Abiotic – A non-living occurrence that could cause problems. Examples, air pollution and salt.

 

Abscisic acid – A plant hormone that promotes dormancy in buds and seeds.

 

Acclimation – The process of adapting plants to a new environment which could be of particular importance to new plants.

 

Acid soil - Soil with a pH below 7

​

Acidic Loving Plants – Plants that require a PH level below 7 to reach their best. Soil amendments like sulfur might need to be added.

 

Adaptation – Plant characteristics that allow it to grow in a particular condition. Zonal considerations. Some plants might be adaptable as houseplants i.e. they can grow indoors during winter.

​

Aeration - Puncturing the soil to allow better water and air circulation

​

Annual - A plant that completes its entire life cycle (growth, reproduction, death) in one season. Annuals are often a great summer addition of colour to a perennial garden.

​

Anther – Terminal part of the stamen (male) where pollen is produced.

 

Apex – Tip or terminal. Important to look for especially in tree health.

 

Apical bud dominance – Healthy terminal apical bud dominance will supress excessive side (lateral) bud growth.

 

Auxin – An essential plant hormone that controls plant growth.

 

Axil – Where a leaf stalk or leaf joins the stem.

​

Bacteria – Single cell organisms that often cause plant and animal disease.

​

Bareroot - These plants have been field-grown and are supplied in a dormant state with the soil removed.  For example, Roses often come bareroot

​

Bark – The exterior part of a woody trunk consisting of mostly dead matter. Protects the cambium.

​

Biennial - A plant that completes its entire life cycle in two years, growing in the first year and reproducing and dying in the second.

​

Blanching - Keeping light from tender vegetable stems.

​

Blight – A plant disease that kills leaves, flowers and stems.

​

Bolting - To flower and produce seed prematurely.

​

Bone meal - A slow-release phosphorous rich natural fertilizer.

​

Bonsai - The Japanese method of training dwarf plants in containers.

​

Botanical name - The scientific name for a plant; plants may have several common names.

​

Bract – Modified leaf that are colorful. Example, dogwood and poinsettias.

 

Brambles – Plants with cane shoot growth. Example, raspberries and blackberries.

 

Broadleaf evergreen – A shrub or tree with green leaves (as opposed to needles) that hold their foliage all year long. Example, Euonymus

 

Bud - The swelling as a plant starts new flower or leaf growth.

​

Bud union - Refers to the point at which the plant has been grafted on to a rootstock and is usually found at soil level. This is the result of a technique called ‘budding’ where the bud of one plant is grafted on to another plant.

​

Bulb - An underground storage organ with fleshy scale leaves from which the plant flowers and grows before becoming dormant. Such as Daffodils, tulips etc.

​

Bulblet - A small bulb developing at the base of a mature one.

​

Cactus - A succulent plant with swollen, fleshy stems, and needles.

​

Callus – Corky tissue to protect wounded woody plants.

 

Calyx – Comprises the sepals, which covers and protects the petals as they develop.

​

Cambium – A thin tissue layer that provides cells for plant growth. It is found between the xylem and phloem. If it becomes severely damaged the plant will probably die.

 

Canker – Open wound stem, branch or trunk injury that becomes infected with fungal or bacterial pathogens.

​

Cane - The stems of a raspberry or blackberry plant. Raspberry plants are supplied as dormant canes.

​

Catkin – Drooping flower clusters. Examples, oak, willow, birch.

​

Chitting - Placing seed potatoes in a tray or egg box in a bright, cool but frost-free place to encourage them to sprout prior to planting.

​

Chlorophyll – The pigment that gives plants green coloration.

 

Chlorosis – A yellowing of leaf tissue due to the lack of chlorophyll. Iron or magnesium additives are used to treat symptoms.

​

Cloche - Structure made of glass, plastic or horticultural fleece placed over a plant for protection or for forcing early crops.

​

Cold Frame - Unheated frame for growing on and acclimatizing hardy and half-hardy plants outdoors.

​

Compaction – Soil pressure that prevents water and air flow.

 

Companion crops – Two non-competitive crops grown at the same time in the same area.

 

Compost – A mix of soil and decomposing organic matter.

 

Compound leaf – A leaf blade divided into two or more distinct leaflets. Example, roses.

 

Conifer – A plant that bears cones.

