Glossary of interior landscaping terminology

Included here are definitions of the more commonly found abbreviations and words used in the interior landscape industry.

Common abbreviations

ACOP Approved Code Of Practice

AIA American Institute of Architects
ALCA American Landscape Contractors’ Association
BALI British Association of Landscape Industries
BASIS British Agrochemical Standards Inspection Scheme
BPCA British Pest Control Association
BS British Standard
BSI British Standards Institute
CCW Countryside Council for Wales (formerly NCC)
CITES Convention on International Trade in Endangered Species
COPR Control of Pesticides Regulations
COSHH Control of Substances Hazardous to Health Regulations

CPD Continuing Professional Development

DEFRA (UK) Department of the Environment, Food and Rural Affairs

E-FIG European Federation of Interior-landscaping Groups
EHO Environmental Health Officer
EN English Nature (formerly NCC)
FEPA Food and Environment Protection Act
GRP Glass Reinforced Plastic (often known as fibreglass)
HASWA Health And Safety At Work Act
HSE Health and Safety Executive
ILG Interior Landscape Group (of BALI (q.v.))
ISO International Standards Organisation
LD50 Lethal Dose 50%
LECA Light Expanded Clay Aggregate
MEL Maximum Exposure Limit
MEWP Mobile Elevating Work Platform
mg/kg (or mg.kg-1) Milligrammes per Kilogramme
NCC Nature Conservancy Council (see CCW, EN & SNH)
NPK Nitrogen, Phosphorus, Potassium
NPTC National Proficiency Test Certificate
OES Occupational Exposure Standard
PPE Personal Protective Equipment
ppm Parts Per Million
%RH Percent Relative Humidity

RIBA Royal Institute of British Architects
RIDDOR Reporting of Injuries, Diseases and Dangerous Occurrences Regulations
RoSPA Royal Society for the Prevention of Accidents
RPE Respiratory Protective Equipment
SBS Sick Building Syndrome
SDS Safety Data Sheet
SNH Scottish Natural Heritage (formerly NCC)
sp Species (singular)
spp Species (plural)
SWL Safe Working Load
ULV Ultra-Low Volume


Common Words

A
ABSCISSION The controlled shedding of part of a plant e.g. separation of leaves from the stem.
ABSCISSION LAYER A thin plate of cells which forms at the point of abscission (q.v.).
ACID Refers to a material, e.g. soil, water, with a pH level below 7.0.
ACCIDENT An unforeseen occurrence which results in injury to persons or damage to property.
ACUMINATE Tapering to a slender point.
ACTIVE INGREDIENT A chemical ingredient from which preparations are formulated, e.g. Deltamethrin in Deleet.
ADVENTITIOUS Plant growth occurring in an unusual position e.g. aerial roots (q.v.).
AERIAL ROOT A root that arises above soil level e.g. as in Monstera deliciosa.
AEROBIC Living or functioning only in the presence of air.
AIR FILLED POROSITY The proportion of the volume of a growing medium that contains air after it has been saturated with water and allowed to drain.
ALKALINE Refers to a material, e.g. soil, water, with a pH level above 7.0.
ALTERNATE A form of leaf arrangement in which there is one leaf at each node (q.v.), giving a staggered formation up the plant stem.
ANAEROBIC Living or functioning in the absence of free oxygen.
ANNUAL RING The growth produced by the stem of a woody plant in a single year. In transverse section, it is often possible to distinguish the separate “rings”, providing an easy method of ageing the plant.
ANNUAL A plant that germinates, blooms then dies within a single year.
APICAL At the tip of a branch or stem.
ARISTATE Bearing thistles, often to the extent of appearing bearded.
ASYMMETRICAL LEAF A lop-sided leaf with one half larger than the other.
AURICULATE Having ear-shaped lobes at the base of the leaf.
ANTHER The male part of the flower that produces pollen.
AUTOTROPHIC The ability to produce complex organic substances from simple inorganic compounds e.g. as in most plants.
AXIL The angle between the upper surface of a leaf or leaf stalk and the stem that carries it.
AXILLARY BUD New shoots or flowers growing from the axil (q.v.).

