Terms and Definitions

How many times during conversation with gardeners, or while reading a gardening article, have you thought “what the heck does that mean??”  Sometimes it is a term you have heard many times and think “I should know this”, or “I don’t quite understand”.  There are so many terms from the commonly used to specialized and scientific, it really is hard to keep track of it all.  This little glossary of gardening terms can be a quick reference to help you understand the basics and to check on less commonly used terms.

Accent plant:  A single plant strategically placed to draw attention to a point with its’ color, form or texture.  Sometimes referred to a focal point or anchor plant, around which a garden bed or theme is developed.

Acid soil:  Soil with a pH lower that 7.0, sometimes referred to as “sour soil”.  The lower the pH reading, the higher the acidity.  Regions that receive high amounts of rain are often more acidic and may more often be a sandy soil.

Acid medium:  Compost material with little or no lime and that has a pH level of less than 6.5.

Acre:  A parcel of land that measures 43,560 square feet.  A square acre measures 208.75 feet on all four sides.

Acuminate/acuminata/acuminatus:  A Latin botanical term referring to a sharply pointed feature or tapered point.

Adult phase:  The mature phase of a plant when it is able to produce fruit and or flowers.

Adventitious:  Growth of a plant part where it normally would not occur.  New shoots growing from a trunk would be an example. An adventitious plant is a whole new plant that develops asexually on the stem of another “mother” plant.  Kolanchoe (a tropical succulent flowering plant) is a common example.  Might also refer to a plant species growing outside its’ natural area, introduced accidentally.

Aeration:  Loosening or making openings in the soil to increase air and water penetration.  For a garden or planting area this is usually accomplished by digging or using a cultivator or tiller.  For the lawn, an aerator cuts and pulls out small plugs thru out the lawn at frequent intervals.

Aerial root:  A root that grows from the stem above ground.    This is most commonly seen on philodendron.

Aerobic:  With oxygen.  Commonly used to describe a compost heap that is aerated by turning the heap to keep it loose and full of oxygen.  Organisms living within only occur with oxygen present.

Air Layering:  A propogation method used for woody plants.  The bark of the plant is cut into to induce roots to form.  The stem is then kept consistently moist by surrounding with damp sphagnum moss and generally wrapped in a bag to hold the moisture.  When roots are developed, the lower portion of the stem is cut off, and the new plant is planted.

Alba/albus/album:  A Latin botanical term meaning white.  Generally referring to flowers.

Albo-maculata:  A Latin botanical term meaning spotted with white.

Albo-marginata:  A Latin botanical term meaning edged in white or with white margins.  Generally referring to leaves.

Albo-striata:  A Latin botanical term meaning striped with white.  Generally referring to variegated plants.

Alkaline soil: Soil with a pH higher than 7.0, sometimes referred to as “sweet soil”.  The higher the pH reading, the more alkaline the soil is.  Regions that receive low amounts of rainfall are often more alkaline.  Very dry gardens and planting areas may be more alkaline.  Lime from cement may be washed into the soil along driveways and building foundations, causing the soil to become alkaline.

Allelopathic plant:  A plant that emits chemicals that affect nearby plants’ growth.  Typically the effect is negative, inhibiting growth of neighboring plants  Black Walnut is a commonly known allelopathic plant.

Alpina/alpinus:  A Latin botanical term that can refer to an alpine plant or a dwarf plant.  It can also be used to refer to a smaller species with a large genus.

Alpine:  Plants native to high mountain regions or rocky areas.   They overwinter below deep snow, which protects them from extreme temperatures.

Alpine House:  A greenhouse that specifically meets the requirements of alpine plants.  The glass is shaded in summer to keep the plants cool, and is not typically heated in winter.

Alternate Leaves: Leaves that grow singly at different levels on the stem, alternating on one side of the stem and then the other.

Altissima/altissimus/altissimum:  Tall in comparison to other species.

Amendments:  Ingredients added to soil.  Typically referred to as soil amendments, and may include compost, peat moss, sand, as well as many other materials, both inorganic and organic.

Amurensis/amurense:  A Latin botanical term meaning from the Amur region of Asia.  Plants so named are generally very cold hardy.

Anaerobic:  Without oxygen.  Commonly used to describe a compost heap that is not aerated, the organisms living within occur only when oxygen is not present.

Anatomy:  The structure of a plant and the relationship between its’ parts.

Anchor root:  A large root that holds a plant in the soil.

