PELARGONIUM Geranium cultivation techniques

This plant, with its bright heads of white, pink, red or purple flowers is found in gardens, greenhouses, window boxes, balconies and window sills everywhere. The Geranium is one of our favourite summer bedding plants, but it is not really a Geranium at all – it is the Zonal Pelargonium.

Look at one of the leaves of a typical variety and you will find a horseshoe markingor’zone’-that is wherethenamecomes from. These Zonal Pelargoniums are classified into three groups with somewhat indistinct dividing lines. The most popular ones belong to the Bedding Geranium group which flourish outdoors as well as under glass – the leaves are usually (but not always) zoned. The second group, the Greenhouse Geraniums, have a similar range of flowers and leaf markings but are disappointing outdoors. The Fancyleaf Geraniums make up the final group – here the leaf marking and colouring is more decorative than the blooms, which are generally (but not always) insignificant.

One of the great attractions of Pelargoniums to the enthusiast is the vast range of varieties which are available, and each year new types appear. Indoors the Zonal Pelargonium can be madeto bloom at any time of the year provided that the temperature is at least 50°F and the light is bright enough. With care you can have specimens in bloom in the greenhouse for nine months or even longer each year.

The universally popular Zonal types have an aristocratic relation – the Regal or Show Pelargonium. These are the beauties of the Pelargonium world with their shrubby growth, saw-edged leaves and large, bi-coloured ruffled flowers. But they do have problems-they will only succeed in a warm and sheltered spot outdoors and are best grown as indoor plants. The old varieties have a short

Flowering period: of two or three months, but the modern hybrids can be made to flower all the year round as long as there is sufficient light and warmth.

Another relative is the Ivyleaf Pelargonium, bearing fleshy leaves on trailing stems. In Britain it is used for hanging baskets, tubs and clothing trellis work, but in many other countries it is widely used for ground cover.

You don’t need green fingers to succeed with Pelargoniums. They have few pests or diseases and even fewer fussy demands. All they need is plenty of light and a free-draining soil. Propagation is easy – striking late summer, cuttings is the traditional method but the introduction of the F1 hybrid seed-raised varieties means that you can now produce Zonal Geraniumsforyourgarden aseasily as French Marigolds and Snapdragons.

The old favourites like ‘Paul Crampel’ still dominate the gardens of Britain, but there are now many types from which you can choose. There are Dwarfs which reach only 8 in. There are Stellars, Irenes, Rosebuds, Deacons and soon…. Miniatures growing less than 5 in. and Standards towering to 6 ft or more. Yet the Pelargonium is never truly at home in Britain. It must be lifted from the garden before the first frosts and allowed to sleep indoors until the end of May. Only in particularly favoured spots such as the Isles of Scilly can it grow outdoors as a perennial, and in a wet summer it produces an abundance of leaves and a paucity of flowers.

In the dry and frost-free areas of southern Europe the Pelargonium comes into its full glory. Here the Ivyleaf varieties can be seen cascading from balconies as shrubby perennials and on the hillsides the Zonal Pelargonium has become naturalised in an environment which reminds it of its native South Africa.


Flowers Vi-1 in. across.

While, pink, salmon, red, purple

Rounded leaves; nearly all varieties having a horseshoe marking or’zone’




FANCYLEAF CSI-:HANIUM ‘Mrs Henry Cox’ A Happy Thought Mrs Pollock’



Flowers 1.5-2 in. across

Frilled -white, pink, salmon, red, purple usually marked with darker colour

Flowers Vt -1 in. across

White, pink, red – single or double

Serrated leaves

P. domestlcum hybrid ‘Elsie Hickman’



Any well-drained garden soil will do-the ideal is a sandy loam. Dig in compost or well-rotted manure before planting. Geraniums do best in full sun, but will tolerate light shade.