B
BALI British Association of Landscape Industries.
BARK The protective layer of plant tissue that grows around the cambium (q.v.). Used as a decorative mulch (q.v.) when chipped or as a compost additive when partially decomposed.
BASIDIOMYCETES A group of higher fungi that includes most of the wood-rotting species. Can cause damage to the roots of containerised plants, especially if over-watered and bark mulch gets mixed into the soil.
BIANNUAL Growing twice a year.
BIENNIAL A plant which germinates one year and flowers, produces seed and dies the next, thereby completing a two-year life cycle.
BIOLOGICAL CONTROL AGENTS Parasites, predators, viruses, bacteria and fungi. Widely used in horticulture to control pests.
BIP Abbreviated term used for Philodendron bipinnatifidum.
BIPINNATE Describing a compound leaf with two rows of leaflets (pinnae) which are themselves divided into even smaller segments.
BLADE The main expanded part of a leaf as distinct from its stalk. Also called the lamina (q.v.).
BLOOM A delicate powdery or waxy coating found on some leaves and fruits e.g. the silvery “frosting” on Aechmea fasciata leaves.
BONSAI The art of dwarfing trees by root restriction and pruning.
BRACT A modified leaf, often part of a flower, which may be either leaf-like or petal-like, and is sometimes highly coloured e.g. Poinsettia.
BREAK The side shoot that forms after removal of the growing point.
BUD A shoot in embryonic form containing a miniature stem, leaf or flower.
BULK DENSITY The dry mass per unit volume of moist growing medium.

C
CAMBIUM The area of plant tissue, usually just below the bark, that is responsible for producing new growth.
CAMPANULATE Bell-shaped.
CAPILLARY ACTION The natural upward movement of water and other liquids in confined spaces e.g. plant cells, spaces between soil particles.
CAPITULUM A cluster of tiny florets (q.v.) that looks like a single bloom e.g. members of the daisy family.
CARBON CYCLE The circulation of carbon between living organisations and the environment.
CARNIVOROUS PLANT A plant that is adapted to obtain food by digesting insects and other small animals, in addition to photosynthesis. Also called “insectivorous”.
CAROTENOID A yellow, orange or brown pigment found in leaves, fruit and flowers. Contributes to the autumn colours in deciduous leaves.
CELLULOSE A carbohydrate forming the main constituent of plant-cell walls.
CHLOROSIS Abnormal yellowing or blanching of leaves, usually through lack of chlorophyll or essential minerals.
CHLOROPHYLL A pigment in the green parts of plants involved in the light reactions of photosynthesis (q.v.).
CHLOROPLAST The chlorophyll-containing structures within the green parts of a plant.
CILIATE Describing leaves, bracts or petals that are fringed with fine hairs.
CLADODE A flattened stem resembling and performing the functions of a leaf.
CLASS The group of plants on the next rank below a division or phylum (q.v.).
CLAVATE Club-shaped.
COIR Fibre derived from the outer husk of coconuts which, when partially decomposed, is sometimes used as an alternative to peat in growing media.
COMPOST Strictly speaking, manure of organic origin but more commonly used in the landscape industry to refer to the growing medium.
COMPOUND LEAF A leaf made up of two or more leaflets (q.v.) attached to the leaf stalk.
CONCENTRATE A formulation containing the active ingredient at a higher concentration than is normally used, hence requiring dilution before use.
CONDUCTIVITY A measure of the level of soluble salts in a growing medium.
CONIFER Popular name for cone-bearing trees belonging to the order Coniferales. Includes firs, cypresses, pines and spruces.
CORDATE Heart-shaped; similar to ovate (q.v.) but with more pronounced basal lobes.
CORIACEOUS Having a stiff or leathery texture e.g. as in the leaves of Sansevieria trifasciata.
COROLLA Collective term for the petals of a flower that may be separate or fused.
CORTEX The layer of tissue immediately below the epidermis (q.v.).
COSHH Control of Substances Hazardous to Health Regulations.
COTYLEDON The first leaf or leaves in a germinating seed.
CRENATE Leaf margin with shallow, rounded teeth.
CRISTATE With a crest-like growth in one area of the leaves, stems or flowers.
CROWN The basal part of a herbaceous perennial from which roots and stems grow.
CULTIVAR Short for “cultivated variety” and referring to a plant variety that has originated in cultivation, rather than in the wild.
CUNEATE Wedge-shaped; usually refers to leaves which taper from a broad tip to a slender base.
CUTICLE The waxy covering on leaves and stems that prevents excessive water loss.
CUTIN The complex material from which the cuticle (q.v.) is made.

