Glossary of Gardening Terms A-L

Glossary of Gardening Terms and Words

Also See: Glossary of Gardening Terms M-Z


Acid soil

Such soils have a pH of less than 6.6. Acidity can check the growth of some plants and few of them will grow in a very acid soil. It can be corrected by the addition of lime, but the overuse of lime can be disastrous, taking up to 15 years to correct. Peat soils are acidic. (See also soil testing.)

Alkaline soil

Such soils have a pH of 7 or over. They are chalky soils, that is, they contain carbonate of lime in the form of chalk. It is difficult to correct this type of soil as rain washes more lime into the soil from the underlying chalk. Adding peat, leafmould or grass cuttings will gradually make the soil more acidic, but the process takes a long time Alkaline soils tend to suffer from a lack of nitrogen and potassium, both of which are essential to healthy plant growth. (See also soil testing.)


A plant which germinates, flowers, produces seeds and dies within a year. Examples are Alyssum maritimum, Centaurea cyanus (cornflower) and Malcolmia maritima (Virginian stock).

Bedding out

A term used for setting out bedding plants, hardy or half-hardy annuals, biennials or perennials which are used for display during the summer. They can usually be bought ready for bedding out from a nursery. Bang the sides of the container to loosen the soil and ease the plants gently out. Separate them carefully so that each plant has a good root with soil attached. Use a trowel to dig a hole which is big enough for the plant’s root ball, put in the plant and replace the soil slightly above the level of the original soil. Firm down well and water.


A plant which has a life cycle spread over two years. During the first year the plant produces leafy growth; during the second year, it produces flowers and seeds, then dies. Examples are Dianthus barbatus (sweet william), Lunaria annua (honesty) and Oenothera trichocalyx (evening primrose). Some perennials are treated as biennials, for example Cheiranthus cheiri (wallflower).


This process keeps light away from plants such as celery and chicory, so that the leaves or stems do not form chlorophyll and are less bitter to eat. The plant to be blanched can be earthed up, wrapped in newspaper or covered over with a flower pot.


Plants are said to have ‘bolted’ when they run prematurely to seed. Spinach, lettuce and beetroot are especially prone to this during periods of drought. Plants may also bolt as a result of being grown on soil that is in poor condition.


A way of scattering seeds widely over an irregular patch, rather than sowing them in straight lines or drills. Lawn seed is usually broadcast.


The outer green part of a flower, where sepals have joined together to form a bowl, or funnel, out of which the petals grow.


A dry fruit which usually contains loose seeds.

Catch crop

A catch crop is a quick-growing vegetable such as lettuce or radish, that is grown between rows of slower growing crops, or is grown in the space from which one main crop has been harvested before a second main crop is planted.


The loss of green colouring (chlorophyll) in a leaf, which makes it look bleached or yellowish. In extreme cases, the plant may the It is sometimes caused by a virus, but is usually due to a lack of essential minerals in the soil.


A clamp can be used to store root crops such as potatoes or turnips outdoors. Remove any soil adhering to the roots and heap them up in a ridge shape on a bed of straw about 6in (150mm) thick. Cover the heap with a 6in (150mm) layer of straw. Cover the layer of straw with some soil to keep it in place and leave the heap for 24 hours. After 24 hours dig a drainage trench around the heap. Use the soil removed from this trench to cover the straw with a 6in (150mm) layer of soil. Ensure that the soil covering the clamp is smooth by beating it flat with a spade, which will enable the clamp to shed rain. Ventilation holes should be left at 36in (915mm) intervals along the top of the clamp. Pull up tufts of straw through the soil layer to keep the ventilation holes open. Inspect the stored roots that you can see each time you open the clamp and remove any rotten ones. If you discover many rotten ones you must remake the clamp.


The descendants of a plant that has been propagated solely by vegetative means. Many clones are sterile, but even if the plants set seed, the offspring would not be regarded as part of the clone.


