A
ACID SOIL
A soil which contains now free lime and has a pH or less than 6.5.
ADVENTITIOUS
Term applied to organs produced at a point where such growth would not appear naturally. Roots on an above-ground stem are an example.
AERATION
The loosening of soil by digging or other mechanical means to allow air to pass freely.
ALKALINE SOIL
A soil which has a pH of more than 7.3. Other terms are chalky and limy soil.
ALPINE
A rather vague term used to describe low-growing rockery perennials
ALTERNATE
Leaves or buds which arise first on one side of the stem and then on the other.
ANNUAL
….
ANTHER
The part of the flower which produces pollen. It is the upper section of the stamen.
ASEXUAL
Vegetative reproduction – e.g. cuttings and division.
AWL-SHAPED
A narrow leaf which tapers to a stiff point.
AXIL
The angle between the upper surface of the leaf stalk and sterm that carries it. An axillary bud arises in this angle.
B
BASAL SHOOT
A shoot arising from the neck or crown of the plant.
BASTARD TRENCHING
Another term for double digging.
BEARDED
A petal bearing a tuft or row of long hairs
BEDDING PLANT
A plant which is ‘bedded out’ in quantity to provide a temporary display.
BIENNIAL
Coming soon.
BIGENERIC
A hybrid produced by crossing two different genera – e.g. Heucherella, a hybrid of Heuchera and Tiarella.
BISEXUAL
A flower bearing both male and female reproductive organs – compare dioecious and monoecious.
BLEEDING
The abundant loss of sap from severed plant tissues.
BLIND
Term applied to a mature bulb which produces normal foliage but fails to flower
BLOOM
Two meanings – either a fine powdery coating or a flower.
BOSS
A ring of prominent and decorative stamens.
BOTTOM HEAT
Under surface heat provided in the soil by organic fermentation, electric cables or hot water pipes.
BRACT
A modified leaf at the base of a flower. A cluster of small bracts is a bracteole.
BREAKING BUD
A bud which has started to open.
BUD
A flower bud is the unopened bloom. A growth bud or eye is a condensed shoot.
BULB
…
C
CALCAREOUS
Chalky or limy soil.
CALCIFUGE
A plant which will not thrive in alkaline soil.
CALLUS
The scar tissue which forms at the base of a cutting.
CALYX
The ring of sepals which protect the unopened flower bud.
CAMPANULATE
Bell-shaped
CHELATE
An organic chemical which can supply nutrients to plants in a soil which would normally lock up the plant-feeding element or elements in question.
CHIMAERA
A mutation which produces two kinds of tissue – e.g one or more ‘wild’ coloured petals in a Chrysanthemum.
CHLOROPHYLL
The green pigment found in leaves which is capable of using light-energy to transform carbon dioxide and water into carbohydrates by the process known as photosynthesis.
CHLOROSIS
An abnormal yellowing or blanching of the leaves due to lack of chlorophyll.
CLOCHE
A temporary structure of glass or plastic sheets used to protect and hasten the growth of plants in the open.
CLONE
A group of identical plants produced by vegetative reproduction from a single parent plant.
COMPOSITAE
The Daisy Family , in which each flower bears ‘petals’ which are really florets.
COMPOST
Two meanings – either decomposed vegetable or animal matter for incorporation in the soil or a potting/cutting/seed sowing mixture made from peat (‘soilless compost’) or sterilised soil (‘loam compost’) plus other materials such as sand, chalk and fertilisers.
COMPOUND FLOWER
A flower composed of florets.
COMPOUND LEAF
A leaf composed of two or more leaflets.
CORDATE
Heart-shaped.
CORM
Coming soon.
COROLLA
The ring of petals inside the calyx of the flower.
CORONA
The trumpet produced in certain flowers, e.g Narcissus.
CORYMB
A flat-topped inflorescence in which all the flowers open at approximately the same time.
COTYLEDON
A seed leaf which usually differs in shape from the true leaves which appear later.
CROCK
A piece of broken flower pot used at the bottom of a container to improve drainage.
CROSS
The offspring arising from cross-pollination.
CROWN
The bottom part of a herbaceous plant from which the roots grow downwards and the shoots arise.
CRUCIFERAE
The cabbage or Wallflower Family, in which the flower bears four petals in the shape of a cross.
