All require a very well-drained planting medium such as a gravely, gritty, sandy mixture. A full day of bright light or sunshine is essential to maintain normal characteristics. Those plants grown in low light and watered year-round will lose their stre ntgh and become large leaved and floppy. They generally are short lived if overwatered and not given full sunlight. This group is easly propagated from seed or cuttings.
Pelargonium alternans in cultivation is usually so overwatered and overfertilized that it is hardly recognizable as the species that it is. This native of the dry western and southern parts of the South Western Cape has very small finely divided leaves at the ends of very compact woody stems. Flowers are white or pink and usually produced in clusters of up to four on an unbranched flowering branch that is nonpesistent. Correctly grown this is a beautiful, compact and dense plant.
Pelargonium carnosum is a very succulent plant that has a large underground stem. This plant has a large distribution in semidesert areas of South Africa. As is normal with plants that have a large distribution area, there is a lot of diversity in this species. Plants should be grown hard to maintain their characteristics such as knobby branches and a dense compact main stem. Plants in cultivation have a longer flowering period in winter and spring. Flowers are small and white to pinkish with red streaks on the upper petals. Probably the most frequent succulent Pelargonium species in cultivation, although many plants in cultivation with this name are not this species. Easy to grow.
Pelargonium cortusifolium is one of the most beautiful of succulent plants. Native to coastal Southwest Africa, it has leaves that are densely covered with silvery hairs that absorb the night time fog. The succulent stems are irregularly branched and grow to about 35 cm (1 foot). The flowering period is very long, often blooming before the plant comes out of dorinancy. Flowers vary from white to pink to purple- pink. The upper petals are usually the darker color, and most of the upper petals have purple-pink spots or streaks. The flowers are delightfully fragrant, sweet and fruity to some. It requires a very well drained planting medium and careful watering. If overwatered, especially when dormant, it is easily killed.
Pelargonium echinatum, the 'sweetheart geranium,' is native to Namaqualand, South Africa. The leaves are deep green and lightly covered with white hairs, while the underside of the leaf is more hairy and gray-green. The stems are more woody than succulent, and are covered with dried stipules (the little projection at the base where the leaf stemjoins the main stem). Flower color varies from white through shades of pink and purple. Most forms have dark red blotches on the upper petals, and somc forms have blotches on all petals. The large showy flower clusters are produced midwinter to spring and large old plants are a mass of flowers. This plant will stay quite compact if grown in full sun in a well-drained planting mixture and watered deeply when the planting mixture is quite dry on the surface. Grown in the ground where the climate is mild, in a few years it will become a plant that is more than I meter (3 feet) across, and will have up to a thousand flowers open at a time during late winter and spring. The most frequent form in cultivation is white with blotches on the upper two petals and all petals fade to pale pink as the flower ages. Easily propagated from seed, cuttings and tuber cuttings. When the days start getting very warm this plant will turn yellow and drop its leaves. When this happens, stop watering until new growth begins in the fall.
Pelargonium fulgidum is one of the few species with bright red flowers. Often used in the past to hybridize with other species, the red color of many old hybrids is from this plant. Native to the western coastal districts of South Africa, this plant lives on winter rains and is dormant during summer. A very pretty plant when in growth, the green leaves are covered with silvery hairs, and the plant is covered with clusters of bright red flowers. Bright light is essential for compact growth. This species will grow year-round if it never gets dry. If allowed to dry out in the spring it will go dormant and cannot be stopped. This plant has great potential for future hypridizing.
Pelargonium gibbosum is called the "gouty pelargonium" because of its swollen joints. The flowers are among the most yellow in the genus Pelargonium, and are produced in large clusters at the ends of fairly long branches. The blue-green leaves are semi-succulent and are usually three part and deeply notched or toothed. The flowers are sweetly scented at night, most likely to attract night flying pollinators. This is another plant that will grow year round if watering is maintained. Plants are usually much more compact and dense if plants are allowed their normal dormancy. Easily propagated form stem cuttings, root cuttings and seed. Native to sandy and rocky places along the western coast of South Africa.
Pelargonium hirtum does not look like it could possibly live through a summer dormancy. The short stems, up to about 20cm, (8 inches) are not particularly succulent, but rather, slightly succulent and woody. It is a very low bushy plant that is c overed with very finely divided leaves that are very soft to the touch. It looks very much like a fern when in growth. Specialized flowering branches are produced that are thinner than the normal branches. The small lavender-pink flowers are produced in clusters of three to five flowers. This species is fairly common in the Cape Peninsula, growing in sand and rocky areas. It goes completely dormant in late spring and begins to grow again in the fall. W hen grown in a small pot it should have a little water occasionally during the summer or it will dry out (it develops a much smaller root system in a pot than in habitat). If watered too much during dormancy it will quickly rot. Easily grown from seed which is produced in quantity.