D
DAMPING OFF A disease of plants, especially seedlings, encouraged by cold, wet soil and crowded conditions.
DECIDUOUS Describes plants that shed their leaves before the winter or dormant period.
DENTATE Leaf margin with outward-pointing teeth.
DENTICULATE Finely-toothed version of dentate (q.v.).
DICHOTOMOUS STEM One which repeatedly forks into two diverging branches.
DISTICHOUS Having leaves or flowers arranged in two vertical rows on either side of the stem.
DIVISION Highest category or grouping in the plant kingdom; sometimes called Phylum (q.v.). Also describes a method of propagation that involves splitting the root-ball into two or more sections.

E
EFFLORESCENCE The layer of crystalline salts sometimes found on the surface of old compost.
EMULSION CONCENTRATE A solution of an active ingredient in solvents together with emulsifiers that allows it to be diluted with water to the concentration required for use.
ENDEMIC A plant which grows naturally in a specific area/country and nowhere else.
ENDODERMIS The innermost layer of cells in a plant.
ENTIRE Having a smooth, undivided edge.
ENTOMOPHOBIA Morbid fear of insects.
ENZYME A protein that acts as a catalyst in a specific biochemical reaction.
EPIDERMIS The outermost layer of cells in a plant.
EPIPHYTE A plant without soil roots that is supported on other plants or rocks e.g. orchids, bromeliads. Also known as “air plants” they are not parasitic but get nourishment from the rainwater and debris that collects on their host.
EVERGREEN A plant that retains it foliage throughout the year, shedding and replacing a few leaves at a time.
EXOTIC A plant which is not native to the region.

F
F1 HYBRID The first generation offspring of two pure-bred strains.
FAMILY A group of similar genera (q.v.).
FASTIGIATE Of erect habit with a conical or tapering outline e.g. the Lombardy Popular.
FIELD CAPACITY The volume of water held by a growing medium after it has been saturated and allowed to drain.
FILIFORM Thread-like.
FLORET One of the tiny flowers that make up a larger, composite flower or inflorescence (q.v.).
FLOWER The reproductive part of seed-bearing plants.
FORM A term used to describe a sub-species, or any plant that varies slightly from the norm e.g. in flower colour or leaf shape.
FORMULATION The term given to describe the physical nature of the formulated active ingredient, e.g. wettable powder, gel, etc.
FROND Alternative name for the leaf of a fern or palm.
FUNGUS An organism without chlorophyll, which feeds on organic matter. The cause of many infectious plant diseases.

G
GENUS A grouping of species with similar characteristics e.g. Ficus, Dracaena. Collections of similar genera are grouped into families (q.v.).
GLABROUS Smooth or hairless.
GLOCHID A short, barbed hair, many of which form tufts on some species of cacti.
GROWING POINT The tip of a stem from which new growth develops.
GUARD CELL One of the pair of crescent-shaped cells that control the opening and closing of the stomata (q.v.).
GYMNOSPERM A member of one of the seed-bearing classes of plant.