Little can go wrong at planting time. All you have to do is choose a day in late May or early June when the danger of frost is past. The soil should be moist and the pots containing the Geraniums should have been watered a few hours before planting is due to begin. Plant firmly-that’s all there is to it. Yet failures do occur and the plants seem to stand still instead of growing away. The usual cause is the lack of hardening-off-the plants should have been progressively acclimatised to the new environment and not moved from a warm greenhouse to the cold outdoors in a single day.


Geranium cuttings root very easily. Use the ends of green shoots, about 3-4 in. long, and insert in Seed and Cutting Compost. Do not use a rooting hormone and do not cover the cuttings-a small Rooting Bag is ideal for Geranium propagation. Take cuttings in July or August-they will root in 2-3 weeks after which they should be moved to 3 in. pots containing Potting Compost. During the winter months apply water sparingly and move to a cold frame in early April to harden off the plants for their late May move to the open garden. F, Hybrids can be raised from seed-sow under glass in January.


Pinch out the growing tips occasionally to increase thebushinessof the plants. Geraniums can withstand dry conditions better than most plants-constant watering is an easy way to kill them. Leave them alone, but if the dry weather is prolonged then a thorough soaking will be necessary. Feed occasionally with a liquid fertilizer which contains more potash than nitrogen. Remove the dead flowers to prolong the flowering season.


Before the first frosts arrive carefully dig up the plantsandshakeoffthesoil around the roots. Pot them up singly in Seed and Cutting Compost, using pots which are no largerthan necessary to house the roots. Reduce the height of the stems by about ahalfandcutoff all yellowing leavesand dead flower-heads. Put the pots in an unheated spare room or in a cold greenhouse. Do not feed them and water only when it is essential in order tostop the leaves from flagging. In spring move to a well-lit spot and increase the amount of water.


The two main pests of Geraniums attack the plants when they are growing under glass. Aphids and whitefly can seriously weaken growth-spray with Bio Flydown. Grey mould is another indoor nuisance-avoid stuffy condi-tions and spray with a systemic fungicide. Black root rot and foot rot are caused by using non-sterile compost, overwatering or damp air around the plants-there is no cure.

BEDDING GERANIUMS 1. Standard Varieties: Height 1-1.5 ft. Spacing 1 ft.

Propagate from cutlings taken in late summer.

P. ‘Paul Crampel’ Bright red, single

P. ‘King of Denmark’ Rose-pink, semi-double

P. Gustavo Emich’ Bright red, double

P. ‘Elaine’ Cerise-pink, single

P. ‘Jane Campbell’ Orange, single

P. ‘Queen of the Whites’ White, single

P. ‘Pandora’ Red, single

P. ‘Vera Dillon’ Purple, single

P. ‘Mrs Lawrence’ Pink, double

P. ‘Hermione’ White, double

P. ‘Festiva Maxima’ Purple, double

P. ‘Josephine’ Red, double 2. Irenes: Vigorous; free-flowering. Height 1-2 ft. Spacing T/i ft. Flowers semi-double; flower-heads larger than Standard Varieties.

P. ‘Springtime’ Salmon-pink


P. ‘Surprise’ Pink

P. ‘Electra’ Red with blue overtones

P.’Fire Brand’Red 3. Deacons: Compact. Flower-heads small but very numerous.

P. ‘Deacon Fireball Bright red, double P. ‘Mandarin’ Orange, double P. ‘Deacon Bonanza’ Bright pink, double P. “Deacon Coral Reef Pink, double 4. Rosebuds: Small flowers, centre petals remaining unopened like miniature rosebuds.

P.’Red Rambler’Red

P. ‘Appleblossom Rosebud’ Pink

P. ‘Rosebud Supreme’ Red 5. Cactus: Petals narrow and twisted.

P. ‘Fire Dragon’ Red


P. ‘Tangerine’ Vermilion 6. F, Hybrids raised from seed: Can be bought as seeds or bedding plants.

P. ‘Cherie Improved’ Salmon-pink

P. ‘Ringo’ Red

P. ‘Mustang’ Red

P. ‘Bright Eyes’ White-eyed red

P. ‘Sprinter’ Red

P. ‘Carefree Mixed’ Various colours 7. Miniatures & Dwarfs: Height 8 in. or less.

Spacing: 4-6 in.