Either a manure substitute produced from rotting vegetable waste, or a specialized soil mixture used for raising seedlings and potting on houseplants.


Usually applied to a specially trained and pruned apple or pear tree which bears fruit on a single main stem. Diagonal cordons can be trained on wires to form a decorative and productive hedge.


The swollen underground stem of flowers such as crocus or gladiolus. After flowering the old corm withers while a new one grows on top of it.


The ring of petals in the flower as a whole.


The trumpet- or cup-shaped part of the flower which lies between the petals and the stamens.


The first seedling leaf or leaves to appear at germination. These leaves are frequently different in shape from the plants’ adult leaves. (See also Dicotyledon; Monocotyledon.)


These are broken pieces of a clay pot which are placed over the drainage hole of a container.

Crop Rotation

In agriculture crop rotation is used to minimize the problem of soil-borne diseases. These are usually specific to one plant or at least to one family of plants and if this plant is not grown on the same ground for some four years there is a good chance that the disease will die out. Unfortunately with rather small areas such as the normal vegetable plot the distances between the various crops are so small, that the disease can more easily travel from one part of the plot to another. What this means is that if you get a really pestilential infection, such as club root in brassicas, growing your brassicas in a different part of the garden will probably not be effective and the only sure method of eliminating this disease will be to avoid growing brassicas for several years. Even so it is usually inadvisable to grow the same sort of vegetable in the same place two years in succession. Many people seem to grow runner beans on the same ground year after year without any deterioration in the crop and many growers once they have made a well-established onion bed, continue to grow onions on it until there are signs of deterioration.

Root vegetables may well get split roots if grown on freshly-manured ground, which brassicas will enjoy, so it is advantageous to use your manure where you hope to grow brassicas and grow root crops on this ground the following year. Pulse crops, ie. peas and beans, put nitrogen into the soil, so that they can usefully follow the root crops, which can be followed by salad crops or by onions if no separate onion bed has been made.


The base of an herbaceous perennial, for example rhubarb, from which both shoots and roots grow.


A variant of a plant, either species or hybrid, which has arisen in cultivation and is not known in the wild. Wild variants are known either as varietas, (abbreviated var.) or forma, (abreviated f.) The latter are given Latin names, while cultivars (abbreviated cv.) are given names in the language of the country in which they were raised.


A tree or shrub that loses its leaves at the end of each growing season.


Plants in this group have two seed leaves (see Cotyledon above).


digging Digging is essential to the creation of a fertile soil.

It should be carried out in autumn so that the soil can be broken down by frost and rain during the winter. The process aerates the soil and manure or compost can be incorporated at the same time.

There are two types of digging; single digging which consists of turning over the top spit of soil and double digging which consists of turning over the soil to a depth of two spits. Double digging should be used on soil that has been neglected for a long time, or which is badly aerated.


To remove a certain number of secondary flower buds below the main one, so that this will develop into a bigger flower. Carnations, chrysanthemums, roses and dahlias can all be disbudded.

Disk ( Disc) Floret

see Floret below

Double Flowers

Abnormal flowers in which the stamens and/or pistils have been transformed into petals. Fully double flowers are, therefore, completely sterile, but some double flowers still have a few stamens and often undamaged pistils, from which seed can be raised. In semi-double flowers only a few of the sexual organs have become petaloid. Plants of the daisy family with all ray florets are often termed double, but this is inaccurate; there is no such thing as a single dandelion, for example.


A plant which is growing in a group that is too closely packed or in a poorly lighted position is inclined to become long and thin and is often pallid in colour. Such a plant is said to be ‘drawn’.


A straight, shallow U or V-shaped furrow in which seeds are sown. The easiest way to make a drill is with a rake or hoe.


A type of specially trained fruit tree that is grown flat against wires or a wall, with horizontal branches leading out in pairs from the main stem.


A plant is said to be ‘etiolated’ when lack of light draws it up into lanky, pallid growth. Young seedlings are especially prone to this if they are not given maximum light as they are growing.