H
HABIT The general or overall growth pattern of a plant e.g. bushy, conical, erect.
HARDY Able to withstand prolonged exposure to cold temperatures, including frosts.
HASTATE Triangular or spear-shaped.
HAZARD A possible source of danger.
HEARTWOOD The inner core of a woody plant which has ceased to contain living tissue but provides much of the mechanical support.
HERBACEOUS Without a woody stem.
HETEROPHYLLUS Bearing leaves of different shape and/or function on the same plant e.g. Hedera helix.
HETEROTROPHIC Describing an organism that feeds on organic matter produced by other organisms. Includes fungi and parasitic plants.
HONEYDEW The sweet, sticky secretion left on plants by insects such as whitefly and aphids.
HSE Health and Safety Executive.
HUMUS Organic constituent of soil, formed by the decomposition of plant and animal materials.
HYBRID Plant produced by cross-fertilising two plants of the same family but different species, variety or genera.
HYDROCULTURE The form of hydroponic (q.v.) cultivation and maintenance used for interior landscaping.
HYDROPHOBIC Repelling or having an aversion to water.
HYDROPONICS A method of growing plants in water. The roots are supported by a sterile medium such as LECA (q.v.) or sand and nutrients are added in a balanced liquid fertilizer.
HYGROMETER An instrument for measuring the humidity of the air.
HYGROSCOPIC Absorbing or attracting moisture from the air.

I
ILG Interior Landscape Group; section of BALI (q.v.).
INCIDENT An unforeseen occurrence which does not lead to injury to persons or damage to property, but which could do so in other circumstances.
INCISED Describing leaves with deeply cut or toothed margins.
INFLORESCENCE A general term for the part of a plant that bears the flowers.
INORGANIC Of mineral origin.
INTERNODE The section of stem between two nodes (q.v.).

L
LAMINA The main, usually flattened portion of a leaf. Also known as the leaf blade (q.v.).
LANCEOLATE Shaped like the head of a lance.
LATERAL BUD A bud which arises on the side of a main or leading stem.
LATEX Fluid exuded by some species of plant e.g. the milky secretion in Ficus benjamina.
LEAFLET Any segment of a compound leaf (q.v.).
LECA Trade name for round pebbles of fired clay used in hydroculture, as a drainage layer in the base of plant containers or as a decorative soil cover.
LENTICEL Any of the raised pores in the stems of woody plants that allow gas exchange between internal cells and the environment.
LETHAL DOSE 50 The measurement of toxicity of a pesticide needed to kill 50% of laboratory test animals when given either orally or dermally. Usually expressed as milligrams of technical material per kilogram of body weight (mg/kg).
LIGNIN An organic material that strengthens the cell walls of many plants especially trees.
LIP The lowest segment of orchid and similar flowers; it usually differs in colour or form from the other segments.
LOAM A soil consisting of fine clay, sand and decayed organic matter.
LUX A unit of illumination or brightness, equivalent to one lumen per square metre.

M
MERISTEM The extreme tip of a stem or root containing actively dividing cells.
MESOPHYLL The inner tissue of a leaf.
METABOLISM All the chemical processes that produce energy in a living organism.
MICRO-ENCAPSULATION The term given to the formulation of an active ingredient that has had a “plastic” coating added to it. This serves as a protective layer to allow the slow release of the active ingredient e.g. Osmocote granules.
MICRON One millionth of a metre.
MIDRIB The central vein (q.v.) of a leaf.
MITOSIS Cell division that results in two identical daughter cells.
MONA Trade name for a sub-irrigation system invented in Scandinavia.
MULCH A layer of organic material, such as bark chippings or leaf mould, that is spread over the growing medium for decoration or to retain moisture.

N
NECROTIC Describing dead plant tissue, which usually becomes darker in colour. A common symptom of fungal infection.
NEUTRAL Refers to a material, e.g. soil, water with a pH level of 7.0 i.e. neither acid nor alkaline.
NODE The point at which a leaf or bud joins the stem and from which lateral shoots grow out.