Annuals:  Plants and flowers that grow for only one season.  A true annual completes its’ lifecylce in one year or less.  The seed germinates, grows the plant, blooms, produces seeds and then dies.  Some plants are considered annuals because they can’t survive the winter  Some annuals in a cold climate can be a perennial in warmer climates that don’t have freezing winters.  Annuals are generally planted in the spring and die with the first frost or hard freeze.  Annuals flowers can provide a lot of color all season long.

Anther:  The male part of a flower that produces pollen.  The anther is on the upper section of the stamen. 

Anthracnose:  A blight on a leaf, shoot or twig.  Usually caused by enfection form a fungus.  Certain trees are susceptible to the blight including ash, dogwood, maple, sycamore and white oak.

Apex:  The tip of a leaf or flower petal.

Asexual:  A propagation technique where plants are reproduced without a seed.  This is generally accomplished by rooting a cutting or by division.

Backfill:  Fill a hole with its’ original soil after you have planted, covering the roots with the soil.

B & B (Balled and Burlapped):    Larger shrubs and trees are dug out of the ground keeping the roots intact with a large “ball” of soil.  This ball is then wrapped in burlap to hold the soil, protecting the roots.  With the burlap in place, these can be watered and kept healthy for a short time until planted.  Some gardeners will plant the shrub or tree leaving the burlap in place.  The burlap will disintegrate relatively quickly, and the open and porous burlap will allow water and nutrients in.  Roots are also able to push themselves through fairly easily as the begin to grow before the burlap in disintegrated.

Bare Root:  Plants that are shipped or sold with no soil, literally bare roots.  They are removed from the ground while still dormant, the soil shaken and washed from its’ roots, and stored in cool conditions to keep them dormant until sold or shipped.  Bare root plants, perennials, roses and trees, are often less expensive when purchased bare root in very early spring.  The roots must be kept moist and cool and planted as quickly as possible.  Some gardeners feel that a bare root plant, when properly handled, will get off to a better start and have a superior first season compared to a potted plant.

Basal:  The lowest part of the plant or stem.  Basal leaves would be lowest set of leaves on the stem.

Bedding Plant:  Nursery grown plants, generally annuals, that are appropriate to plant in garden beds, containers and pots, and hanging baskets.  Bedding plants are often used for mass plantings to produce quick and long lasting color and full coverage with colorful blooms or foliage.

Bicolor:  A flower with petals of two distinct colors.

Biennial:  A plant that completes its’ life cycle in two season (lives for 2 years).  This first year is generally to produce the plant itself, the second year the blooms and seeds are produced.  The seeds will produce new plants, creating a never ending cycle of first year plants and plants in bloom, having the effect of  perennials.  Common biennials are hollyhocks and foxgloves.

Bolt:  When a plant grows too quickly, then blooms and sets seeds too soon.  This will often happen in very hot weather or because of late planting.  The term typically refers to vegetables.  The plant will flower and go to seed without producing the food crop.

Border:  A planting at the edge of an area.  A Border Garden is generally considered a planting area that follows the edge of a structure such as a fence, sidewalk or home.

Botanical name:  The Latin scientific name for a plant, typically made up of two or more names.  The genus name is first, then the species.  If there is a third name it is for the cultivar or specific variety of the plant.  All two or three names together make up the botanical name.  If you want to be sure of getting a specific plant, make sure you are asking for, and receiving the plant with the complete botanical name.  Using common names can be confusing and sometimes incorrectly identified.

Bud eye:  A potential growth point that may produce a stem, a leaf or a flower..  Generally identified as a small “swelled” area or “knot” on a stem.

Bud union:  A swollen and distinct node that will produce a stem or set of leaves.

Bulbs:  Some perennial flowers that emerge in spring, such as daffodils and tulips,  grow from a bulb.  The bulb is the underground storage organ of the plant.  It is generally a thickened fleshy “bulb” between the plant that emerges in spring and the roots from below the bulb, with a tough protective covering.  The bulb protects, and contains, the food for the developing plant inside.

Capsule:  A dry fruit pod that contains many seeds.  The capsule will split open to release the seeds.

Cell pack:  A plastic or peat container holding individual plants.  Cell packs are usually 4 or 6 cell units.  Cell packs may be sold individually or in flats.  A flat is a large shallow tray constructed to hold several cell packs.

Container Grown:  Any plant, tree, shrub or perennials, that is grown in containers for resale, rather than grown in the ground and later potted up for sale.

Cold frame:  A framed structure usually with a clear lid that can be opened fully or partially to allow for ventilation to protect young plants from cold weather.

Common name:  A commonly used name by gardeners to refer to specific plants.  They common names can vary by country and region, and may also refer to more than one specific plant, so it is difficult to know if you are getting the right plant.  At the garden center, try to refer to plants by botanical names to be sure.

