Gardening Glossary: Essential Gardening Terms Explained

Gardening comes with its own vocabulary, from annuals and biennials to mulching, propagation and soil pH. This A–Z gardening glossary explains common gardening terms in clear, straightforward language.

A

Acidic soil

Soil with a pH below 7. Acid-loving plants include blueberries, rhododendrons, camellias and many heathers.

Aeration

The process of introducing air into soil, lawns or compost. Aeration helps roots and beneficial microorganisms access oxygen.

Annual

A plant that completes its entire life cycle—from seed to flowering and seed production—within one growing season.

Bare-root plant

A plant sold without soil around its roots, usually while dormant. Bare-root roses, trees and fruit bushes are commonly planted during autumn or winter.

Bedding plant

A plant grown mainly for seasonal displays in beds, borders, containers or hanging baskets.

B

Biennial

A plant that usually grows leaves during its first year, then flowers, produces seed and dies during its second year.

Blanching

Excluding light from part of a plant to produce paler, more tender growth. Celery, chicory and rhubarb may be blanched.

Bolting

When a plant produces flowers and seeds earlier than expected, often because of heat, drought or another form of stress.

Border

A planted area positioned beside a lawn, path, wall, fence or other garden feature.

Broadcast sowing

Scattering seeds evenly across the soil surface rather than planting them in individual rows or holes.

C

Chitting

Encouraging seed potatoes to produce short shoots before planting.

Chlorosis

Yellowing of plant leaves caused by a lack of chlorophyll. It may result from nutrient deficiencies, unsuitable soil pH, damaged roots or disease.

Cloche

A transparent cover placed over plants to provide protection from cold weather, wind or pests.

Cold frame

A low, covered structure used to protect plants, raise seedlings and harden off young growth.

Companion planting

Growing particular plants together because one may benefit the other by attracting pollinators, confusing pests or making efficient use of space.

Compost

Decomposed organic material used to improve soil structure, moisture retention and biological activity. The word can also refer to manufactured growing media used in pots.

Compost tea

A liquid made by steeping compost in water. Homemade compost teas vary greatly and should be used with suitable hygiene precautions.

Cotyledon

A seed leaf that appears when a seed germinates. Cotyledons often look different from the plant’s true leaves.

Crown

The point where a plant’s stems and roots meet.

Cultivar

A cultivated plant variety selected for particular characteristics. Cultivar names are usually written inside single quotation marks, such as Malus domestica ‘Gala’.

D

Damping off

A fungal condition that causes seedlings to collapse and die, usually in wet, poorly ventilated conditions.

Deadheading

Removing faded flowers to improve appearance and encourage some plants to produce more blooms.

Deciduous

A plant that loses its leaves seasonally, normally during autumn or winter.

Division

A propagation method that involves splitting an established plant into several rooted sections.

Dormancy

A period when plant growth slows or temporarily stops, commonly during winter or dry weather.

Double digging

A traditional method of deeply cultivating soil to approximately two spade depths. It is rarely necessary in established no-dig gardens.

Drainage

The movement of excess water through soil or growing media. Poor drainage can deprive roots of oxygen and encourage rotting.

E

Earthing up

Drawing soil or compost around plant stems. It is commonly used when growing potatoes and leeks.

Ericaceous

Describes acid-loving plants or the acidic compost used to grow them. Rhododendrons, azaleas, blueberries and camellias are ericaceous plants.

Evergreen

A plant that retains living foliage throughout the year, although individual leaves may still be replaced.

F

Fertiliser

A natural or manufactured material that supplies plant nutrients. Fertilisers may be granular, powdered, pelleted or liquid.

Fleece

A lightweight horticultural fabric used to protect plants from frost, wind and certain pests.

Foliar feed

A diluted fertiliser applied directly to plant leaves, where some nutrients can be absorbed.

Forced plant

A plant encouraged to grow, flower or crop earlier than normal by controlling temperature, light or darkness.

Frost pocket

A low-lying area where cold air collects, making frost damage more likely.

G

Germination

The process by which a seed begins growing and produces a root and shoot.

Grafting

Joining part of one plant to the rooted section of another so that they grow together as a single plant.

Green manure

A crop grown mainly to protect and improve the soil. It is later cut down, incorporated or left on the surface as organic matter.

Growing medium

The material in which a plant’s roots grow. It may include soil, peat-free compost, coir, bark, sand, grit or other ingredients.

H

Half-hardy

A plant that cannot tolerate frost and normally needs protection or indoor propagation before being planted outside.

Hardening off

Gradually acclimatising indoor-raised plants to cooler, windier outdoor conditions before planting them permanently outside.

Hardiness

A plant’s ability to survive cold or other challenging environmental conditions.

Hardy annual

An annual plant capable of tolerating cool conditions and light frost. Many hardy annuals can be sown directly outside.

Herbaceous perennial

A non-woody plant that lives for several years. Its top growth may die back in winter before returning from the roots in spring.

Humus

Stable, well-decomposed organic matter within soil. Humus contributes to soil structure and nutrient retention.

Hybrid

A plant produced by crossing two genetically different parent plants. F1 hybrids are bred to produce consistent first-generation offspring.