 

Cordon - A plant carefully trained to grow as one main stem, or occasionally two or three main stems, by removing side-shoots. Such as Tomato Plant.

​

Corm - A rounded underground storage organ, consisting of the stem base, and often with a fibrous outer layer. It is replaced by the plant annually. An Example is Begonias, crocus and gladioli.

​

Cotyledon – Significant part of the embryo serving as a seed food storage structure.

​

Crown - The growing point of a plant from which new shoots emerge, at or just below the soil surface. Such as asparagus.

​

Cross pollination – The transfer of pollen from one plant to another: from anther to stigma.

​

Cultivar - A plant that is bred or selected by growers for unique flowers, leaf colour, growing habit etc. It has distinct and uniform characteristics that differ from the original species.

​

Cutting – Production of a new plant from a cutting.

 

Cytokinin – An essential plant hormone promoting cell division.

​

Damping off – Seedling disease causing decay prior to germination.

​

Dead-Head - To remove the spent blooms on a plant to encourage further flowering or to prevent self-seeding.

​

Deciduous - A plant that sheds its leaves each year.

​

Desiccation – Drying out and dying of plant tissue.

 

Dicot – Two cotyledons present in the seed.

 

Dioecious – Where male and female flowers are found on separate plants. A male and female plant are required for pollination. An example is ginkgo.

​

Direct Sow - To sow seeds outdoors in their final positions, where you would like them to flower or crop.

​

Division - The process of dividing clump forming plants into separate smaller plants.

​

Drip zone -The area around a tree where water drops from the canopy. This is a useful area for root feeding.

​

Dormancy - The annual period when plant's growth slows greatly, usually the winter.

​

Dwarf - A miniature form of a particular plant.

​

Earth up - To draw soil up around a plant to exclude light, protect from frost or encourage roots to develop from the stem.

​

Embryo – Developing plant inside the seed.

 

Epiphyte – A nonparasitic plant that draws nutrients from the air and usually grows on another plant. Example, orchids.

​

Espalier – Training to grow trees or shrubs on a trellis or wall.

​

Ericaceous – Term used to describe plants that like acid soil and will not tolerate alkaline soils (containing lime or chalk), such as blueberries.

​

Etiolation – Where lack of sufficient light induces weak growth, elongated pale stems with under-developed leaves.

 

Eukaryotic organism – The earliest formed microfossils that posses a clearly defined nucleus.

​

Everbearing - Refers to strawberry varieties that yield a small crop in early summer, a few berries throughout the rest of the summer, and another heavier crop during late summer and early autumn.

​

Evergreen - A plant that retains its foliage all year long

​

Exotic – A plant not native to a particular region.

​

F-1 Hybrid – Is the term for a first-generation offspring derived from breeding two distinct pure-bred lines. They are vigorous and uniform plants. Seeds produced from F1 Hybrid will not be true to their parents.

​

Feathered Maiden - A one-year old tree with several side branches (feathers).

​

Fertilizer - A compound that provides plants with nutrients.

​

Fibrous roots – Heavily branched roots with no taproot development.

​

Filament – a thread like structure. or slender stalk the bears the anther (where pollen develops).

 

Floret – A small flower that is part of a larger flower. Example, sunflower – the florets develop individually. Broccoli is another example.

 

Flower – The seed bearing part of a plant.

​

Floricane - Refers to raspberry and blackberry stems that grow for one year before bearing fruit and flowers e.g. summer-fruiting raspberries and blackberries. This canes are replaced by new growth each fall, and the old cane should be pruned down.

​

Foliage - A term describing plant leaves.

​

Foliar feeding – Applying, usually by spray, fertilizer to plant leaves.

​

Force - To encourage a plant to come into stem, leaf and flower production out of season.

​

Frost line – The depth at which soil groundwater freezes.

 

Fruit – The ripened plant ovary which contains seeds.

 

Fruiting habit – Describes the way in which fruit forms and grows on woody plants.

 

Fungicide – Pesticides that kill and prevent fungi and their spores.

 

Fungus – Eukaryotic organisms that lack chlorophyll – often a cause of plant disease.

 

Furrow - A shallow trench in which seeds or seedlings are planted.

​

Gall – Pathogen or pest induced swelling and outgrowth.

 

Genus – Taxonomic rank used in biological classification.