Pelargonium klinghardtense is one of the most succulent of all
Pelargonium species. The short compact stems produce branches mostly from the base that are rather knobby. Plants in cultivation are rarely over 30 cm (1 foot) tall. Leaves are usually very ruffled at the edges, The flowers are borne on a multi-branched stem that is often larger than the plant. The flowers are white with no markings, the petals being smaller than the green sepals behind them. This extremely succulent Pelargonium specics is native to southern coastal areas of South West Africa and the extreme northwest corner of South Africa. The part of Africa has summer temperatures that are usually very hot, and rain is little to none at all in some years. Early morning mists and fog from the nearby ocean give some moisture. In cultivation this plant will grow year-round if watered continuously, but the plant will be more compact and the leaves smaller and more succulent if allowed a dormancy. Grown in less than full sun and watered year-round it is hardly recognizable as the plant it should be. Best raised from seed as cuttings really mark up a specimen plant and are also difficult to root.
Pelargonium praemorsum is a small shrubby plant, multibranched form the base, and up to 1 meter (3 feet) tall in habitat, but usually less than half that in cultivation. This speeis is native to Namaqualand, South Africa. The leaves are small and are usually divided into five palmate segments. The bark on the branches of oldcr specimens is a shiny brown color. The flowers are very large and are usually off-white to cream and ivory, usually having reddish-purple streaks in the upper two petals. An unusual color form that was discovered is being grown at the fantastic Kirstenbosch Botanical Gardens in Cape Town. Flowers are produced winter to spring. The flowers are produced at the tips of the stems and are very showy. When grown in a small pot, this plant always looks like a few sticks with small green leaves. When grown in a large container with very good drainage the plant will fill in at the base and make a very full specimen.
Pelargonium spinosum is one of the most unusual Pelargo- nium species. It is native to the extremely dry Richtersveld area of northwestern Cape Province, and in southwest South West Africa. The soils in these area are very sandy and rocky and drain very rapidly. Winter rainfall is normal but slight. Early morning fog and mist may give this species some of its moisture. In cultivation the subsucculent stems grow to about 65 cm (2 feet) and have a peeling paper-like bark on the older stems. The glossy deep green leaves are formed at the end of long leaf stems (petioles). It is the petioles that make this plant unique, being up to 11 cm. long (4 inches). when the leaves die, they gradually decompose as does the tip of the petiole, yielding a sharp point. The petioles are more formidable than dangerous as they are not really a hard spine. Flowers are large and very showy, but are not readily produced in cultivation. Flowers are nominally produced in habitat in spring, but this is greatly influenced by when the rains occur. This plant requires long days of bright light, careful watering, and a very well drained planting mixture low in organic matter. Propagation is easy from seed when it can be obtained. Cuttings are difficult to root but seem to root best just before the plant goes dormant as the weather is getting warm.
Pelargonium alchemilloides is a very widespread species in South Africa. As usually happens with a very widespread species, it is quite variable from location to location. It is a low, spreading plant, growing from a central rosette of leaves, and forming flowering branches that spread out and continually produce flowers from the tip of the branch. Leaves vary from complete to deeply lobed, smooth or densely covered with silvery hairs, some with a dark zone in the leaf and others without. Flower color varies from white, cream, pale yellow, to shades of pink. Flower size is quite variable also. The showiest forms have quite large white or deep pink flowers and often have nice silvery leaves. This is one species that will grow all year if given water continuously. Although it is tuberous it does not seem to have a definite dormant period (at least in the forms that I have grown, but I have not grown any of the forms from northeastern South Africa). It tends to die out after a few years but is very easy to reestablish as it is a prolific seed producer. Propagation by tuber cuttings is also easy.
Pelargonium barklyi is a native of western coastal areas of South Africa. The tubers are fairly large and round. A stemless rosette of leaves is formed at the soil surface. Leaves are very distinct, being round, and having depressed veins radiating out from the base. The depressed areas are a darker color than the rest of the leaf. Flower stems are very long, up to 65 cm. (2 feet), and are topped vath five to seven, or more, flowers that are pure white or white with slight pink veins at the base. This is one species that does best in a large container. It just cannot produce a largd enough tuber in a small pot to survive the summer dormancy in really warm climates. If grown in a small container, it will survive dormancy better if stored away from really warm areas. This beautiful plant is easily grown from seed.
Pelargonium caffrum is one of the fringed petaled species. It is native along the southeastern coast and inland of Cape Province, where it usually grows in grasslands that receive some rainfall throughout the year. The tubers are large, and produce a very short above ground stem with a rosette of leaves that are variable. As the plant begins to grow, the leaves are usually entire, with each subsequent leaf being divided until at maturity the leaves are deeply divided. Flowers occur in the spring and summer seasons and are burgundy-purple and yellowish- green with the petals deeply fringed or divided for more than half of their length. An easily grown species, it should be kept moist when in growth, and will grow all year if not allowed to dry out in summer. Propagation is easy from tuber divisions or tuber cuttings.