A tree or shrub which bears foliage throughout the year.


A hybrid plant which is the first generation of a controlled crossing of parent plants. Seeds from F1 hybrids do not come true and so the crossing has to be repeated to reproduce the original hybrid.


A hybrid plant which is the second generation of a controlled crossing of parent plants.


This refers to a tall, thin habit of growth, especially in trees, such as the Lombardy poplar or the Irish yew.


Some plants and trees will set seed when fertilized with their own pollen. Such plants are called ‘self-fertile’. Others, referred to as ‘self-sterile’, need cross-pollinating with different varieties in order to produce fruit and seed.


An individual flower which forms part of a large flowerhead or inflorescence. Disk florets are tubular, petal-less florets found in many plants of the daisy family. Sometimes they are surrounded by the more conspicuous ray florets, as in the common daisy. Groundsel is composed entirely of disk florets, while some chrysanthemums are composed entirely of ray florets.


Applied to plants which are encouraged to come into growth before their natural time. Hyacinths and some narcissus are forced by keeping in darkness the pots in which they are planted. Tall bell-shaped earthenware pots are used to force rhubarb into early growth.


A soil which is crumbly and therefore can be easily worked.


A chemical used for killing fungal diseases.


A division of a plant family which is based on the plant’s botanical characteristics. A plant’s genus is indicated by its first botanical name. For example, cornflower belongs to the genus Centaurea. The plural form of genus is genera.


The first stage in the development of a plant from a seed.

Ground Cover

Plants referred to as ‘ground cover plants’ are used to cover the soil, usually under trees or between shrubs. Besides bringing colour to the planting scheme they provide a dense weedproof cover. Hypericum calycinum (St John’s wort) is an excellent ground cover plant.

Growing medium

see Compost above


This refers to plants from tropical and sub-tropical regions which require protection during the winter when grown in temperate climates. It may also refer to certain shrubs and herbaceous perennials which will survive average — but not severe — winters out of doors if grown in sheltered positions or in regions which have a mild climate. (See also Hardy.)

Hardening Off

This is the method adopted to accustom plants to a cooler environment than the one in which they germinated. For example, plants that are germinated in a greenhouse are hardened off by being placed in a cold frame during late spring. The lights of the frame are raised further each day to allow more air in until they are completely removed. The plants can then be transferred to their permanent position. (See also Frame.)


This refers to plants which are capable of surviving, indeed thriving, under the natural environment given to them. (See also Half-hardy.)


To make a rough trench in which plants can be laid and their roots covered with soil until the permanent planting place is ready.


A plant which does not form a woody stem, remaining soft and green throughout its life. The term is used to refer to annuals, biennials and perennials. Such plants die down to the ground each winter.


A chemical used for killing weeds.


Decayed organic material : animal manure, compost, leaves, etc. are all sources of humus which is a vital element in a fertile soil.


A new plant which is the offspring of two different species. This is usually indicated by an x between the botanical names of the parent plants. For example; Viola x wittrockiana (pansy). (See also: F2 above.)


A chemical compound or fertilizer which does not contain carbon.


A chemical compound that destroys garden pests.


Lime is useful for increasing the fertility of soil generally and improving the texture of clay soil as it makes the tiny clay particles clump together.

Hydrated lime should be applied at a rate of 3oz to the square yard (75g to the square metre). If ground limestone is used it should be applied at the rate of 6oz to the square yard (150g to the square metre) Lime should be applied during the late autumn and winter, ie. between October and February. It must never be applied at the same time as other fertilizers or manure as it reacts chemically with them or prevents them from acting by making them less soluble. NOTE: Lime should never be given to ericaceous plants such as heathers, azaleas or rhododendrons.


Also See: Glossary of Gardening Terms M-Z

14. May 2011 by Dave Pinkney
Categories: Glossary | Tags: , , , , , | Comments Off on Glossary of Gardening Terms A-L


Get every new post delivered to your Inbox

Join other followers: