Glossary of Botanical and Horticultural Terms


Achene: A dry, indehiscent, one­seeded fruit.

Aciculate: Needle­shaped.

Acid soil: Soil with a pH level below 7.

Acuminate: Gradually tapering to an elongated point.

Acute: Sharply pointed with an angle less than 90 degrees.

Adpressed: Lying close and flat against.

Adventitious: Developing in an abnormal position.

Agamic: Asexual; reproducing by means other than seeds.

Air layering: Type of vegetative propagation carried out by means of a specially treated area of a branch, which is enclosed in a filmous sleeve until rooting takes place. The new plant can then be detached and planted.

Alate: Winged.

Alkaline soil: Soil with a pH level above 7.

Alternate: Of leaves when they are arranged at different heights on the stem.

Amplexicaul: With the base of the leaf encircling the stem

Anemophilous: Wind­pollinated.

Annual: A plant whose life cycle comprises a single growing season.

Anther: The part of the stamen which contains the pollen.

Anthesis: The time of opening of the flowers.

Aphid: Insect that sucks the juices from a plant’s tissue.

Arcuate: Bent in a bowlike curve.

Aristate: Bearded.

Articulate: Jointed.

Ascending: Rising somewhat obliquely and curving upwards.

Auricle: An ear-shaped projection or appendage.

Awl-shaped: Tapering from the base to a slender and stiff point.

Axil: The angle formed by a stem and a leaf stalk.

Axillary: Produced from the axil.

Bacciform: Berry­shaped.

Balled­and­burlapped: Describing a plant that is ready for transplanting, with a burlap­wrapped soil ball around its roots.

Bare­root: Describing a plant that is ready for transplanting, with no protective soil or burlap covering around its roots.

Bearded: Furnished with long or stiff hairs.

Berry: A fleshy, indehiscent fruit containing several hard­coated seeds.

Biennial: A plant that lives for two years or growing seasons, producing leaves the first season, and flowers and seeds the second.

Bifed: Two-cleft.

Bilabiate: An organ with two prominent parts rather like lips.

Bipinnate: A leaf that is twice pinnate.

Bisexual: A flower that contains both male organs (stamens) and female organs (pistils).

Blackspot: Fungus disease that produces black spots on leaves, which then yellow and fall off.

Blade: The expanded part of a leaf or petal.

Blanche: Whiten a plant’s leaves, stems or shoots by excluding light, e.g. by covering with soil.

Bloomy: With a fine, powder-like waxy deposit.

Bole: Trunk of a tree.

Bolt: Go to seed, especially prematurely.

Botrytis: Tiny fungus that causes many destructive blights.

Bract: A modified leaf below a flower, often showy, as in dogwood.

Bracteole: A small bract

Broad­leaved evergreen: A nonconiferous evergreen.

Broadcast: Scatter seed, fertilizer, or other materials over a large area instead of placing in specific rows or planting holes.

Bt: Bacillus thuringiensis, a bacteria that attacks and kills many common garden pests. It can be bought by the pound.

Bud: The initial phase of new organs of a plant­ branches, leaves or flowers.

Bulb: Encased leaf or flowerbud, as an onion or tulip.

Bulbil: A small bulb, sometimes produced by a plant instead of a seed.

Bullate: Having blisters or puckered.

Bush: A fairly small plant with numerous branches that spring from the base, almost synonymous with shrub.

Bushy: Having the habit of a bush with numerous branches originating from a single root.

Caducous: Not persistent; of sepals, falling off as the flower opens; of stipules, falling off as the leaves unfurl.

Calcareous: Soil rich in calcium carbonate (lime), alkaline, not acid.

Calcifuge: Avoiding calcareous soils.

Calyx: The outer parts of a flower, usually green.

Campanulate: Bell shaped.

Canaliculate: With the sides turned upwards, channeled.

Candle: On a conifer, the new budlike shoot that sends out young needles.

Cane: A long, often supple, woody stem.

Capitate: Head-like, collected into a dense cluster.

Capitulum: Type of inflorescence, as seen in the Compositae.

Capsulate: A dry dehiscent fruit that opens on ripening by parting of its valves thus its seeds are dispersed.

Capsule: A dry fruit containing seeds – having more than one cell.

Carina: The two lower petals of a papilionaceous flower; also known as the keel.