 

Germination - Refers to the point at which a seed undergoes physical changes and begins to grow.

​

Gibberellin – An important plant hormone that promotes internode elongation and cell enlargement.

 

Girdling – The removing of woody material inward to the cambium. Also known as ring-barking. It can ultimately kill the plant.

​

Grafting - Where one plant is artificially joined to the rootstock of another, so they eventually function as one plant.

​

Graft union – The point where grafted plants join together. Also called a bud union.

​

Ground cover - Low growing, spreading plants that cover large areas

​

Gymnosperm – Seed producing plants frequently in the form of cones. The seeds are exposed. Examples include; conifers, cycads and Ginkgo.

​

Hardiness - A plant's ability to survive in harsh conditions.

​

Half hardy annual - A plant that completes its entire life cycle (growth, reproduction, death) in one season. Can be grown outdoors but requires winter protection from frosts and temperatures below 0C.

​

Half hardy biennial - A plant that completes its entire life cycle in two years, growing in the first year and reproducing and dying in the second. Can be grown outdoors but requires winter protection from frosts and temperatures below 0C.

​

Half hardy bulb/corm/rhizome/tuber - Plant that grows from an underground storage organ. Generally supplied in a dormant condition with no top growth. Can be grown outdoors but requires winter protection from frosts and temperatures below 0C.

​

Half hardy perennial - A plant that lives for more than two years. Can be grown outdoors but requires winter protection from frosts and temperatures below 0C.

​

Half hardy tree/shrub - Woody plant, usually having a permanent framework of branches. Can be grown outdoors but requires winter protection from frosts and temperatures below 0C.

​

Harden off - To acclimate young plants that are growing in a protective environment, to cooler conditions outdoors. This is normally achieved by leaving plants outside during the day and bringing them undercover at night.

​

Hardy annual - A plant that completes its entire life cycle (growth, reproduction, death) in one season. Capable of withstanding outdoor winter temperatures down to -15C.

​

Hardy biennial - A plant that completes its entire life cycle in two years, growing in the first year and reproducing and dying in the second. Capable of withstanding outdoor winter temperatures down to -15C.

​

Hardy bulb/corm/rhizome/tuber - Plant that grows from an underground storage organ. Generally supplied in a dormant condition with no top growth. Capable of withstanding outdoor winter temperatures down to -15C.

​

Hardy perennial - A plant that lives for more than two years. Capable of withstanding outdoor winter temperatures down to -15C.

​

Hardy tree/shrub - Woody plant, usually having a permanent framework of branches. Capable of withstanding outdoor winter temperatures down to -15C.

​

Heartwood – Older, dead, central wood of trees that no longer transports water and nutrients. It is commonly darker in color.

 

Healing in – A process to temporarily store plants before permanent planting. Usually by digging a shallow trench and covering the roots with soil.

​

Herb - Plants with culinary or medicinal uses

​

Herbaceous plant - A non-woody perennial plant, often dying back in the winter and becoming dormant by means of underground rootstocks or a woody base. Growth resumes in the spring.

​

Herbicide - A chemical used to kill unwanted plants

​

Hormone – Essential chemicals produced by plants that regulate most life cycle aspects – growth, development, reproduction, and longevity.

 

Horticulture – The art, science, technology, and business of plant cultivation.

 

Humidity – The concentration of water vapor in the air.

 

Humus - Organic matter resulting from composting

​

Hybrid - A plant variety resulting from the combination of two different plant species, varieties, or cultivars.

​

Hydroponics – A horticultural practice that grows plants without using soil.

 

Imperfect flower – A flower containing only the male or female reproductive organs, but never both. Example, most grasses, squash,sweet corn, cucumber.

 

Incomplete flower – A flower missing any of it’s natural form parts, which could be, the petals, sepals, stamen or pistils.

 

Indigenous – Native to a particular region or area.

 

Infectious – Spreading and transmitted, such as infectious disease by bacteria, virus, fungi or parasite.

 

Inflorescence – Describes the various arrangement of flowers on a plant.

 

Insecticide – Substances (either chemical or organic) used to kill and repel unwanted insects.

 

Integrated Pest Management (IPM) – Effective and environmentally sensitive pest management practice.

 

Internode – The portion of a stem between nodes.