CULTIVAR
Short for ‘cultivated variety’ – it is a variety which originated in cultivation and not in the wild.
CYME
A flat-topped or domed inflorescence in which the flowers at the centre open first.
D
DEAD-HEADING
The removal of faded flowers.
DECIDUOUS
A plant which loses its leaves at the end of the growing season.
DECUMBENT
A prostrate stem with an ascending tip.
DENTATE
Toothed margin.
DIBBER
A blunt-ended wooden stick used to make holes in the soil for transplants.
DIGITATE LEAF
A leaf composed of finger-like radiating leaflets.
DIOECIOUS
A plant which bears either male or female flowers. Compare monoecious.
DISC (DISK)
The flat central part of a compound flower. It is made up of short, tubular florets.
DORMANT PERIOD
The time when a plant has naturally stopped growing due to low temperatures and short day length.
DOUBLE
A flower with many more than the normal number of petals. When the whole of the bloom appears to be composed of petals it is called ‘fully double’ – a ‘semi-double’ flower is the half-way point between a single bloom and a fully double one.
DRAWN
Term applied to pale and lanky seedlings which have been sown too thickly or grown in shady conditions.
DRILL
A straight and shallow furrow in which seeds are sown.
E
ENTIRE LEAF
An undivided and unserrated leaf.
EVERGREEN
A plant which retains its leaves in a living state during the winter.
EVERLASTING
Flowers with papery petals which retain some or all of their colour when dried for winter decoration.
EYE
Two meanings – a dormant growth bud or the centre of a single or semi-double bloom where the colour of this area is distinctly different from the rest of the flower.
F
FAMILY
A group of related genera.
FEATHERED
A petal on which there are feather-like markings on a ground colour which is distinctly different.
FERTILIZATION
The application of pollen to the stigma to induce the production of seed.
FIBROUS-ROOTED
A root system which contains many thin roots rather than a single tap root.
FILAMENT
The supporting column of the anther. It is the lower part of the stamen.
FIMBRIATE
Frillly-edged
FLORE PLENO
Term applied to double flowers
FLORET
The individual flowers of a compound flower or dense flower-head
FLOWER
The reproductive organ of the plant.
FOLIAR FEED
A fertilizer capable of being sprayed on and absorbed by the leaves.
FORCING
The inducement of flowering before its natural time.
FRIABLE
Term applied to crumbly soil.
FROST POCKET
An area where cold air trapped during winter and in which half hardy plants are in much greater danger.
FRUIT
The seed together with the structure which bears or contains it.
FUNGUS
A primitive form of plant life which is the most common cause of infectious disease – e.g mildews and rusts. Such diseases are controlled or prevented by means of fungicides.
G
GENUS (plural GENERA)
A group of closely-related plants containing one or more species.
GERMINATION
The emergence of the root and shoot from the seed.
GLABROUS
Smooth, hairless.
GLAUCOUS
Covered with a bloom.
GROUND COLOUR
The main or background colour of a petal.
GROUND COVER
An ornamental plant which requires little attention and is used to provide a low-growing and weed-proof carpet between other plants.
H
HALF HARDY
A plant which will only grow outdoors in Britain when the temperature is above freezing point. The term is not precise – some half hardy plants can be left outdoors in winter in mild regions of the country.
HARDENING OFF
The process of gradually acclimatising a plant raised under warm conditions to the environment it will have to withstand outdoors.
HARDY
A plant which will withstand overwintering without protection.
HEELING-IN
The temporary planting of newly-acquired stock pending suitable weather conditions for permanent planting.
HERBACEOUS
A plant which does not form permanent woody stems.
HERMAPHRODITE
See bisexual
HIRSUTE
Covered with stiff or coarse hairs.
HONEYDEW
Sticky, sugary secretion deposited on the leaves and stems by such insects as aphids and whitefly.
HOSE-IN-HOSE
A flower which gives the appearance of one bloom inside the other – e.g Canterbury Bell.
HUMUS
Term popularly (but not correctly) applied to partly decomposed organic matter in the soil. Actually humus is the jelly like end-product which coats the soil particles.
HYBRID
Plants with parents which are genetically distinct. The parent plants may be different species, cultivars, varieties or occasionally genera.