P. ‘Red Black Vesuvius’ Red


P. ‘Pixie’ Salmon

P. ‘Caligula’ Red

P. ‘Grace Wells’ Lilac

FANCYLEAF GERANIUMS Height 1-1.25 ft. Spacing 9 in. Propagate from cuttings taken in late summer.


Height 1 -2 ft. Spacing 1 ft. Propagate from cuttings taken in late summer.

P. ‘Aztec’ White with pink blotches

P. ‘Lavender Grand Slam’ Lavender with purple blotches

P. ‘Grandma Fischer’ Orange with brown blotches

P. ‘South American Bronze’ White-edged maroon

P. ‘Geronimo’ Red, frilled

P. ‘Applause’ Pink, frilled

P. ‘Gay Nineties’ White with purple blotches

P. ‘Elsie Hickman’ Vermilion, pink and white

P. ‘Georgia Peach’ Peach, frilled

P. ‘Carisbrooke’ Rose-pink

P. ‘Sue Jarrett’ Salmon-pink with maroon blotches


Spread 3 ft. Propagate from cuttings taken in late summer.

P. ‘La France’ Mauve

P. ‘Ville de Paris’ Salmon-pink

P. ‘Abel Carriere’ Magenta

P. ‘Galilee’ Pink

P. ‘Mexicancrin’ Red-edged white

P. ‘Enchantress’ Pink

P. ‘Crocodile’ Foliage white-veined; flowers pale pink




ACID SOIL A soil which contains no free lime and has a pH of 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 apH of more than 7.3. Other terms are chalky and limy soil.

ALTERNATE Leaves or buds which arise first on one side of the stem and then on the other. Compare opposite.

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 the stem that carries it. An axillary bud arises in this angle.


BASAL SHOOT A shoot arising from the neck or crown of the plant.

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.

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 Undersurface 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.

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 sterilized soil (’loam compost’) plus other materials such as sand, chalk and fertilizers.

COMPOUND FLOWER A flower composed of florets.

COMPOUND LEAF A leaf composed of two or more leaflets.

CORDATE Heart-shaped.

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.


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 Rave been sown too thickly or grown in shady conditions.

DRILL A straight and shallow furrow in which seeds are sown.


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.


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 Frilly-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 is 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.


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.


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.


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.

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.

INTERNODE The part of the stem between one node and another.

INVOLUCRE A ring of bracts surrounding a flower or cluster of flowers.


JOINT See node.


KEEL Boat-shaped structure formed by the two lower petals of many members of the Leguminosae.


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.


MONOCARPIC A plant which dies after flowering and seeding.

MONOECIOUS A plant which bears both male and female flowers. Compare dioecious.

MUTATION A sudden change in the genetic make-up of a plant, leading to a new feature which can be inherited.


NECTAR Sweet substance secreted by some flowers to attract insects.

NEUTRAL SOIL A soil which is neither acid nor alkaline-pH 6.5 -7.3.

NODE The point on the stem at which a leaf or bud arises.

NODULE Swelling on the root of a member of the Leguminosae.


OBLONG Longer than broad, with parallel sides.

OBOVATE Egg-shaped, with broadest end at the top. Compare oval and ovate.

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. Compare alternate.

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. Compare obovate and oval.

OVULE The part of the female organ of the flower which turns into a seed after fertilization.

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. 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.

H A measure of acidity and alkalinity. Elow 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 seedling 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.


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.


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 Seepinching-out.

STRAIN A selection of a variety, cultivar or 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.


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.

TUNIC A dry and often papery covering of corms and some bulbs.


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.


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.


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.


WEED A plant growing in the wrong place.

WHORL Leaves, petals or branches arranged in a ring.

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