I

Invasive plant

A plant that spreads aggressively and may overwhelm other plants or natural habitats.

Irrigation

The controlled application of water to plants or soil through watering cans, hoses, sprinklers, drip systems or other methods.

L

Layering

A propagation method in which a stem is encouraged to produce roots while it remains attached to the parent plant.

Leader

The main upright stem of a tree or shrub.

Leggy

Describes weak, elongated plant growth, often caused by insufficient light, overcrowding or excessive warmth.

Loam

A fertile soil containing a balanced mixture of sand, silt and clay.

M

Manure

Animal waste mixed with bedding material and used to improve soil. Manure should normally be well rotted before being used around plants.

Microclimate

The climate of a small, specific area that may differ from the surrounding garden. Walls, slopes, trees and buildings can all create microclimates.

Mulch

A layer of material spread over the soil surface to suppress weeds, retain moisture, protect roots or improve soil.

Mycorrhizal fungi

Beneficial fungi that form relationships with plant roots and may help plants access water and nutrients.

N

Native plant

A plant that occurs naturally in a particular region without having been introduced by people.

Naturalise

To allow plants to establish and spread in an informal way. Bulbs are often naturalised in lawns or beneath trees.

Nematode

A microscopic roundworm. Some nematodes damage plants, while beneficial species are used as biological controls against pests.

Node

A point on a plant stem where leaves, buds, branches or roots may develop.

No-dig gardening

A growing method that avoids routine digging. Organic matter is applied to the soil surface, where worms and microorganisms gradually incorporate it.

O

Organic matter

Material derived from living or once-living organisms, including compost, leaf mould, manure and decomposing plant material.

Overwintering

Keeping a plant alive through winter so it can grow again the following season.

P

Peat-free compost

A manufactured growing medium that does not contain peat. It may be made using materials such as bark, wood fibre, coir, green compost and loam.

Perennial

A plant that lives for more than two years.

pH

A scale measuring how acidic or alkaline soil or water is. A pH of 7 is neutral, lower values are acidic and higher values are alkaline.

Pinching out

Removing the growing tip of a young shoot to encourage bushier growth and additional side shoots.

Plug plant

A small young plant supplied in an individual cell or compact root plug.

Pollination

The transfer of pollen between flowers, allowing fertilisation and seed or fruit production.

Pot-bound

Describes a plant whose roots have filled its container and begun circling tightly around the root ball.

Potting on

Moving a plant into a slightly larger container as it grows.

Pricking out

Transferring young seedlings from a seed tray into individual pots or cells.

Propagation

Producing new plants from seeds, cuttings, division, layering, grafting or other methods.

Pruning

Removing selected stems or branches to control plant size, improve shape, encourage flowering or remove damaged growth.

R

Raised bed

A growing area raised above the surrounding ground and normally contained by timber, brick, stone, metal or another edging material.

Root ball

The mass of roots and growing medium removed from a container or lifted with a plant.

Rootstock

The rooted lower portion of a grafted plant. It can influence the plant’s eventual size, strength and disease resistance.

Runner

A horizontal stem that grows across the ground and produces new plants. Strawberries commonly spread by runners.

S

Scarification

Scratching, nicking or otherwise weakening a hard seed coat to help water enter and encourage germination.

Seedling

A young plant that has recently germinated from seed.

Self-fertile

A plant capable of producing fruit using pollen from the same plant or variety.

Self-seeding

The natural process in which plants drop seeds that germinate without deliberate sowing.

Soil amendment

A material added to soil to improve its physical, chemical or biological properties.

Soil conditioner

A material used primarily to improve soil structure, water retention or biological health rather than to provide concentrated nutrients.

Succession sowing

Sowing small quantities of seed at intervals to create a longer, more continuous harvest.

Sucker

A shoot growing from a plant’s roots, underground stem or rootstock.

T

Tender plant

A plant that is easily damaged or killed by frost and cold temperatures.

Thinning

Removing some seedlings or young fruits to give the remaining ones enough space to develop properly.

Tilth

The physical condition and texture of cultivated soil. A fine tilth is often prepared before sowing small seeds.

Top dressing

Applying compost, fertiliser, sand or another material to the soil or lawn surface.

Topiary

The practice of clipping evergreen plants into formal shapes.

Transplanting

Moving a plant from one location or container to another.

V

Variety

A naturally occurring or cultivated variation within a plant species. In everyday gardening, the term is often used loosely for named cultivars.

Vermicompost

Organic material processed by composting worms. The finished worm castings are used as a nutrient-rich soil amendment.

W

Waterlogging

A condition in which soil remains saturated, leaving too little oxygen around plant roots.

Weed

A plant growing where it is not wanted. Some weeds are valuable to wildlife but may compete with cultivated plants.

Wilt

Loss of firmness in plant stems or leaves, commonly caused by insufficient water, damaged roots, heat, disease or waterlogging.

Woody plant

A plant that develops persistent, firm stems, such as a tree, shrub or climber.

X

Xeriscaping

Designing and planting a garden to reduce the need for irrigation, often by choosing drought-tolerant plants and improving soil coverage.