Complete fertilizer:  A plant food that contains the three major nutrients: Nitrogen; Phosphorus and Potassium.

Compost:  An organic mixture of decayed vegetative matter and manure.  Used as an excellent natural fertilizer, mulch or to improve soil.

Compound leaves:  A set of leaflets, two or more but usually many, attached to a single leaf stalk.

Compound flower:  A flower head that appears to be a single bloom, but is make up of many tiny florets.  Often there is an outer ring of petals surrounding an inner center of small flowers, such as zinnia, chrysanthemum and sunflower.

Corm:  An underground stem that is rounded and contain buds. 

Cultivar:  A named variety.  A man made form of a plant, usually propagated by horticulturists by cross pollination or vegetative propagation.  This is often done to achieve a unique or improved plant.  The name given to a new cultivar is often in reference to the horticulturist, the nursery or the university involved in the propagation.

Cultivate:  Breaking up the topsoil to allow for air and water penetration, often removing weeds in the process, to prepare the soil for planting.  Generally accomplished with a garden hoe or tiller.

Cuttings:  A piece of stem, root, bud or leaf cut from a plant to propagate a new plant.  The cutting is placed in a growing medium until it develops roots.  Sometimes referred to as a slip.

Damping off:  A fungal disease afflicting seedlings, causing them to rot and die.  Over watering can promote the disease.

Deciduous:  Plants that lose their leaves once each season, usually in late autumn.

Dead Head:  The process of removing spent blooms by snipping or pinching off.  Dead heading will often encourage a plant to rebloom, encourage more blooming, or prevent it from seeding.  Deadheading also keeps the plant neat and sometimes healthier.

Determinate:  Plant growth stops at a certain height, generally in reference to tomato plants.

Dieback:  The gradual dying of a plant beginning at the tips and shoots.  Caused by disease, pests, cold or chemicals.  Can also be caused by lack of water or nutrients, or pruning injury.  Winter dieback refers to the death of topgrowth due to freezing temperatures.  In this reference, the plant will regrow from its’ roots next season.

Direct seed:  To sow seeds directly into an outside garden.

Division:  A technique used to propagate plants by dividing up the roots or bulbs by cutting or pulling apart.  Each division will produce a new plant.

Dormant:  A period of arrested plant growth enabling the plant to survive a climatic condition unsuitable for growth.  Winter cold or summer dry seasons can trigger dormancy.  The plant will often die back to its’ roots, and will regrow when conditions are favorable.

Dorsal:  The surface of a leaf or petal that faces toward the center of the plant.  Usually referring to the “underside”.

Drip line:  A ground level line circling a plant at the tip of its’ outermost branches.  This is a line where rain water will drip off at.  Within the line, roots are most concentrated.  This area is also a sheltered microclimate, receiving less rain, wind, and sunlight.

Dwarf:  A plant that is bred to grow smaller than its’ parent, usually as much as 1/4 or less in size.  A dwarf is not always identical to the parent plant.

Espalier:  A technique of training a tree or shrub to grow in a flat manner against a wall or other structure.  Generally the branches are pruned and trained to grow horizontally.  This technique is used for decorative purposes, but also to allow the plant to absorb maximum sunlight.  This will allow fruit to mature more quickly, or allow a plant to succeed in a cooler climate where, otherwise, it would fail.

Established:  When a plants roots have become firmly rooted and the plant begins to show new growth.

Everblooming:  Blooms nearly constantly throughout the growing season.

Evergreen:  Plants whose leaves remain alive year round.  Typically thought of as plants with needles rather than broadleaves.  There are, however, broadleaf species that do not lose their leaves, such as rhododendron (the leaves do go dormant and change color).  And temperate climate plants retain their leaves and grow throughout the seasons, year after year.

Everlasting:  Flowers that can be dried without losing their form or their color.  Asters, daisies, zinnias and helichrysum are some examples.

Falls:  The lower, downward drooping petals of the iris bloom.

Fibrous roots:  A root system that is fine and well branched, with many root hairs and growing laterally close to the soil surface.  No taproot is present.

Flats:  A large shallow tray constructed to hold several cell packs of plants.  May also be a large shallow tray for starting seeds in.

Floret:  One of many small flowers that make up the flower cluster of a compound flowerhead.

Floriferous:  Bears many blooms freely.

Foliage:  Considered as a group, the leaves of a tree/shrub, or the collective of a plant’s leaves, stems and flowers.

