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Glossary of Terms

Acid, alkaline—Descriptions of soil or water pH. Number 7 being neutral. A pH above 7 indicates alkalinity, and a pH less than 7 indicates acidity.

Aerate—Punch holes in, or loosen soil in order to allow better air circulation.

Annual—Plants which reach maturity in one growing season. The seed germinates; the plant grows, blooms, seeds, and dies within a year or less. Plants that have to be replanted each year in our climate are also referred to as annuals (e.g., marigolds).


Aphids—Small insects of assorted sizes and colors, usually oval in shape, which damage plants by sucking, plant juices.

Bacillus thuringiensis (Bt)—A bacterial disease sold under brand names such as Dipel, Thuricide, Bioworm, Caterpillar Attack, etc. A nontoxic way to kill caterpillars.

Bagworms—Insects that build baglike cocoons on conifers and other plants.

Balanced fertilizer—A fertilizer that contains, in equal or nearly equal proportion, some measure of the three primary fertilizing elements: nitrogen (N), phosphorus (P), and potassium (K).

Balled and burlapped (B & B)—A method of packaging plants and trees with a ball of soil around the roots, wrapped in burlap.

Bare root—A method of packaging dormant plants having no soil around the roots.

Biennial—A description of the life cycle of certain plants which require two years to produce seed.

Black spot—Leaf and stem fungus that primarily attacks roses.

Bonsai—Japanese meaning “to cultivate in a tray.” An Oriental art of growing dwarfed, carefully trained miniature plants. The purpose is to create a tree or landscape in miniature.

Border planting—Any plant or group of plants which acts as a barrier or boundary to segregate sections of a property.

Borers—Very damaging insects whose larvae bore holes in trees. A sure sign of plant stress.

Bract—Leaflike plant part, sometimes colorful, located below the flower or on the stalk of a flower cluster.

Bulb—Any plant that grows from a thickened underground structure. A true bulb is more or less rounded and composed of fleshy scales that store food.

Caliche—A rocklike deposit of calcium carbonate (lime) beneath the soil surface. This condition is found in the dry areas of the Southwest.

Cambium—A thin layer of tissue-producing cells between the bark and the sapwood of a woody plant.

Caterpillars and worms—Pests that come in hundreds of varieties. Most are moth and butterfly larvae that feed on foliage.

Chlorosis—The yellowing of leaves (especially between the leaf veins) caused by the lack of iron or other nutrients.

Complete fertilizer—A plant food containing the three primary elements: nitrogen, phosphorus, and potassium.

Compost—Organic matter that has been decomposed by a process of fermentation. An excellent soil conditioner, compost is also a mild fertilizer. The most important organic tool.

Conifer—A plant that produces seeds in cones and is usually evergreen. Their leaves may be needlelike (e.g., pines) or scale like (e.g., junipers).

Cool season grasses—Grasses that natively grow in cool climates, used here in shade areas and for winter over seeding (e.g., ryegrass, bent, fescue, Poa trivialis).

Corm—Like a bulb; thickened underground vertical stem which produces roots, leaves, and flowers during the growing season. It differs from a bulb in that food is stored in the solid center tissue, whereas food is stored in scales of bulbs.

Crown gall—A bacterial disease causing deformation at the base of plants at the ground line; especially prevalent on conifers and members of the rose family.

Cultivar—A horticultural variety that has originated under cultivation. Cultivar names are now formed from not more than three words and usually distinguished typographically by the use of single quotation marks, e.g., ‘Early Black.’

Cultivate—(1) To grow or plant domestically. (2) To hoe or dig around a live plant for the purpose of eliminating weeds and breaking up crusty soil.

Cutworm—Night-feeding worm that is particularly destructive to tender bedding plants.

Deciduous—Foliage drops in fall and returns in the spring.


Desiccation—Drying out and dying.


Diatomaceous earth (DE)—The skeletal remains (silica compounds and trace minerals) of diatoms—single-celled aquatic algae. An effective insecticide that works by the microscopic particles cutting an insect’s waxy outer coat and destroying its moisture balance.

Dioecious—Male and female flowers on different plants.

Division—Cutting or dividing root clumps and replanting.

Dormant—A period of time that a plant is not growing, normally winter.