 

Invasive – A species that is not native to a particular area and can cause harm to the native environment.

 

Juglone – A chemical primarily produced in the roots of black walnut trees which is toxic to many plants. Juglone is often the cause of surrounding perennial plant death.

 

Landscaping – The practice and art of designing and implementing outdoor spaces.  The process usually starts with a landscape design that maps our the type number and best light and soil locations for plants about to be placed.

 

Larva – The active immature stage of insect development.

 

Latent bud – An inactive bud ready to grow if stimulated by the right conditions.

 

Lateral meristem – The vascular and cork cambium. Cell division in the vascular meristem results in increased plant girth.

 

Layering – An asexual plant propagation technique. The new plant is temporarily attached to a mother plant while it forms roots. Natural layering is where a branch touches the soil and forms new adventitious roots.

 

Leaching – The draining away of nutrients in the soil. This is applicable to potted plants as well, requiring the need for regular fertilizing to achieve optimum plant growth.

 

Leader - The plant's main stem

Leaf mold – Produced by decomposing leaves as they break down into organic compost.

 

Leggy – Long spindly growth often because of insufficient light.

 

Legume – Seed pod. Examples, beans, peas, lentils.

 

Lenticel – Pores in a woody stem that allow for the exchange of gas between the plant and atmosphere.

​

Lime - Calcium compounds, often applied to lower the pH of the soil (make it more alkaline); particularly useful when growing brassicas (cabbages, broccoli etc.) to prevent club root disease.

​

Loam - Soil rich in organic material, ideal for growing

​

Long canes - These are raspberry canes  which are supplied at a more mature stage of their life and will produce fruit in their first season. The canes supplied are longer than usual.

​

Macro-nutrient – The most important required for good plant growth are; nitrogen, phosphorus, and potassium.

​

Maiden tree – Is a young tree, generally less than a year old, that can be trained into any form required.

​

Manure – Animal dung. An organic soil fertilizer and enhancer.

 

Meristem – Plant tissue where cells actively divide.

 

Metamorphosis – The process of insect transformation from immature to adult form.

 

Microbe – A microorganism.

 

Microclimate - The climate of a small area. Yards may contain several microclimates that may support the needs of different plants.

​

Monocot – A single cotyledon present in the seed. Example, grass.

 

Monoecious – Has both male and female flowers on the same plant.

 

Mosaic – A viral infection characterized by leaves mottled with yellow, white and green spots. Being a plant virus, there is no cure, and best practice would be to remove and destroy infected plants.

​

Mulch - Layer of material placed on the soil and around plants to retain moisture, suppress weeds and improve soil structure. Materials used for mulching include well-rotted manure, compost, polythene sheets or gravel.

​

Mycelium – Mass of branching thread-like hyphae that make up the vegetative body of fungi.

 

Mycorrhiza – Fungi that has a symbiotic (mutually beneficial) relationship with plant roots.

​

Native – A plant that grows naturally and is indigenous to a region.

​

Naturalizing - The process of planting bulbous plants where they are scattered to create a natural look.

​

Naturalizing – Bulbs, once planted, that are left and return year-after-year.

​

Necrosis – Death of plant tissue.

 

Nematode – Microscopic wormlike organisms that could cause plant disease.

 

Nitrogen - The element presents in fertilizer that promotes leaf growth.

​

Node – Location on a stem to which a leaf or branch is attached. Most pruning should be done just above a node.

 

Nose – Bulb tip.

 

Nymph – Immature stage of insects.

 

Offset – Sometimes called a pup. Many plants produce offsets which will grow to be virtually identical to the mother plant. Example, bromeliads, cacti.

 

Open center pruning – Eliminates the central trunk to encourage lateral growth. Particularly used on fruit bearing trees.

 

Organic gardening - Gardening without the use of pesticides.

​

Organic matter - Substance of animal or plant origin – such as compost, leaf mold or manure. Useful for improving soil structure and supplying nutrients to plants.

​

Overwinter – Caring for plants in a condition that will let them survive winter and dormancy.

​

Panicle – A branched raceme bearing more than one flower. Example, astilbe.

 

Parasite – A pest living off the host plant to the detriment of the plant.

 

Parthenocarpy – Production of fruit without pollination. Examples, pineapple, banana, watermelon. Seedless varieties are developed by parthenocarpy.