Foundation planting:  Plants installed along the foundation of a house or structure.  There is a misconception that there are specific plants best suited to this purpose.  Foundation plantings’ purpose is to hide an unattractive foundation, soften hard lines, and to add “insulation and wind protection” to the foundation.  Therefore, small dense shrubs are often used.

Friable:  Soil that is loose and crumbly, easily cultivated.

Frost hardy:  Plants that are damaged by frosts.

Frost heaving:  Plants may be pushed up out of the soil due to repeated thawing and freezing of the soil, typically in spring.  If this happens, gently push the plant back into place to protect the roots.

Frost tender:  Plants that may be damaged or killed by even a light frost.

Genus:  A scientific name for a category of plants, subdividing a larger family.  The plants are closely related with similar characteristics in structure, growing habits and flowers.

Germinate:  The sprouting of a seed, the first beginning of growth.

Grafting:  A propagation method that joins two plants together.  Typically joins a desirable plant to a hardier rootstock, such as a tender rose bush to the hardy, disease resistant stem and roots of a less pleasing rose.  Also used for ornamentals and fruit trees.

Green manure:  Not manure at all, but rather a fast growing cover crop (hence, “green”) such as ryegrass, that improves the nitrogen and nutrients in the soil much as manure wood.

Ground Cover:  A plant that is often used in relatively large numbers to cover bare earth and develop a uniform appearance.  They are generally a category of perennial that is low growing, but can also refer to larger plants, or small shrubs, that may be used for the same purpose.

Growing point:  The tip of a stem, from which the stem or branch elongates (grows).

Growth bud:  Buds along a stem or at the tip of a stem, that produces growth, generally a leaf or branch.

Habit:  The general form or shape of a plant.

Half hardy:  Applied to annual plants, they are able to survive a frost, but not subfreezing temperatures.

Harden off:  To gradually expose a plant  to the outdoors over a period of a couple of weeks before transplanting to an outside garden.  Daily exposure is increased a little at a time.  Young plants that were seeded indoors or plants that were wintered indoors must be hardened off.

Hardiness:  The ability of a plant to survive specific climate regions.  It is important to know the USDA zone you live in to select plants that are hardy enough to survive your growing conditions.  Hardiness can apply to an ability to survive regions with very cold winters, regions with very hot summers, as well as very wet or very dry regions.

Hardscaping:  The installation of non living features in a landscape.  This can be paver paths, driveways and sidewalks, retaining walls, patios, etc.  They are generally considered a permanent installation to facilitate a specific usage.

Hardy annual:  An annual plant that can withstand subfreezing temperatures for short periods, and whose seedlings can withstand spring frosts.  These annuals can be planted before the frost free date, and will often remain green or even blooming after a freeze in late autumn.  Seeds of some hardy annual will survive subfreezing winters and germinate in spring, allowing for autumn sowing.

Hardy perennial:  This term is generally referring to Winter hardy, which would be a perennial that is able to survive subfreezing temperatures in winter.  The actual hardiness is rated according to the USDA zones (climate zones).  In other words, some perennials may be hardy to the average low temperatures in zone 5, others may be able to survive the average low temperatures in zone 2.  Hardiness can also refer to dry and arid conditions, wet rainy conditions, tropical heat, etc.  However typically this term is applied to winter conditions.

Heeling In:  A temporary “planting” of a bareroot tree, rose or shrub, until a permanent site is prepared, or until weather conditions are appropriate.  The bareroot plant is placed at a 45 degree angle in a trench in a protected spot, and cover the roots with at least 8 inches of soil.  This is most often used to protect a plant from freezing temperatures until the weather is warm enough for permanent planting.  The plant should be moved to its’ permanent home as quickly as possible.

Heirloom:  A plant or seed that has been passed down through generations.  They are open pollinated plants and may have little disease resistance.

Herbaceous:  Plants that have non woody stems.

Herbicide:  Chemical applied to kill undesirable plants and weeds.

Hips:  Seed pods developed by a rose after the bloom has faded.  Not all roses produce hips.

Hybrid:  A plant or seed that is the result of cross pollinating parents with different traits to produce a new cultivar.  Seeds of a hybrid plant will not come up true to the original plant, but will revert back to or favor one of the parents.

Indeterminate:  Plant growth continues indefinitely until the top is pinched off or until killed by frost.  Generally refers to tomato plants.  The plant will require staking.

Landscape:  Often incorrectly used to refer to plantings.  Landscape encompasses the complete physical features of a piece of property including plants, lawn, pavement, structures, water features, etc.

Layering:  A propagation technique for woody plants.  A long, young, and flexible stem is secured to the ground (usually simply by burying the tip in the soil) to encourage it to root, thereby creating a new plant.  This method is commonly used to propagate roses.