Carpel: The part of the flower which produces the seeds.

Catkin: A long flower cluster comprised of closely spaced, generally small flowers and prominent bracts, as in pussy willows.

Chlorophyll: Green coloring matter in plants, essential to photosynthesis.

Chlorosis: A yellowing of the leaves.

Chlorosis: Yellowing of the leaves, due mainly to mineral deficiencies or waterlogging, reflecting a deficiency of chlorophyll.

Ciliate: With a fringe of hairs on the margin.

Cladode: Flattened leaf-like stems.

Clavate: Shaped like a club, narrow at the base, swelling towards the apex.

Clay soil: A soil, usually heavy and poorly drained, containing a preponderance of fine particles. It is sticky when wet, and hard when dry.

Clayey: A soil type with a high proportion of clay.

Climber: A plant whose stem is unable to support it but which can climb upward by means of special vegetative features and by using whatever supports are available.

Clinging vine: A vine that climbs by attaching itself to a structure.

Clone: The vegetatively propagated progeny of a single plant.

Clump division: Reproduction of plants by dividing a crown or clump into two or more parts.

Coiling vine: A vine that climbs by coiling around another plant or structure.

Cold frame: A boxlike structure, set outdoors, in which seedlings, cuttings, and plants are grown; often used to extend the growing season.

Columnar: Tall, cylindrical or tapering, column-like.

Compost: Decomposed organic matter, usually used to enrich the soil.

Compound: Composed of two or more similar parts.

Conical: Cone shaped.

Conifer: Cone­bearing plant, usually evergreen.

Container­grown: Grown as a seedling in the container in which it is to be sold.

Cordate: Heart­shaped, with rounded lobes at the base.

Coriaceous: Of a semi­rigid consistency, Ieathery.

Corm: The fleshy, enlarged, underground base of a plant’s stem, by which the plant reproduces.

Corolla: The inner parts of the flower, comprising the petals, usually used when the petals are united into a tube.

Corymb: Flat­topped or rounded flower head with the outermost flowers opening first.

Corymbose: Arranged in corymbs or resembling a corymb.

Creeping: Trailing along the ground.

Crenate: With shallow, rounded teeth.

Cross­pollination: The transfer of pollen from one plant to another.

Crown: The site on a plant where root joins stem.

Culm: Stem of grasses.

Cultivar: A cultivated variety, produced by selective hybridization and denoted by a fancy name in inverted commas, e.g. ‘Loddon Pink’

Cultivate: To work the soil in order to break it up and/or remove weeds.

Cuneate: Wedge-shaped.

Cuspidate: Abruptly sharp pointed.

Cutting: A means of asexual propagation that consists of inserting parts (root, stem, leaf) of a plant into a suitable rooting medium; these will eventually produce roots and eventually new plants.

Cyme: A flat­topped or rounded flower head with the innermost flowers opening first.

Cymose: Having flowers in the cymes.

Damping off: Fungus disease that causes seeds and seedlings to rot and die.

Deadhead: To remove spent (dead) blossoms.

Deciduous: Losing its leaves during drought or at the end of the growing season; nonevergreen.

Decumbent: Trailing loosely onto the ground.

Decurrent: Extending down the stem.

Dehiscent: (Of fruits) that open spontaneously on ripening to disperse the seeds.

Deltoid: Triangular.

Dentate: Of a leaf margin that is sharply toothed.

Denticulate: With tooth­like projections.

Depressed: Flattened from above.

Die back: Process by which a plant appears to die back to the ground during its dormant period; the plant begins growing again in the spring.

Digitate: With the members arising from one point (as in a digitate leaf).

Dioecious: Bearing male flowers on one plant and female flowers on another (e.g. Ilex, Holly).

Diploid: Containing twice the basic number of chromosomes (the usual complement).

Direct seeding: Sowing seeds directly into the garden rather than starting seeds indoors.

Disbud: Remove buds to encourage production of larger or more flowers.

Dissected: Divided into many narrow segments.

Divaricate: To branch out, separate widely.

Divergent: Spreading.

Divided: Separated to the base.

Division: The removal of suckers from a parent plant, for the purposes of propagation.

Double serrate: Large teeth and small teeth alternating.

Double: In flowers, having an increased number of petals, produced at the expense of other organs.

Downy: Softly hairy.