Dwarf—A plant whose size has been reduced, either by nature or by vegetative means, such as grafting or budding onto a dwarfing understock. Many annuals have been hybridized to produce dwarf forms from seed.

Earwig—Long, thin, beetlelike insect that stinks when you step on it and feeds on flowers, other insects, and decaying organic matter.

Espalier—Shrubs or trees trimmed and trained to grow flat against a wall, fence, trellis, wire, etc., in a pattern or mass.

Evergreen—Foliage stays green all year and never loses all the leaves at one time.

Family—Groups of plants that share similar characteristics.

Fertilizer—Any plant food.

Fertilizer, water-soluble—Fertilizer that is mixed with water before applying.

Fireblight—A disease that strikes pyracantha, loquat, and other members of the rose family. It is characterized by the burned look of the tip growth.

Foliar feeding—The application of fertilizer by spraying the leaves of a plant with a mild liquid fertilizer solution.

Forcing—Hastening a plant to the flowering or fruiting stage out of its normal season; usually done by growing under controlled conditions indoors.

Foundation planting—Growing plants along the foundation of a building.

Friable—Loose and crumbly soil that permits air circulation and water drainage.

Gall—A rounded swelling on a leaf, twig, or stem of a plant, usually caused by fungi or insect stings.

Genus—A further breakdown (subcategory) of the family category of plants. The genus to which a plant belongs is the first word in a plant’s botanical name.

Germination—Earliest stage of the formation of a plant from seed.

Green lacewing—A beneficial aphid-eating insect.

Greensand—Texas greensand is from natural deposits in East Texas. Contains many trace minerals and about 19% iron.

Groundcover—Spreading plants that cover bare ground.

Hardening off—The process of slowly changing a plant’s light, temperature, water, or fertilization to prepare it for a change in weather or location.

Herbaceous—With the texture of a herb as opposed to a woody texture.

Herbicide—A chemical applied to the soil to control weeds. Selective herbicides kill only specific plants while leaving surrounding vegetation unharmed; nonselective herbicides kill all vegetation in the area to which they are applied.

Humus—The last stages of decomposition of animal or vegetable matter into a soft brown or black substance.

Hybrid—A plant resulting from the cross of two species.

Iron chelate—A combination of iron and a complex organic substance that assists in making iron readily available to roots of plants. Used to treat chlorosis.

June bug—Insect whose larva is the grubworm that does great damage to lawns.

Lacebug—Insect that is particularly bad on pyracantha.

Ladybug—Also called ladybird beetle. The best friendly insect that feeds on aphids and other small insect pests.

Lava Sand—Natural volcanic soil amendment used to increase the energy and the water-holding ability of the soil.

Leafhopper—Small insect with piercing-sucking mouthparts. These pests usually suck plant juices from the undersides of leaves.

Leaf miners—The larvae of various kinds of moths, midges, and flies. They feed inside the plant between the leaf surfaces and create serpentine trails or ugly blotches on the leaf.

Loam—Soil consisting of sand and light clay particles. Usually fairly big in organic material.

Mealybug—White fuzzy insect closely related to scale. It may appear singly or in groups on branches or twigs.

Monoecious—Male and female flowers on the same plant.

Mulch—Material placed on top of the soil which serves to reduce or prevent weed growth, insulate soil from drastic temperature changes, reduce moisture loss, and enhance the appearance of the bed. Peat moss, compost, bark, sawdust, straw, and leaves are examples of mulch.

N-P-K—Symbols for nitrogen, phosphorus, and potassium.

Naturalize—To plant or spread randomly. When plants are allowed to reseed themselves and grow as wildflowers, they have the ability to naturalize.

Naturalizing—The reverse of plant domestication. A naturalized plant is one that has “escaped” from the garden and grows wild, propagating itself. Plants are naturalized intentionally or by accident, as when the wind or animals transport the seed.

Nematodes—Microscopic wormlike organisms that attack the root systems of certain plants. Very hard to control. Some feed on insects and are beneficial.

Organic fertilizer—A fertilizer made from previously living matter or from animal waste. Common organic fertilizers include cottonseed meal, bone meal, dried blood, sewage sludge, animal manure, and compost.

Organic material—Any material that can be incorporated into the soil to improve its condition and was at one time a living substance. Peat moss, bark, compost, and manure are examples.

