PlantAdvice.co.uk - Glossary of Gardening Terms

Glossary of Gardening Terms

If you’re not quite sure what a gardening term or phrase means, check out the following descriptions of common terms and phrases below.

A -

Annual - Life cycle of one year: Describes a plant that germinates, grows, flowers, sets seed and then dies all in the course of one growing season. E.g. Marigold (Many bedding plants are annuals). See our list of annual and biennial plants.
Aril - Seed coat: The fleshy coating to some seeds. E.g. the bright red aril of the Yew berry surrounds the seed.

B -

Biennial - A plant with a two year life cycle: A plant that germinates, grows, flowers, sets seed and dies all in the space of two years. See our list of annual and biennial plants.
Bract - Modified leaf: A modified leaf. Often brightly coloured. e.g. Poinsettia. The distinctively coloured leaves at Christmas time are in fact bracts.

C -

Calcareous - Soil type: Describes a soil or compost that has a high pH value (above 7 on the pH scale) Certain plants prefer calcareous soil or compost. e.g. Pulsatilla.
Calyx - Flower part: Part of the flower, at the base of the petals, often in a whorl arrangement of petal-like sepals.
Chlorophyll - Leaf pigment: The green pigment in the leaf that absorbs the sunlight for use in photosynthesis.
Conifer - A plant that produces naked seeds.: The term conifer is used to describe a plant that produces naked seeds, usually on the scales of cones. Conifers are also usually evergreen trees or shrubs.
Corm - A stem storage organ: A type of storage organ for storing food for the plant similar to a bulb but consisting of a modified stem or stem base.
e.g. Cyclamen.
Cultivar - A variety of cultivated plant: The word CULTIVAR is derived from the two words CULTIivated and VARiety. A cultivar is a cultivated plant having unique characteristics that distinguish it from others of the same species. These characteristics were developed under cultivation and remain when the plant is propagated.

D -

Deciduous - Drops leaves after growing season: Describes a plant that drops its leaves at the end of each growing season. e.g. An Oak tree (Quercus robur).
Dicotyledon - Germinates with 2 seed leaves: A Dicotyledon is a plant that has two seed leaves when it germinates. E.g. All grasses are Dicotyledons.
Dioecious - Bearing male and female flowers on separate plants: A Dioecious is a plant that bears male and female flowers on separate plants. E.g. Holly (Ilex).

E -

Epiphyte - A plant growing on another for support: An Epiphyte is a plant that grows on another plant, using it for stability and support, although not feeding from the supporting plant.
E.g. Many members of the Orchid group are epiphytes.
Ericaceous - Soil type: Describes a soil or compost with a low pH value (below 7 on the pH scale) usually referred to as ‘acid soil’. Certain plants require ericaceous soil or compost to thrive. e.g. Rhododendron and Camellia. See our list of ericaceous plants.
Espalier - Training method: A recognised form of training trees. Opposite branches are trained horizontally from the central stem. This method is most commonly used to train fruit trees.
Evergreen - A plant that retains its leaves all year round: Evergreen plants retain their leaves throughout the year, with each leaf lasting for more than 12 months. Older leaves are gradually shed over a period of time.

G -

Graft - Propagation technique: When plant material from two separate plants are artificially joined together usually by a skilled nursery worker. E.g. Many apple trees are grafted, the top growth being a different variety to the rootstock.
Green Manure - Plants used to improve soil: A crop specifically grown to be dug into the soil resulting in soil improvement and enrichment. E.g. broad beans are often grown as a green manure crop.

H -

Hardy - Tolerance of adverse weather: A general term used to describe a plant’s ability to withstand adverse weather conditions. Most commonly used to describe a plant’s ability to survive varying temperatures.
Herbaceous - Summer foliage, winter rootstock: A plant that over-winters as a rootstock, with foliage that dies back at the end of each growing season. E.g. Peony (Paeonia).

L -

Layering - Propagation technique: A method of propagation. A plant shoot is pinned to the soil for a period of time, whilst still attached to the parent plant. The shoot develops it’s own roots at this point and is then cut from the parent plant.

M -

Monoecious - Separate male and female flowers on same plant: The term used to describe a plant that has separate male and female flowers on the same plant.

N -

NPK - Nitrogen (N) : Phosphorous (P) : Potassium (K): The chemical elements Nitrogen (N), Phosphorus (P) and Potassium (K) used in plant fertilisers. The percentages of these elements are often found on the label of fertilisers. The percentages are shown as numbers, e.g. 10-8-12, where the first number is N, the second number P, and the third K.

P -

Pedicel - The stalk of a flower: The stalk of a single flower or fruit.
Perennial - A plant living for more than two years: A perennial plant is a plant that has a life cycle of more than two years. From the Latin per, meaning through, and annum meaning year. See our listing of perennial plants.
pH - The acidity or alkalinity of a solution: pH is a scale of 0 to 14 used to describe the acidity or alkalinity of a solution. A pH of 7 is considered neutral and is the pH of pure water. A pH less than 7 represents acidic solutions and more than 7 alkaline. If you're not sure of the pH of your soil, it may be worth purchasing a Soil Testing Kit to accurately asses it.
Photosynthesis - Plant food production: Greatly simplified, it is the process by which a plant makes it’s own food by using sunlight, carbon dioxide and water to make oxygen and sugars.

R -

Rhizome - Underground horizontal stem: Usually underground, a rhizome is a horizontal stem of a plant often sending out roots and shoots from its nodes. Rhizomes are sometimes called creeping rootstalks, or rootstocks. Many plants have rhizomes that spread the plant by vegetative reproduction e.g. Lily of the valley.

S -

Semi-evergreen - Plant type: A plant that retains at least some of it’s foliage during the whole calendar year
Sepal - Flower part: A petal-like structure under the flower petals. Usually green but sometimes modified and colourful.
Spathe - A type of bract: A type of bract, often fleshy and hood like. Example, the yellow spathes of Lysichiton americanus.
Sport - Spontaneous production of unusual plant material: A sport is when a plant produces foliage or a flower that differs in character from the norm. E.g. colour or variegation. The resulting flower or leaf is described as a sport. Many cultivated plants are the result of propagation from sport plant material.
Stamen - Male part of a flower: The Stamen is the male reproductive part of a flower, usually consisting of an Anther and a Filament.

T -

Transpiration - Plant water loss: The process by which a plant loses water from the surface of it’s leaves and stems.
Tuber - A root storage organ: A type of storage organ, storing food for the plant, consisting of a modified root (thickened part of a rhizome), typically high in starch. E.g. Potato.

V -