. This is a natural process, and the result can be used for paths and patios. Decomposed granite is often referred to as DG. It is especially useful in modern landscapes.

Design Elements – Key landscape features being proposed in a landscape design plan. Water features, paths, patios, decks, boulders, plantings, screens, fences, and contouring are just some of the common design elements.

Design Objectives – Goals that the client has for the new landscape. These goals guide the design process, not the designer’s style or preferences. Common design objectives in Portland are low maintenance, drought tolerant, and animal friendly.

Dethatch – Process for removing or thinning the dead lower level of a mature lawn. Thatch is grass that has died and collected below the green blades. Some thatch is normal and healthy. However, over time this layer can get very thick and make it difficult for water, sun, and nutrients to get to portions of the turf.

Drainage – The process of collecting and controlling the flow of water on a property. This can be done with grading, French drains, dry wells, permeable surfaces, sump pump, rain gardens, and more. Often multiple methods are required since Portland gets so much rain. Properties at the bottom of hills, with natural springs, or full of heavy clay have the most drainage problems.

Drip irrigation – A slow feeding irrigation system that utilizes flexible tubing and emitters to send a precise amount of water to each plant. This is the most efficient method of irrigating plants.

Drought Tolerance – The ability of a plant to survive without much summer water. There are many plants that are “drought tolerant” but most will be happier with at least some summer water, and all will need some water the first couple of summers.

Dry Garden – A garden feature where water is represented by an aggregate stone product, usually a gravel or granite. These are most commonly found in modern and Japanese garden design.

Dry-laid – A stone or flagstone patio, path, or walkway built without a concrete base. The base would be compacted gravel and the joints would be an aggregate or walkable ground cover. Dry laid stone work is more rustic and will become somewhat uneven over time.

Dry-stacked – A stone retaining or free standing wall built without the use of mortar. A highly skilled mason is required for a dry stack stone wall. Most walls in Portland are not dry stacked, even if they appear to be.

Dry Well – An underground structure that collect water and allows it to slow percolate into the soil around it. Dry wells can be installed in the landscape so that roof or rainwater is not sent into Portland’s water treatment system.



Ecological: Landscape design that is compatible with a sites’ environment in both appearance and sustainability without negative impacts on the environment.

Edging: Edging in the landscape is a line of demarcation that creates visual interest in the garden by separating one segment from another segment. This can be aesthetic or functional, keeping one element (such as pea gravel) from getting mixed into another (like bark dust).

Enclosure: In a landscape design, to fence or wall an area in. Areas can also have a feeling of “enclosure” provided by trees, other plantings, fences, or screens.

Entry GardenThe landscape near the entry to a building.

Espalier: A tree, shrub, or vine, trained to grow on a wall or fence into a specific pattern. Especially useful for fruit trees, making it easy to harvest the fruit and containing mess.

Evergreen: A plant whose leaves or needles are green year-round.

ExoticA plant that is not native to the location where it will be planted. Not all “exotics” are invasive or harmful, and many can be well behaved or drought tolerant.



Fernery: A mass planting of ferns.

Fescue: Thicker bladed turf grass that spread via rhizomes.

Final grade: The level of soil on your property before bark dust or compost is spread.

Fixture (Low Voltage Lighting): The lighting elements of a landscape lighting system. Primary fixtures types are spotlights, path lights, well lights, and underwater lights.

Flagstone: Generic term used to describe natural flat stones of different shapes and colors used to create walkways, patios, and walls. Flagstone is usually larger than stepping stones.

Float valve: A valve that will automatically refill your water feature when the waterfalls below a certain level. These are usually connected to your irrigation system.

Flow control valve: Usually a ball or gate valve that gives you control over the flow of water coming from your pump to your water feature.

Focal Point: The element in a landscape design or area in a landscape that is meant to be most prominent. The focal point can be a plant, boulder, statuary, gathering space, or other landscape feature.

Formal: A style of gardens or garden elements that stress straight lines, right angles and circles.

Foundation PlantingsBushes or shrubs located in beds near the foundation of a home or other structure.

French Drain: A trench filled with 2” round rock containing a perforated pipe that collects and redirects surface water and groundwater away from an area, many times to a dry well.

FunctionThe purpose, reason, or action that an area is being landscaped for. Stairs function, for example, to allow foot traffic up and down a slope.



Garden: Space for growing plants for viewing, eating, or physical activity.

Gazebo: A roofed building used over an outdoor gathering space.

Germination: The sprouting of a seed, perhaps referring to a lawn that is being grown from seed.

Grading: Changing the level of soil for better drainage or to create interest or function.

Gravel: Rock product, either rounded or fractured, that is relatively small- usually 1” or less.

GroundcoverLow plants that are allowed or encouraged to spread over an area.



Hardscape: Can refer to any “hard” garden elements including statuary or boulders but most commonly is used to refer to paths, patios, and walls.

Head: Height difference between the level of water in a pond (or the level of the pump if it sits outside the pond) and the upper outlet of water which impacts the performance of the water pump in gph (gallons per hour).

HedgeDense shrubs or trees that form a fence, screen, or boundary.

HerbaceousPlants with non-woody stems.

Herbicide: A chemical used to control weeds.

Horizontal Slats: Fence boards that run horizontally, often used in modern or Japanese-inspired landscape designs.



Imaginary Lines: Lines that define spaces within a landscape concept. These often extend from corners or key features of an existing structure. Proper use of imaginary lines can help the landscape feel connected to the home and other elements.

Informal: The opposite of formal in the landscape. A more relaxed garden dominated by curved rather than straight bed lines and a less rigid structure. Traditional PNW landscapes are informal.

Invasive Plant: A plant that spreads more than desired, or into habitats where it does damage. Portland has a list of invasive plants that should not be installed in landscapes because they can spread to forests or waterways and be difficult to control.

Irrigation: Watering plants and lawn, usually with an irrigation or sprinkler system. Smart irrigation controller reviews and recommendations here.

Irrigation /Sprinkler Plan: 2-D rendering of the proposed irrigation system. Can include head placements and coverage, pipe sizing, GPM specs, and materials needed to install this system. An irrigation plan is usually unnecessary for residential properties but is common for commercial projects.



Landscape Architect: Licensed professional who designs landscapes, schooled in engineering and architecture as well as in horticulture.

Landscape Design: The art or practice of planning (designing) changes to landscaped areas, either for aesthetic or practical purposes.

Landscape Designer: The professional who plans and develops landscape projects, usually at a residential or small commercial level with the major design impetus on plantings. Landscape designers typically have less schooling than Landscape Architects and are not licensed.

Landscape Plan: A completed landscape design, detailing all elements for the new landscape. This usually takes the form of a drawing on paper.

Landscape Fabric: Textile used to suppress weeds, keep aggregate from sinking into mud, and to protect French drains from silt.

Lime: Calcium material used to raise the pH in soil, which will make it less hospitable to moss.

Liner: A watertight HDPE material used underneath ponds, streams, and waterfalls in water features.



Mass Plantings: Using many plantings of the same variety to fill in an area in the landscape. This can lower maintenance and water use in the garden.

MaterialsList: A compiled list of all materials needed to install the landscape design.

Microclimate: Variations in temperature and growing conditions based on in elevation, sunlight, drainage, or wind as seen in your own yard.

Minimalism: Using the smallest number of plants, plant varieties, hardscape materials and other elements needed to accomplish the goal for the landscape design. This aesthetic is usually associated with modern and low maintenance landscape design.

Mixed Border: A flowerbed with a mix of different plants such as flowering perennials and shrubs.

Modernism: Modern landscape design is characterized by clean lines, clear borders between elements, mass plantings, and minimalism.

Moongate: This is a circular aperture in a wall or fence, most often seen in Chinese or Japanese gardens.

Mortar: A mix of cement, sand, and water that is used in stone masonry for setting stones and joints.

Mulch: A layer of compost or bark dust applied at the base of a plant.

Mossery: A mass planting of moss.



Native Plant: A plant that was present in a geographic location before people started changing the landscape.



Orchard: A place for growing fruit trees, can be within a larger landscape.

Orientation: How the garden or a garden element is arranged in relationship to an existing or new feature or to a direction.

Organic Lawn Care: Maintaining a lawn without the use of chemical herbicides, pesticides, or fertilizers.

Ornamental grasses: Grasses that are not mowed but grown in landscapes as perennials.



Patio: This is a partially open-sided relaxation or recreation area that adjoins a dwelling, used for entertaining, outdoor dining and simply enjoying the outdoor environment.

Pavers: Precast concrete pieces that are used to create patios and walkways.

Pea Gravel: Small round gravel.

Perennial: Plants that provide seasonal interest and then die back in the winter. Annuals do not come back the following season, but perennials do.

Perennial Rye: Cold season grass that is the most common turfgrass in Portland, OR, and the rest of the PNW.

PergolaAn open-roofed structure over a patio or other landscape feature.

Pesticide: A chemical used to control insects.

Planter: An ornamental container for growing plants.

Pondless: A water feature with no true pond, the water basin is below grade and often hidden by round rock.

Privacy Screen: Fences, trellises, or shrubs used to block the view of a certain area or view.

Pruning: Cutting parts of a plant off to control size, health and appearance.

PVC Pipe: Kind of pipe used in most irrigation systems.



Quarter Minus (1/4-): Basalt aggregate ranging in size from 1/4” down to dust. The most common landscape gravel in the PNW.



Rain Garden: Area of the landscape designed to handle rainwater until it can soak into the ground.

Rain Chain: A chain that controls water as it travels from a roof gutter to the ground.

Raised Bed (aka Raised Garden Bed): Garden structure that creates a planting area that is contained and higher than the surrounding grade.

Rendering (3D): A 3 dimensional perspective of a landscape design.

Retaining Wall: Structure made of wood, concrete, paving stones, bricks or other materials for stabilizing slopes and preventing excessive erosion.

RillNarrow watercourse.

Rock Garden: Creating a garden feature consisting primarily of stones with plantings that complement and can thrive in the rocky environment.

Rotor: Sprinkler head style that rotates a stream of water across an area.

Rotary Nozzle: A nozzle that goes on a head and creates streams of water that rotate across an area.



Scale: On a landscape design the scale indicates how space on the plan relates to space in the actual garden. Also refers to the relationship between sizes of specific elements in the landscape.

Screening Plantings: Trees or shrubs used to provide privacy, block a view, or as a natural boundary or barrier.

Setback: Space around your home or along property lines where there are restrictions on what can be installed or built.

Shocking: Damage sometimes manifest after a plant is transplanted.

Shrubs: Low woody plants, usually with multiple shoots or stems emanating from their bases.

SiteThe space of ground to receive landscaped improvements.

Site Analysis: The act of ascertaining features inherent to a site that must be accounted for in the landscape design.

Sketch: A rough drawing showing key elements of a landscape plan.

Sod: Strips of grass that have been cut out of field and rolled up. They can then be unrolled and installed as a lawn.

Sod cutter: A machine used to cut grass out.

Specimen: This plant is grown by itself in a lawn or garden for its ornamental effect, rather than massed with other bedding or edging plants. Will usually be a focal point.

Sprinkler System: Underground network of controllers, valves, pipes, and heads that combine to water the landscape.

Steel edging: Most common landscape edging in Portland, usually a 1/8” by 4” by 20’ length.

Stepping Stones: Flat stones or concrete pavers set with large gaps to accommodate a natural stride, creating a rustic path.



Timer (Irrigation): Controller for a sprinkler system.

Transformer (Low Voltage Lighting): Converts 120V to 12V for powering a landscape lighting system.

Transplant: Moving a plant from one location to another.

TreeA woody perennial plant having a single usually elongate main stem generally with few or no branches on its lower part. (Merriam-Webster)

Tsukubai: Small water feature derived from the concept of a Japanese hand washing station.



Variegation: A pattern of leaves that contains either white or yellow markings.



Wall Rock: Quarried basalt stones that are 5-75 lbs each.

Water Feature: Landscape element that features circulating water.

Weed: Any plant that is unwanted or considered to be a nuisance.



Xeriscaping – A way of landscaping using very little, or no water with drought-tolerant plants and more hardscaping.