Drainage: The ability of the soil to move water so that the roots of the plant do not become waterlogged, and so nutrients move through the soil.

Drupe: A fruit with a fleshy middle and a single hard seed (kernel), the whole being enclosed in a tough outer skin.

Dwarf: A shrub with a mature height of three feet or less.

Elliptic: In the shape of an ellipse, tapering at both ends with the broadest part across the middle.

Emarginate: With a shallow notch at the apex.

Entire: Undivided and without teeth.

Ericaceous: In the heath (Erica) family.

Espalier: To train a plant to grow flat against a structure, usually in a decorative pattern.

Evergreen: A plant that seems to retain its leaves all the time but which is continually replacing them during the periods of vegetative rest.

Exfoliate: To self­peel, as bark.

Exserted: Sticking out, usually of the style or stamens from the flower.

Falcate: Sickle-shaped.

Family: A group of plants sharing common features and distinctive characteristics; a group of related genera.

Fastigiate: With branches erect and close together.

Ferruginous: Rust­colored; reddish­brown.

Fertile: Having the capacity to generate seed.

Fertilizer: Any material that supplies nutrients to plants.

Filament: The stalk of the anther; together they form the stamen.

Fimbriate. Fringed.

Flexuous: Wavy, usually of a stem.

Floccose: Clothed with flocks of soft hair or wool.

Florets: Small, individual flowers of a dense inflorescence.

Floriferous: Flower-bearing, usually used to indicate profuse flowering.

Forma: A minor variant, less different from the basic species than a variety. Abbreviated to f. or ff. if plural.

Foundation planting: A massed planting designed to mask, disguise, or enhance the foundation of a house or building.

Friable: Ready for cultivation, easily cultivable, as soil.

Gamopetalous: With petals partly or entirely fused to each other.

Gamosepalous: With sepals partly or entirely fused to each other.

Genus: A group of related species.

Germinate: To develop a young plant from seed; to produce a seedling.

Germination: The beginning of plant growth from a seed.

Gibbous: Swollen, usually at the base.

Glabrous: Smooth, without hair. .

Glandular: With glands, which are usually stalked, like hairs with a sticky blob on the apex.

Glandulous: Covered with hairs that emit a viscous fluid when touched.

Glaucous: Blue­hued; covered with a bluish or grayish bloom.

Globose: More or less spherical.

Glutinous: Sticky.

Grafting: A system whereby a union is formed between plants of different species by means of notching and the insertion of a shoot; the shoot is intended to become the main feature although the basic stock is usually more robust and its growth has to be strictly controlled.

Groundcover: A plant with a low­growing, spreading habit, grown specifically to cover the ground.

Habit: A plants characteristic form of growth.

Harden off: The process of gradually accustoming a young, indoor-started plant to the outdoors.

Hardpan: Soil sufficiently compacted, or clogged with clay or other particles that draining is impossible.

Hardwood cutting: Cutting taken from a mature woody stem for the purpose of propagation.

Hardy: Plants which can withstand freezing temperatures.

Hastate: With a broad but pointed apex, and two diverging lobes at the base.

Herbaceous: Of a non­woody perennial, which dies down to the ground after flowering .

Herbaceous: Without woody tissue.

Hermaphrodite: Male or female flowers in the same inflorescence.

Heterophyllous: A plant that bears more than one form of leaves.

Hirsute: With rather course or stiff hairs.

Hispid: Covered with long stiff hairs or bristles.

Hoary: Covered with a close whitish or greyish-white pubescence.

Holdfast: The rootlike part of a clinging vine that adheres to a support.

Humus: Soil composed of decaying organic matter.

Hyaline: Transparent, often soft or papery.

Hybrid: A cross between different species, subspecies or varieties.

Imbricated: Overlapping.

Imparipinnate: A pinnate leaf with a single leaflet at the tip.

Incised: With deep cuts in the margin.

Indehiscent: Not opening when ripe; i.e. a seedpod.

Indumentum: A massing of fine hairs, glands, or prickles.

Inflorescence: The flowers and flower stalks, especially when grouped.

Infructescence: Fruit formed from an inflorescence.

Insecticidal soap: Soap formulated to kill, repel, or inhibit the growth of insect pests.

Insecticide: A product that kills insects.