I
IMBRICATE
Closely overlapping.
INFLORESCENCE
The part of the plant bearing the flowers – the flower-head.
INORGANIC
A chemical or fertilizer which is not obtained from a source which is or has been alive.
INSECTICIDE
A chemical used to control insects and other small pests.
INVOLUCRE
A ring of bracts surrounding a flower or cluster of flowers.
J
JOINT
See node.
K
KEEL
Boat-shaped structure formed by the two lower petals of many members of the Leguminosae.
L
LANCEOLATE
Spear-shaped.
LANKY
Spindly growth – a stem with a gaunt and sparse appearance.
LARVA
Immature stage of some insects, popularly known as a caterpillar, maggot or grub.
LATERAL SHOOT
A shoot which arises from the side of a main stem.
LEACHING
The loss of soluble chemicals from the soil due to the downward movement of water.
LEAFLET
One of the parts of a compound leaf.
LEAF MOULD
Peat-like material composed of partially-rotted leaves.
LEGUMINOSAE
The Pea Family. Many have papilionaceous (butterfly-like) flowers – e.g Sweet Pea.
LIGHT
Movable part of a cold frame.
LINEAR
Very narrow with parallel sides.
LOAM
Friable soil which is not obviously clayey nor sandy.
LOBE
Rounded segment which protrudes from the rest of the leaf, petal or other plant organ.
M
MONOCARPIC
A plant which dies after flowering and seeding.
MONOECIOUS
A plant which bears both male and female flowers.
MULCH
A layer of bulky organic matter placed around the stems
MUTATION
A sudden change in the genetic make-up of a plant, leading to a new feature which can be inherited.
N
NECTAR
Sweet substance secreted by some flowers to attract insects.
NEUTRAL SOIL
A soil which is neither acid nor alkaline.
NODE
The point on the stem at which a leaf or bud arises.
NODULE
Swelling on the root of a member of the Leguminosae.
O
OBLONG
Longer than broad, with parallel sides.
OBOVATE
Egg-shaped, with broadest end at the top.
OFFSET
Young plant which arises naturally on the parent plant and is easily separated – e.g bulblet and cormlet.
OPPOSITE
Leaves or buds which are borne in pairs along the stem.
ORGANIC
A chemical or fertilizer which is obtained from a source which is or has been alive.
OVAL
Egg-shaped, with broadest part in the middle. Compare obovate and ovate.
OVARY
The part of the female organ of the flower which contains the ovules.
OVATE
Egg-shaped, with broadest end at the base.
OVULE
The part of the female organ of the flower which turns into a seed after fertilisation.
P
PALMATE
Five or more lobes arising from one point – hand-like
PANICLE
An inflorescence made up of a number of racemes.
PEAT
Plant matter in an arrested state of decay obtained from bogs or heathland.
PEDICEL
The stalk of an individual flower.
PEDUNCLE
The stalk of an inflorescence.
PELTATE LEAF
A leaf in which the stalk is attached to the undersurface and not to an edge – e.g. Nasturtium.
PERENNIAL
….
PERIANTH
The outer organs of a flower – the petals plus the sepals.
PETAL
One of the divisions of the corolla – generally the showy part of the flower.
PETALOID
Term applied to organs which assume the form of petals – e.g stamens in double flowers.
PETIOLE
The leaf stalk
pH
A measure of acidity and alkalinity. Below pH 6.5 is acid, above pH 7.3 is alkaline.
PICOTEE
Term applied to a narrow band of colour on a pale ground at the edge of a petal.
PINCHING OUT
The removal between the finger and thumb of the growing tip of the stem to induce
bushiness or to hasten maturity.
PINNATE LEAF
A leaf with a series of leaflets borne on either side of a central stalk.
PIPING
A cutting obtained by pulling off the tip of a non-flowering shoot – e.g Pinks and Carnations.
PISTIL
The female organ of a flower, consisting of the stigma, style and ovary.
PLUNGE
Term applied to the insertion of a potted plant up to its rim in a bed of peat, sand or ashes.
POLLEN
The yellow dust produced by the anthers. It is the male element which fertilizes the ovule.
POLLINATION
The application of pollen to the stigma of the flower.