Ornamental tree—Small tree used more for decorative purposes than for shade. Normally used for color (flowers or colorful foliage) or for small areas or courtyards.

Peat moss—The partially decomposed remains of several different mosses. It is a spongy, organic soil additive which is highly water retentive and very acidic. Compost is a better choice in the South.

Perennial—Usually means a plant of which the top portion dies each winter and regrows the following spring; however, some keep their leaves year-round.

Perlite—Mineral used in container-soil mixes. It is very lightweight, white, porous, granular, and used for loosening and allowing more air into the soil.

pH—Abbreviation describing the acidity or alkalinity of soil or water, 7 being neutral, less than 7 being acid, greater than 7 being alkaline.

Pick pruning—Selectively removing limbs and branches rather than shearing.

Pleaching—The interweaving and plaiting together of plant branches. After this training method, subsequent pruning maintains a neat, somewhat formal pattern.

Pyrethrum—A natural insecticide derived from the pyrethrum flower or painted daisy, a variety of chrysanthemum.

Rhizome—A long and slender or thick and fleshy stem which grows horizontally along or under the soil.

Scale—Insect pests which are divided into armored and soft groups. Waxy secretions and hard skins cover the armored group. Soft scales usually secrete a substance which causes blackening of foliage and sticky film on cars, walks, etc.

Scarifying—Plowlike scratching or breaking up of the surface of the soil in order to loosen or aerate. Also refers to the treatment given to hard seeds to hasten germination.


Seedling—A young plant grown from seed.

Shade tree—Large-growing trees that provide a canopy top that allows other planting or activity to take place beneath.

Sharp sand—Washed sand, which is considered free of organic matter, used to make concrete and in planting bed preparation.

Shrub—A multiple-stemmed, usually small woody plant with an upright habit of growth.

Snails and slugs—Found where the ground is consistently moist. These pests inhabit groundcover plantings, where they hide during the day and feed on plants at night.

Soil test—An analysis of the fertilizing elements contained in the soil. Such a test is usually performed by a state department of soil conservation, but soil test kits are available commercially.

Sphagnum—A moss native to swamp conditions. These mosses are used in air layering and for lining hanging baskets.

Red spider—Tiny pests which cause damage by sucking sap (from lower leaf surfaces). Actually mites, not spiders. Webs will appear when the plant is under heavy infestation. Very hard to control.

Spider mites—same as red spider.

Spp.—Abbreviation used with botanical names after the genus to indicate that there are many different species of that particular kind of plant.

Stolon—A vinelike stem that grows along the ground or just under the surface and produces a new plant at its tip.

Succulent—A plant that is drought tolerant due to its ability to store water in its fleshy foliage.

Sucker—A weak shoot that grows quickly from the base of a plant or from the joint of two normal limbs.

Taproot—A main root which grows straight down. In dry areas some taproots grow very deep to reach a moisture source.

Tendrils—Threadlike projections found on some vines which enable them to climb and cling to supports.

Topsoil—The uppermost layer of soil.

Tree—A large upright woody plant.

Tree trunk goop—Mix one-third of each of the following in water and paint onto trunks of trees with insect problems: diatomaceous earth, soft rock phosphate, and manure compost.

Tuber—A short, thickened underground stem or root.

Tuberous root—An underground food storage structure with buds at the upper end of the root. Example is dahlia.

Understory tree—Small to medium size tree planted under the canopy of larger trees.

Variegated foliage—Foliage that is striped, blotched, or edged with some color other than green.

Variety—The subdivision of a species; a group of individual plants within a species which are distinct in form or minor characteristics, usually perpetuated through generations by seed.

Vermiculite—A heated and puffed-up mineral which forms spongelike, lightweight granules useful to add to container soil.

Vine—A long-stemmed plant that trails over the ground, or climbs if support is provided. Some vines climb by twining or by tendrils that cling to the support. Other vines must be tied to their support.

Wettable powder—A finely ground chemical which can be mixed into water and sprayed onto plants.

Whiteflies—Small, snow-white insects which are usually found in large numbers. Whitefly nymphs suck juices from the underside of leaves, damaging the plant.

Woody—Characterized by a woodlike texture as opposed to a herblike texture.

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