Mutation: A naturally occurring genetic mutation that changes the color, shape, stems or other physical characteristics of a plant. Mutations are actually quite common. Hybrids may display a change of bloom color or a single petal color from one of its’ parents, typically a random and non-recurring phenomenon. A favorable mutation that is stable is a sport, and is sometimes propagated as a new variety.

Native Plants:  Plants that have grown naturally in a specific area or climate before permanent human settlement.  Native plants are a good choice for gardens and landscapes due to their natural ability to survive the specific growing conditions without much human intervention for fertilization and watering.  If the “native” conditions have been dramatically altered (such as in a larger city), it is possible that a plant that was one native to the area may no longer be suitable for current conditions.

Neutral soil:  Soil with a pH level of 7.0, neither acid nor alkaline.

Node:  The point on a stem where a stem, branch, leave or bud is attached.

Organic Gardening:  A method of gardening that uses no chemical or synthetic fertilizers of pesticides.  Fertilizers are derived only from once living things.  Insect and fungus deterrents range from application of natural material to physical removal or natural predators for insects.

Organic Fertilizer:  Fertilizer obtained from a source that is, or has been alive, such as manure, compost or peat moss.

Organic Material:  Any material that began as a living organism.  Typically referring to material added to soil, such as peat moss, manure or compost.  Also would include any naturally occurring plant or animal material in the soil.

Organic Seed:  A seed that has been produced and harvest without the use of inorganic chemicals, chemical fertilizer or hormones.

Pavers:  Small concrete pieces formed or shaped for using to form a walkway, driveway or patio.  They are generally formed to appear like brick or cobblestone, and are available in a variety of colors.

Pelleted Seed:  Seeds that are very small can be coated with inert material such as clay so that they are easier to handle and plant.

Perennials:  Herbaceous (not woody) plants that die back to the ground each fall and regrow each spring.  To be considered a perennial, they must regrow for at least three years.

Potting Soil:  A specific mix of soil that is ideal for growing plants in containers, pots, window boxes or hanging baskets.

Propagation:  To produce new plants.  There are a variety of techniques for propagating plants, including planting seeds, division, rooting cuttings, and layering.

Repeat Bloomer:  A plant that will bloom off and on throughout the growing season after short periods of no blooms.

Rootstock:  Root system of a hardy variety that is used to graft a desirable rose or rose standard.

Self Pollinating:  A plant that does not require pollen from another plant to produce fruit.

Semi Evergreen:  A plant that retains its leaves in mild regions, but drops them in cold regions.

Sour soil:  Acid soil with a pH lower than 7.0.  “Sour” does not mean fouled or bad, as a matter of fact there are many plants that prefer “sour soil”.

Sport: A naturally occurring mutation, creating a new variation of a plant. These mutations are typically not recurring and if found to be stable will be propagated as a new variety and is called a Sport.

Standard:  A shrub or herb plant that is grown in tree form with an erect central stem.

Subshrub:  A partly woody plant.  Generally the base of the plant is woody, stems are non woody and bushy.

Succulents:  Plants that have leaves and/or stems that are fleshy (non woody) and very watery.  They often have a waxy outer layer that allows them to retain large amounts of water very well.  (Cactus and Sedum are examples of succulents.)

Sucker:  Growth from the rootstock of a grafted plant.  These small plant shoots are considered undesireable.

Sweet soil:  Alkaline soil with a pH higher than 7.0.  “Sweet” does not mean the soil is better in any way, as a matter of fact some plants cannot tolerate a “sweet soil”.

Tender Annual:  An annual plant that can be damaged or killed by a frost (a brief period of temperatures hovering around the freezing point).

Tender Perennial:  A perennial plant that can be damaged or killed by subfreezing temperatures.  These are plants that are considered perennial in warm climates, but are “annual” in cold climates, or may be overwintered indoors.

Top Soil:  “Black Dirt” that is appropriate to use in lawns or in the garden.

Tuber:  Fleshy underground stems.  Each short section contains a bud and can potentially produce a new plant.

USDA Hardiness Zones:  Geographic zones separated by a number of weather conditions and environmental factors.  Plants are rated to grow well or survive according to the zones numbers. 

Wall Blocks:  These concrete blocks manufactured for building retaining walls or borders are often known by various retail trade names (Anchor Block, Keystone Blocks, Versa-Lok Blocks, etc.).  They are manufactured with a lip that overlaps lower blocks to lock it into place and prevent movement by soil heaves and water displacement.

Woody Plants:  A plant that has woody stems, such as shrubs, trees and evergreens.