PRICKING-OUT
The first planting out of a seeding or rooted cutting into another container or nursery bed.
PROPAGATION
The multiplication of plants.
PROSTRATE
Growing flat on the soil surface : procumbent.
PUBESCENT
Covered with short, downy hairs.
R
RACEME
An unbranched inflorescence which bears flowers on stalks.
RADICAL
Term applied to a leaf which arises at soil level.
RENIFORM
Kidney-shaped.
RETICULATE
Marked with a branched network of veins or fibres.
REVERSION
A sport which has gone back to the colour or growth habit of its parent.
RHIZOME
A horizontally-creeping underground stem which produces shoots and roots.
ROSETTE
Term applied to a whorl of leaves arising at the base of a plant.
RUGOSE
Rough and wrinkled.
RUNNER
A stem which grows along the soil surface, rooting at intervals.
S
SAGITTATE
Arrow-shaped.
SCAPE
A leafless flowering stem.
SCREE
Bed of gravel, peat and soil for growing alpines.
SEED
The reproductive unit of a flowering plant.
SEED LEAF
See cotyledon
SELF-COLOURED
Term applied to a flower of a single uniform colour.
SEPAL
One of the divisions of the calyx.
SERRATE
Saw-edged
SESSILE
Stalkless.
SIMPLE LEAF
A leaf which is not compound.
SINGLE
A flower with no more than the normal number of petals.
SPADIX
A fleshy spike in which small flowers are embedded.
SPATHE
A bract surrounding an inflorescence.
SPATHULATE
Spoon-shaped.
SPECIES
Plants which are genetically similar and which breed true to type from seed.
SPIKE
An unbranched inflorescence which bears stalkless flowers.
SPIT
The depth of the spade blade – about 10 in.
SPORT
A plant which shows a marked and inheritable change from its parent; a mutation.
SPUR
A tube like projection from a flower.
STAMEN
The male organ of a flower, consisting of the anther and filament.
STANDARD
Two meanings – either the large upper petal of Sweet Pea-like flowers or a plant with a tall bare stem and a terminal head of leaves and flowers.
STELLATE
Star-shaped
STIGMA
The part of the female organ of the flower which catches the pollen.
STIPULE
A small outgrowth at the base of the leaf stalk.
STOLON
A runner-like stem which forms roots and produces a new shoot at its tip (not at intervals along its length).
STOOL
The crown of a border perennial used for propagation.
STOPPING
See pinching-out.
STRAIN
A selection of a variety, cultivar of species which is raised from seed.
STRIKE
The successful outcome of taking cuttings – cuttings ‘strike’ whereas grafts ‘take’.
STYLE
The part of the female organ of the flower which connects the stigma to the ovary.
SUBSOIL
Soil below the fertile top layer.
SUCCULENT
A plant with fleshy leaves and/or stems adapted to growing under dry conditions.
SYNONYM
An alternative plant name.
SYSTEMIC
A pesticide which goes inside the plant and travels in the sap stream.
T
TENDRIL
A modified stem or leaf which can wind around a support.
TERMINAL
Term applied to organs borne at the tip of a stem.
THROAT
The tube formed by the corolla of some flowers.
TILTH
The crumbly structure of soil at the surface.
TOMENTOSE
Densely covered with fine hairs.
TRANSPIRATION
The loss of water from the surface of the leaves and stems.
TRANSPLANTING
The movement of a plant from one site to another.
TRUSS
A flower-head or tightly packed inflorescence.
TUBER
…..
TUNIC
A dry and often papery covering of corms and some bulbs.
U
UMBEL
An inflorescence in which all the flower stalks are of similar length and arise from the same point.
UNISEXUAL
A flower of one sex only – see monoecious and dioecious.
V
VARIEGATED
Leaves which are spotted, blotched or edged with a colour which is different to the basic one.
VARIETY
Strictly speaking, a naturally occurring variation of a species – see cultivar.
VEGETATIVE REPRODUCTION
Division , cuttings, grafting and layering as distinct from sexual reproduction by seeds.
VIRUS
An organism which is too small to be seen through a microscope and which is capable of causing malformation or discoloration of a plant.
W
WEED
A plant growing in the wrong place.
WHORL
Leaves, petals or branches arranged in a ring.