O
OASIS Trade name for a light, porous material used to support artificial and real cut flower stems in small displays.
OBOVATE Reversed ovate (q.v.), with the point at the stem end of the leaf.
OPPOSITE Refers to leaves borne in pairs, one on either side of the stem.
ORDER A grouping of similar families (q.v.). Similar orders are placed in classes (q.v.).
ORGANIC Of plant or animal origin.
OSMOSIS The passage of a solvent, such as water, through a semi-permeable membrane, from a dilute solution to a more concentrated one.
OVATE Egg-shaped; usually refers to the outline of a leaf, which may be slightly pointed.
OVOID Another word for ovate (q.v.) but more commonly applied to a whole object rather than just its outline.

P
PALISADE LAYER The layer of elongated cells just below the epidermis (q.v.).
PALMATE Describing a compound leaf that has the appearance of an outspread hand.
PARASITE (From Greek – Para = Beside, Site = Food) Organism which lives in or on another organism and feeds on it, for at least part of its life.
PATHOGEN A micro-organism that is capable of causing disease.
PATHOGENIC Causing disease.
PEAT Partially decomposed sphagnum moss or sedge extensively used in growing media.
PERENNIAL A plant that lives for many years.
PERICYCLE A layer of cells within the endodermis and most prominent in roots.
PETIOLE The slender stalk joining leaf to stem.
pH A measure of the hydrogen ion (H+) concentration, and hence of the acidity or alkalinity of an aqueous solution.
PHLOEM Vascular tissue whose principal function is the transport of sugars and other nutrients around the plant.
PHOTOSYNTHESIS The process by which green plants use the sun’s energy to convert carbon dioxide and water into carbohydrates.
PHYLUM The animal equivalent of “division” (q.v.) but now often used in its place.
PHYTOTOXIC Poisonous to plants.
PINCHING OUT Removing the growing points (q.v.) of a plant to stimulate branching lower down the stem.
PINNATE Describing a compound leaf with two rows of leaflets (pinnae) on either side of the midrib e.g. as in Nephrolepis exaltata.
PITH Plant tissue found in the centre of many stems and roots.
PLUMULE The embryonic shoot in a germinating seed.
POT BOUND A plant growing in a pot which is too small for further root expansion.

R
RADICLE The embryonic root in a germinating seed.
RELATIVE HUMIDITY The ratio of the actual to the maximum possible amount of water vapour in the air at a given temperature. Usually expressed as % RH.
RESISTANCE The ability of an animal to withstand the effects of a normally applied concentration of a chemical and to pass this on genetically to the next generation.
RESPIRATION The process by which plants break down sugars, taking up oxygen and releasing carbon dioxide.
RETICULATE Describing a leaf with a conspicuous network of veins e.g. Hedera helix.
RHIZOME A horizontal stem, usually growing underground, which produces roots and shoots and often acts as a storage organ.
RHOMBOID Almost diamond-shaped.
RISK The likelihood or possibility of suffering harm.
ROOT HAIRS Microscopic root projections responsible for absorbing water from the soil.
ROOT CAP A hood-shaped layer of cells at the tip of a root that protects it from abrasion as it grows through the soil.
RUGOSE Having a wrinkled or corrugated appearance.