 

Pathogen – A broad term of the organism that causes plant disease. Examples, fungi, bacteria, nematodes.

 

Peat moss – The production of a growing medium from sphagnum moss. It’s low PH (acidic) level makes it a suitable amendment for plants like blueberries and azaleas. Peat has virtually zero organic fertilizer value. The sale of peat moss to gardeners will be banned in 2024 in the UK to help alleviate the further destruction of peatland. While not banned elsewhere it is encouraged that gardeners to go peat-free. Wood fiber, coco coir, and bark are all great substitutes, while also being more eco-friendly.

 

Pedicel – Stalk bearing an individual flower.

 

Peduncle – Flower stalk.

​

Perennial - A plant that lives for more than two years.

​

Perfect flower – Both male and female reproductive structures are present.

 

Perlite – Organic volcanic material that improves aeration, water retention and drainage when used as a soil additive.

 

Pesticide – Substances used to control pests.

 

Petal – Parts of the flower that are often prominently colored.

 

Petiole – Stalk that joins to a leaf stem.

 

PH – The measure of acidity or alkalinity. On a scale of 1 to 14, 7 is neutral, below 7 is acidic, above 7 is alkaline.

 

Phloem – Vascular tissue that carries food to the leaves and roots. Located on the outer side of the cambium.

 

Phosphorous - The element of fertilizer that promotes root growth.

​

Photoperiodism – The response of plants to light exposure. Long day plants require more light exposure than short day.

plants. Day neutral plants require equal light and dark exposure.

 

Photosynthesis – The process by which green plants use sunlight to synthesize foods from carbon dioxide and water.

 

Phototropism – Plant movement in response to light.

 

Phytoplasma – A bacteria that infects many plants and crops.

 

Pinching - Removing the growing points of a young plant to encourage side-shoots to form. This encourages a bushy habit and more flowering stems.

​

Pistil – Female reproductive parts of a flower comprising the ovary, stigma and style.

 

Pith – The oldest part of a tree located at the center of the trunk.

 

Pollen – Minute grains produced by the male part of the flower that causes the female part to produce seeds.

​

Pollination - The transfer of pollen between flowers, which can be carried out by the wind, insects, animals or by hand.

​

Post-emergent herbicide – Applied directly to green tissue to kill or inhibit plant growth.

 

Pre-emergent herbicide – applied to the soil before green tissue is present to kill or inhibit plant growth.

 

Potassium - The element of fertilizer that promotes cell strength and plant hardiness.

​

Potting soil - A mix of soil or other products used for plants grown in containers.

​

Pot on - To remove a plant from its container (normally when it has outgrown the space) and place it into a new container for further growth.

​

Pot up - To place seedlings and cuttings into containers to grow on.

​

Prick out - To remove and transfer seedlings into pots or module trays to give them more space to grow.

​

Prickle – A sharp thorn like growth which develops on the bark. Example, roses, cacti, blackberry, raspberry.

 

Primary growth – Growth from the apical meristem.

​

Propagate-To grow plants from seed or by vegetative means e.g. cuttings or grafting.

​

Pruning - The removal or shortening of branches from plants

​

Raceme – A flower cluster with the separate flowers attached by short equal stems.

 

Radicle – First part of the seedling to emerge from the seed.

 

Resistance – The ability of plants to combat pathogens. Developing disease resistant plants is a prominent part of modern horticulture.

 

Respiration – The absorption of oxygen molecules to produce water, carbon dioxide and energy.

 

Rhizome – A modified stem that send out shoots and roots from its nodes. Examples, canna lilies, bearded iris, ginger.

 

Roguing – Removal of inferior and diseased plants.

 

Root - The underground part of the plant that supplies nutrients and water to the plant from the surrounding soil.

​

Root ball - The roots along with the soil that clings to them.

​

Root hairs – Cylindrical root extensions used to absorb food and water.

​

Rooting hormone - A liquid or powder that contains hormones which stimulate root formation in cuttings.

​

Root rot – Tissue decay mostly due to excessive water.

 

Rootstock – The root system and part of a tree where another tree (the scion) is grafted on. Very common on fruit trees and roses.

 

Runner - A trailing stem growing above ground and rooting at the nodes, where plantlets are produced for example strawberries are runner grown.

​