Integrated pest management (IPM): A philosophy of pest management based on the idea of using escalating methods of pest control, beginning with the least damaging; incorporates the selection of resistant varieties, the use of biological and nontoxic controls, and the application of pesticides and herbicides only when absolutely necessary.

Internode: The portion of stem between the two nodes or joints.

Invasive: Tending to spread freely and wantonly; weedy.

Involucre: A whorl of bracts surrounding a flower or flower cluster.

Keel: A central ridge.

Knot garden: Herb garden formally planted in tight patterns.

Lace bug: Insect which has broad, lacy wings and sucks sap from plants.

Lacerate: Torn, irregularly cut of cleft.

Laciniate: Deeply and irregularly toothed and divided into narrow lobes.

Lanceolate: Shaped like a spearhead, widest below the middle, with a tapering point.

Lateral: On or at the side.

Lax: Loose.

Layering: The development of roots on a stem while it is still attached to a parent plant, for the purposes of propagation. See also air layering and simple layering.

Leaf mold: A form of humus composed of decayed leaves, often used to enrich soil

Lime: Calcium carbonate, often added to the soil to reduce acidity.

Leaflet: One division of a compound leaf.

Legume: A dry dehiscent fruit, typical of the leguminous plants, which splits open on both sides when ripe to disseminate the seeds.

Liana: A climbing and twining plant (usually tropical).

Linear: Long and narrow, with parallel sides.

Lips: One of the parts of an unequally divided flower.

Loam: A best of soil – well­drained soil, usually containing a significant amount of decomposed organic matter.

Lobate: (Of leaves) divided into lobes.

Lobe: Any protruding part of an organ (as in a leaf, corolla or calyx).

Lyrate: With a broad, but pointed apex and lobes becoming smaller towards the leaf base.

Manure: Organic fertilizer of animal origin, rich in nitrogen.

Mealybug: White, cottony-looking insect that attacks plants.

Microclimate: Climate specific to a small area; may vary significantly from that of surrounding areas.

Mildew: Fungal disease that produces white dust or downy tufts on leaves.

Monocarpic: Usually dying after flowering and fruiting.

Monoecious: A plant separately bearing both male and female flowers.

Monotypic: A genus comprising only of one species.

Mosaic: Virus disease that causes mottled, yellow, curled leaves and discolored fruit.

Mucronate: Terminated abruptly by a spiny tip.

Mulch: An organic or inorganic soil covering, used to maintain soil temperature and moisture and to discourage the growth of weeds.

Named cultivar: A cultivar that has been given a recognized horticultural name.

Naturalize: To escape from a garden setting and become established in the wild.

Nectary: The part of the flower which produces nectar.

Nematode: Microscopic wormlike animal that may be beneficial or harmful to plants.

Neutral soil: Soil having a pH of 7–neither acid nor alkaline.

Nitrogen: One of the three most important plant nutrients, needed for the production of leaves and stems. It is required for all living plants and animals since it is a component of protein. If the supply of nitrogen is good, foliage is green and the plant flourishes. Insufficient nitrogen is indicated by yellowing leaves and stunted growth. Too much nitrogen may cause excessive growth, making plants more susceptible to disease. (See also Phosphorus and Potassium).

Nitrogen deficiency: Frequently shows up as a yellowing of the mature leaves of the plant, and a general slowing in the growth rate. Because nitrogen has a dramatic effect on the growth of plants, it should be applied only when plants are growing, not when they are dormant.

Node: The point on a stem where the leaves arise.

Nodose: With knot­like protuberances.

Nut: A non-splitting, one-seeded, hard and bony fruit.

Nutrients: Elements in the soil absorbed by plants for growth.

Oblanceolate: Shaped like a spearhead, but widest above the middle.

Oblique: Unequal-sided.

Obovate: Inversely ovate.

Obtuse: Bluntly pointed, with an angle greater than 90 degrees.

Offset: A short, lateral shoot by which certain plants are propagated.

Open-pollinated: Pollinated by the wind or animals, not by human manipulation.

Orbicular: Almost circular in outline.

Orbicular: Almost round.

Organic gardening: Practice of gardening without the use of synthetic chemicals.

Organic matter: Part of the soil that consists of decayed or decaying plant and animal matter (humus).

Organic: Derived naturally, from living or once­living matter.

Ovary: The lower part of the pistil containing the ovules.

Ovate: (Of leaves) egg­shaped – broader than lanceolate.

Ovule: The internal organ of the ovary that becomes a seed after fertilization.

Palmate: With lobes or leaflets, spreading like the fingers of a hand.

Panicle: A branched raceme.

Paniculate: Having flowers in panicles.

Papilionaceous: Butterfly­shaped flower, which is characteristic of one division of the Leguminosae.

Pappus: Calyx modified into a downy or scaly material, often resembling a ring of fine hairs to aid wind dispersal.

Paripinnate: A compound pinnate leaf with an even number of leaflets.

Peat moss: Partially decomposed sphagnum moss, often added to soil to increase moisture retention.

Peat: A material resulting from the decomposition of plants. It is commonly added to soil to make it lighter, more moisture­retentive and more nourishing.

Pectinate: Comb-like (as in leaf margin).

Pedicel: The stalk of a flower cluster or of a solitary flower.

Pedicel: The stalk of a single flower in a cluster.

Peduncle: The stalk of an inflorescence.

Pellucid: Clear, transparent (as in gland).

Peltate: Shaped like a round shield, with the stalk in the center.

Pendulous: Hanging, weeping.

Perennial: A plant that lives for more than one growing season, at least three and some to twenty years or more.

Perfect: Having stamens and pistils; bisexual, as a flower.

Perfoliate: A pair of opposite leaves fused at the base, the stem appearing to pass through them.

Perianth: The outer part of the flower.

Perlite: Volcanic glass used in seed-starting and growing mediums.

Persistent: A leaf, bract, etc. that remains on a plant for more than one growing season.

Pesticide: A product that kills garden insects.

Petal: Part of a flower’s corolla, outside of the stamens and pistils, often vividly colored.

Petaloid: Petal-like (as in stamen).

Petiole: A leaf stalk.

pH: The hydrogen ion content of soil; the symbol used to express the acidity or alkalinity of soil; if the pH is equal to 7, the solution is neutral; if it is over 7, it is alkaline, and if less than 7, it is acid.

Phosphorus: One of the three important plant nutrients and is essential in all phases of plant growth, but is particularly associated with early maturity of crops, the formation of seeds and fruits, and increased root growth. Increased resistance to disease is another benefit. If the supply of phosphorus is too low the existing phosphorus will move from the older tissues to the younger tissues. Therefore, the usual visible signs of a lack of phosphorus appears first in the lower leaves, which are the older ones. The symptoms may be a lack of chlorophyll, a deepening of the green color, or a reddish color in the leaves. Phosphorus deficiencies are often difficult to detect because of the effect of phosphorus is only apparent underground, in the root system of the plant. Phosphorus does not move through the soil, but remains where placed, therefore, to ensure that phosphorus reaches the plant roots, mix with the soil in the hole for new plants, and mix in the soil down around existing plants as close to the roots as possible. Good organic sources are, manure, bonemeal and powdered rock phosphate. (See also Nitrogen and Potassium).

Photosynthesis: Process by which plants capture energy from the sun and convert it into compounds that fuel growth and life.

Pilose: Covered with hair.

Pinch: Snip back to new growth, to keep plants compact and encourage bushiness.

Pinnae: Leaflets of a pinnate leaf.

Pinnate: Describes a leaf in which the leaflets are positioned on either side of a central stalk (axis).

Pinnatifid: With lobes on either side of a central axis.

Pinnule: A small pinnae.

Pioneer: A plant that flourishes in disturbed soil, as after a fire.

Piriform: Pear­shaped.

Pistil: The female part of a flower consisting of the ovary, style and stigma.

Pleaching: Or plashing, means intertwining the upper branches of regularly positioned shrubs or trees to form an impenetrable barrier, hedge or screen.

Plumose: Feather, as the down of a thistle.

Pollen: A collection of tiny grains that develop in the anthers and which contain the male gametes.

Pollination: The movements of pollen from one flower to another, necessary for fertilization and therefore fruit production.

Polygamous: Bearing bisexual and unisexual flowers on the same plant.

Pome: A fleshy fruit .

Potassium: One of the three most important plant nutrients. It is essential for the growth of plants, and plants take large amounts of it from the soil. It is not known exactly what role potassium performs in the living processes of a plant cell, but there is some evidence that it acts in enzymatic processes, especially the transformations among different kinds of sugars. It is known, however, that potassium functions within the plant in a number of special ways. This nutrient increases the resistance of some plants to disease and it aids in the formation of oils in oil-bearing seeds. It improves the rigidity of stalks, and helps plants overcome the effect of adverse weather or soil conditions. When potassium deficiency becomes severe, applications of potassium cannot correct the damage already done, especially in short-season plants such as annuals and vegetables. Good organic sources are greensand and small amounts of wood ashes. (See also Nitrogen and Phosphorus).

Potassium deficiency: Because one of the most apparent signs of a potassium deficiency in plants is a general slowing of growth, it is difficult to tell if a plant is suffering from such a deficiency unless you can compare it to a similar plant that is growing normally.

In this photograph, the leaf on the left is from a healthy plant; the other two leaves indicate a plant’s potassium deficiency.

Potash: Another name for potassium. The name orininates from colonial days when wood and other organic materials were burned in pots for the manufacture of soap. The ashes were rinsed with water; this rinse water was collected and allowed to evaporate. The residue was largely potassium salts. Today, potassium is mined in a similar manner to rock phosphate.

Potbound: Condition of pot-grown seedling or plant whose rootball is thickly matted and contains little soil.

Procumbent: Trailing along the ground; prostrate.

Propagate: To grow new plants from old, under controlled conditions.

Propolis: A red or brown resinous substance produced by the buds of some plants and used as glue by the bees; in solution, it is a natural pesticide.

Prostrate: Trailing along the ground; prostrate.

Pruinose: Bloomy.

Pruning: The cutting away of branches or dead parts of a plant, or the shortening of living branches to certain nodes; it is a skilled operation requiring some study.

Puberulent: With a fine but rather sparse covering of hairs.

Pubescent: With a fine coating of hairs, denser than puberulent.

Punctate: With translucent or colored dots or depressions.

Pungent: Ending in a stiff, sharp point, also acid (to the taste) or strong-smelling.

Pyramidal: Pyramid-shaped (broad at base tapering to a point).

Pyrethrum: Insecticide made from chrysanthemums

Raceme: A long inflorescence whose flowers, held on short stalks, get progressively shorter toward the end; the terminal flower is the last to open.

Racemose: Having flowers in racemes.

Rachis: An axis bearing flowers or leaflets.

Ramble: To grow freely, often over another plant or structure.

Reflexed: Abruptly downward or backward.

Rejuvenation pruning: The practice of cutting all the main stems of a shrub back close to the ground during winter dormancy; renewal pruning.

Remontant: Able to rebloom one or more times during a single growing season.

Renewal pruning: See Rejuvenation pruning.

Reniform: Kidney­shaped.

Reticulate: With veins arranged in a net­like form.

Revolute: Rolled backwards, margin rolled under.

Rhizome: An underground modified stem, often swollen and fleshy.

Rib: A prominent vein in a leaf.

Rootbound: A condition where the roots have become so overgrown within a container that they often grow in a circular path and fill the container leaving little room for soil.

Root cutting: A cutting taken from the root of a parent plant for the purpose of propagation.

Root pruning: The act of removing a portion of a plant’s roots to keep top growth in check.

Root: The part of a plant that is generally underground and anchors it in the soil absorbing the nutriment and moisture necessary for growth.

Rootstock: The part of the plant from which the roots and the stems arise – the root of a grafted plant.

Rosette: An encircling ring of leaves.

Rostrate: With a beak­like part.

Rotenone: Biological insecticide.

Rotund: Nearly circular.

Rufous: Reddish-brown.

Rugose: Wrinkled or rough.

Runner: A prostrate branch that roots at its joint.

Rust: Fungal disease that produces rust-colored blotches on leaves

Sabadilla: Insecticide made from a Mexican plant of the lily family.

Sagittate: Shaped like an arrowhead.

Samara: An indehiscent fruit with a single seed equipped with a wing­like membrane to facilitate wind dispersal; e.g. a ‘key” from a maple.

Sandy soil: Soil with a high percentage of sand, or large soil particles. Water travels through sandy soil every easily, so nutrients leach (wash) out quickly.

Sap: A liquid that runs through plants and which constitutes their nutritive essence.

Scabrous: Rough to the touch.

Scale(1): A minute leaf or bract, or a flat gland-like appendage on the surface of a leaf, flower or shoot.

Scale(2): Insect that forms a brown dome around itself on a place.

Scandent: With climbing stems.

Scape: A leafless flower stalk rising from the ground.

Scarify: To sand, scratch, or otherwise disturb the coating of a seed in preparation for its germination.

Self­pollination: A plant’s ability to fertilize its pistils with its own pollen.

Scarious: Dry and papery, usually also transparent.

Seed: The reproductive organ of plants derived from the fertilized ovule and containing the embryo of a future plant.

Seeding: A young plant, especially one grown from seed.

Semidouble: Having more than the usual number of petals but with at least some pollen­producing stamens.

Semievergreen: Retaining its leaves for most of the winter, or in warm climates.

Semihardwood cutting: A cutting taken from a stem that has just begun to develop woody tissue, for the purpose of propagation.

Sepal: The part of a flower that is circularly arranged outside the petals.

Sericeous: Covered with soft down; silky.

Serrate: Sharply and finely toothed.

Serrulate: Minutely serrate.

Sessile: Without a stalk.

Set: (Fruit) develop fruit or seeds after pollination.

Setose: Clothed in bristles.

Sheath: Basal part of some leaves that wraps around the branch or stem. A semi­tubular structure surrounding some part of a plant.

Shoot: Young herbaceous growth that can be used for cuttings.

Shrub: A woody plant with branches from the base with no obvious trunk.

Sidedress: Apply fertilizer along the side of a seed row or around a plant.

Simple layering: Type of vegetative propagation achieved by pegging a flexible branch down to the ground where it will strike rootsafter a certain time. The new plant can then be detached and planted.

Simple: Said of a leaf that is not compound or an unbranched inflorescence.

Single: In flowers, having only one layer of petals.

Sinuate: Strongly waved (as in leaf margin).

Sinus: The recess or space between two lobes or divisions or a leaf, calyx or corolla.

Slug: Slimey, short, worm-shaped creature that eats leaves.

Softwood cutting: A cutting taken from a green, or immature stem of a woody plant for the purpose of propagation.

Spadix: A spike of small flowers on a fleshy stem enclosed by a spathe.

Spathe: A specialized leaf enclosed by a spadix.

Spathulate: With a broad, rounded apex and tapering into a narrow stalk.

Species: A basic category of classification. A species is composed of similar but distinct individuals that interbreed freely among themselves but not among other species. Abbreviated to sp. or spp. if plural.

Specimen: A plant deliberately planted by itself to emphasize its ornamental properties.

Spicate: Flowers in spikes.

Spider mites: Insects that rasp chlorophyll off broadleafed plants.

Spine: A woody, sharp­pointed body.

Spittlebug: Suckering insect that deposits a small bit of spittle (a bunch of bubbles) on a plant’s stem.

Sport: A plant that differs conspicuously from other members of its species, usually because of a mutation.

Spreading: Having a horizontally branching habit.

Stamen: The male organ or a flower, the pollen­bearing part of the flower, usually made up of anther and filament.

Staminode: A sterile stamen, often a flattened filament.

Staminoid: A pollenless stamen.

Standard(ize): A shrubby annual or perennial plant which has been trained to have a single straight stem, free of branches, to emulate a tree form.

Stellate: Star shaped.

Stem: The fundamental organ of a plant, above the roots, which serves to support all the other organs (branches, leaves, flowers) and to conduct the nutritive substances so that they will reach the extremities.

Sterile: Unable to generate seed.

Stigma: The sticky terminal part of the flower which receives and stores the pollen.

Stolon: A creeping and rooting, usually underground stem which produces new plants.

Stratify: To help seeds overcome dormancy by cleaning and drying them, then maintaining them for a period of time under generally cool and moist conditions.

Striate: Slightly ridged or striped.

Strigose: Clothed with flattened fine, bristle-like hairs.

Style: The connective tissue linking the ovary to the stigma.

Subcordate: Almost heart­shaped.

Suborbicular: Almost round, but usually slightly narrower.

Subshrub: A shrub that is woody only at the base.

Subspecies: A division of a species, with minor and not complete differences from other subspecies, usually distinct either ecologically or geographically. Abbreviated to subsp. or subspp. if plural.

Substrate: The substances of which the soil is composed on which a plant will grow.