S
SAGITTATE Shaped like an arrowhead.
SAP The solution of mineral salts and sugar that moves around a plant in the xylem and phloem vessels.
SAPWOOD The outer layer of wood which, in a growing tree, contains living tissue and reserve food materials.
SBS Sick Building Syndrome (q.v.).
SENSITISER An agent which causes an allergic reaction when in contact with skin or other parts of the body.
SERRATE Leaf margin with forward pointing teeth, rather like a saw.
SESSILE Stalkless leaves or flowers which emerge directly from the stem.
SHRUB Woody plant with a framework of branches but little or no central stem.
SICK BUILDING SYNDROME Symptoms such as headache, lethargy and eye irritation which appear to be more common amongst workers in so-called “sick” buildings than in others.
SIMPLE LEAF A leaf that is not divided into separate segments.
SINUATE Wavy-edged.
SOLUTION A liquid mixture of chemicals, e.g. solid in liquid or liquid in liquid.
SOLVENT A liquid other than water, which is capable of dissolving chemical substances.
SPADIX A fleshy flower spike with tiny florets embedded in its surface. Most commonly found in the Araceae family e.g. Spathiphyllum wallisii.
SPATHE The large, sometimes highly coloured bract that surrounds or encloses the spadix (q.v.).
SPECIES A group of individual plants, subordinate in classification to genus (q.v.), having members which may breed together and differ only in minor details.
SPORE The tiny, single-celled reproductive body produced by fungi, ferns and mosses. Equivalent to the seeds found in most other plants.
STANDARD Popular term for a tree-like plant with an unbranched main stem and compact head of foliage.
STOMATA (UK)
STOMATES (USA) Small pores, found predominantly on the underside of leaves, which allow air and moisture vapour to pass in and out of the plant (singular = stoma – UK, stomate - USA).
STOPPING Another word for pinching out (q.v.).
SUCCULENT A plant with thick and fleshy leaves, stems or roots capable of storing water.
SUSCEPTIBILITY The opposite of resistance. The condition where an animal is unable to withstand the normally applied concentration of a chemical.
SUSPENSION Insoluble particles uniformly distributed in a fluid.
SYMBIOSIS An intimate relationship between two or more different organisms, usually to their mutual benefit e.g. the nitrogen-fixing bacteria on tree roots.
SYSTEMIC A pesticide that is absorbed by a plant and transported throughout its tissue.

T
TAPROOT The main descending root of a plant.
TENDER A plant that is liable to injury from cold. Often applied to interior plants that require minimum temperature of 15?C (59?F).
TENDRIL A thread-like growth, usually arising from the leaf axil of a climbing plant, which twines around the supporting structure. In some cases the leaf stalks act as tendrils.
TERMINAL BUD The uppermost, usually central bud on a plant.
TERRARIUM A partly or entirely closed glass container used to house a collection of interior plants.
TESSELLATED Describing leaves and petals which are chequered with spots or marks in contrasting colours.
TOPIARY The art of clipping shrubs into ornamental shapes.
TOXICITY The capability of a chemical material to injure or kill. Measured by the lethal dose (LD%) needed to kill a specified percentage of test animals (usually 50%).
TRACHEID One of the needle-like cells that conduct water in softwood trees e.g. pine, spruce, and cypresses.
TRANSLOCATION The conduction of soluble materials from one part of a plant to another.
TRANSPIRATION The loss of water through a plant’s stomata (q.v.).
TRANSPIRATION STREAM The flow of water from the roots to the leaves.
TREE A woody perennial plant with a distinct stem or trunk.
TYPE Specimen having the essential characteristics of its plant grouping.

V
VARIEGATED Having leaves or flowers that are striped, spotted or otherwise patterned in more than one colour.
VARIETY A member of a plant species that differs from the others in some inheritable way e.g. colour, leaf shape. It should only be used for naturally occurring plants, not those bred in cultivation, which are called cultivars (q.v.).
VEGETATIVE Plant propagation by any method other than seed germination e.g. layering, grafting.
VEIN A strand of conducting tissue typically found in leaves. Large veins are sometimes called “ribs” and the central vein, extending from the petiole (q.v.) is called the midrib (q.v.).
VESSEL The tube-like duct which carries sap in most angiosperms.

W
WATERLOGGED Saturated with water.

X
XEROPHYTE A plant that is adapted to living in very dry conditions e.g. cacti, succulents.
XYLEM Woody vascular tissue used for transporting water and dissolved minerals.