Subulate: Awl-shaped.

Succession planting: Process of planting a new crop as soon as the earlier one is harvested.

Succulent: A fleshy plant, typical of dry climates, that has the ability to retain large amounts of water in the leaves and stem.

Sucker: A shoot growing from the root or base of a woody plant.

Suckering: Producing underground stems; also the shoots from the stock of a grafted plant.

Suffrutescent: A plant with a woody structure in its lower parts on which it produces tender shoots of a herbaceous consistency.

Tap root: A strong, vertical­growing, central root.

Tasciculate: In clusters.

Taxa: Refers to a taxonomic group of any rank, e.g. genus, species, cultivar, etc.

Tender Perennial: Dies down over winter, and emerges the following growing season where winters are not severe.

Tendril: A threadlike (filiform) organ derived from a leaf or branch, which is able to attach itself to a support and twine round on itself, thus supporting a weak stem.

Ternate: In threes.

Tessellated: Mosaic-like (as in veins).

Tetragonal: Having 4 angles and 4 convex faces.

Tetraploid: With four times the basic number of chromosomes.

Thin: Pull up or pinch young plants so remaining plants have room to grow and mature.

Thrips: Insect that rasps chlorophyll off broadleafed plants.

Tomentose: (Of leaves) densely covered with short, soft, matted woolly hairs.

Topiary: The art of trimming or training plants into decorative three­dimensional shapes.

Transplanting: The transfer of a plant from one site to another.

Tree: A woody plant that produces normally a single trunk and an elevated head of branches.

Trifoliate: Divided into three leaflets.

Trigonal: Triangular in cross section.

Tripartite: A leaf divided into 3 segments almost to the base.

Triploid: With three times the basic number of chromosomes: these plants are usually sterile, but robust growers and good garden plants.

Truncate: Ending abruptly, as if cut off at right angles.

Trunk: The woody stem of a tree.

Truss: A flower cluster set at the top of a stem or branch.

<Tuber: A fleshy, underground stem or root of a plant, by which the plant reproduces.

Tuberous Root: These nutrient storage units look like tubers but are really swollen roots. During growth, they produce fibrous roots to take in moisture and nutrients.

Tubiform: Cylindrical.

Turbinate: Shaped like a top or inverted cone.

Twining vine: A vine that climbs by coiling around another plant or structure.

Type: Strickly the original (type) specimen, but often used in a general sense to indicate the typical form of cultivation.

Umbel: An inflorescence in which the flowers are arranged like the spokes of an umbrella.

Umbelliferous: A plant bearing umbels.

Umbilicate: Having a navel­like depression.

Understock: The stock or root plant onto which a shoot has been grafted to produce a new plant.

Understory plant: A plant whose natural habitat is the forest floor.

Undulate: Wavy, usually of the edges of a leaf.

Unisexual: A flower that only has male (stamens) or only female (pistil) organs.

Urceolate: Pitcher­shaped, with a large body and small mouth, usually describing a corolla.

USDA Hardiness Zones: Planting zones established by the United States Department of Agriculture, defined by a number of factors, including minimum winter temperatures.


Variegated: Characterized by striping, mottling, or other coloration in addition to the plant’s general overall color.

Variety: A unit of classification below species or subspecies, composed of individuals differing from the species in very minor characteristics. Adjective varietal, abbreviated to var. or vars. if plural.

Velutinate: With a velvety surface.

Venation: The arrangement of the veins.

Vermiculite: Lightweight, highly water-absorbent mineral used in seed-starting and growing mediums.

Verticil: An arrangement of leaves grouped around a node, a whorl.

Verticillate: Arranged in a whorl or ring.

Vexillum: The large petal standing up at the back of a papilionaceous flower.

Vine: A plant that trails, clings, or twines, and requires support to grow vertically.

Weeping: Having long, drooping branches.

Whiteflies: Tiny flies that suck a plant’s juices; often look like a cloud of smoke.

Whorl: Three or more flowers or leaves arranged in a ring.

Wilt: Disease that causes leaves to turn brown; often causes sudden death of plant.

Winter kill: The dying back of a plant or part of a plant due to harsh winter conditions.

Woody: Forming stems that mature to wood.

Xeriscaping: Landscaping with the use of drought­tolerant plants, to eliminate the need for supplemental watering.