Pelargonium incrassatum is one of the most spectacular of the tuberous species when in bloom. This native of Namaqualand is a winter grower, and in habitat it grows in very well drained stony and gravely soil derived from old decomposed granite. It grows as a low rosette of leaves that are pinnately incised and are densely covered with silvery-white hairs. Many individual unbranched flowering stems are produced. Up to forty flowers are produced in each scape, the flowers being a brilliant purplish-pink. The upper two petals are much larger than the three smaller lower petals. Flowers are produced in spring and early summer, then the plant goes dormant until the following fall. This species should be grown in a large container as it produces much larger tuber in a large container, and the large tuber will enable it to survive summer dormancy. Plants grown in small containers do not easily survive dormancy. Easily grown from seed, which is readily produced from mature plants. This beautiful plant has been in cultivation since about 1794.
Pelargonium lobatum has the largest leaves of any Pelargonium. This species has very large tubers and leaves that can be over 30 cm. (1 foot) across. Native to the South Western and Southem Cape, this species grows mainly on sandy flats in a winter rainfall area. Tubers can be very large, indicating that a large container is necessary for the plant to grow normally. Flowers are variable from almost black, with a yel- lowish edge, to almost yellow with a small purple-black streak in the center of the petals. Flowers are held on branched stems well above the plant, and the flowers are very fragrant at night. This very bold looking plant is easily propagated by tuber division, cuttings or seed. An easy plant to grow if given a large container and a summer dormancy.
Pelargonium lridum is other species that is easy to grow. It is quite variable plant, and is native to a large area of the eastern portions of South Africa and countries north of there. These areas are summer rainfall areas, and Pelargonium lutidum is nor-ally found in grassland areas that are constantly moist during the Summer months. In cultivation it will grow constantly if watered all year, but will flower only during the summer months. This species has a large tuberous root system. Leaves are very variable from area to area, but usually begin form dormancy as a complete individual leaf and as the plant grows each successive leaf is more deeply divided until, at maturity, most forms have deeply divided leaves. Flowers are in large heads on tall stems. Flower color varies from white, shades of pink, yellowish-green, and red forms are recorded from countries north of South Africa. This is an easily grown species, and if grown in a large container, will produce many flowers and tubers. It will grow all year if watered constantly, but should never be kept wet. Easily propagated from the many tubers produced.
Pelargonium oblongatum has a long vertical tuber, the upper part appearing above ground. This native of the hot and arid areas of northern Namaqualand grow from winter to spring and receives very little natural rainfall in habitat. Leaves are fairly large, up to 10 cm. (4 inches) long, and 8 cm. wide (3 inches), entire and covered with course hairs. The flo ers on large old plants are truly spectacular. @lfwers are large, pale yellow with purple-red streaks and veining in the upper petals. The flowering stems branch and produce clusters of flowers over many weeks of time. Large older plants will produce many flower stems and the plant is entirely covered with flowers. This is another species that requires a very well drained planting medium, regular watering while in growth, but should never be kept wet. A dry dormancy is required. To produce a plant with large tubers and the most flowers, a large container is necessary, as a small pot limits the size the tuber can attain. This spectacular and rare plant can be propagated from seeds and tuber cuttings when they can be obtained.
Pelargonium pinnatum is one of the more dependable tuberous species to grow. It is native to areas of the southwestem part of Cape Province, South Africa. A stemless rosette of leaves is produced at the beginning of the growing season in late fall or early winter. The leaves are pinnately divided and up to 25 cm. long (10 inches) but are usually shorter in cultivation. The leaves are usually quite hairy and are very variable as to the size and numbcr of leaflets on each leaf stem. The flowering stems (pedunclds) are usually branched to form many flower heads. A large old plant will be completely covered with flowers. Flowers are variable in size and shape, and in shades of white, pale yellow, and shades of pink and may have dark pink or red streaks or blotches in the upper petals. This species can be grown successfully in small pots, but will produce quite large tubers and more flowers if grown in larger containers. It must be kept dry during the dormant period, and if grown in small containers they should be protected from the hot sun during the summer dormancy or the tubers can completely dehydrate and die. Easily propagated from tuber divisions and cuttings and seed.
Pelargonnium pulveruientum is an unusual large and bold plant. It has a very large tuber that is brown and covered with splitting cracked bark. It produces annual stems above ground that die back during dormancy. It is native to the Eastern Cape, Transkei and Natal, where it grows in sandy soils in grassland areas. The leaves are blue-green and fairly large and semisucculent. Leaves are usually covered with coarse hairs and the leaf edges are lined with long soft hairs. The branched flowering stems are held above the plant and can be up to 50 cm (18 inches) although they are usually less. The flowers are pale yellow and are usually blotched brownish or dark purple in the center of the petals. There are forms with almost no blotching, and forms with only the three lower petals that have blotches. In habitat it grows and flowers early spring through summer, but in cultivation it will adapt to winter growing/summer dormant conditions, or it can be grown all year if water is provided all year. Plants in small containces do not develop well as the tuberous root system is quite large. Easily propagated from seed and division of the tuber.
Pelargonium rapaceum has unique pea-shaped flowers. It is easily identified when in flower. A rosette of leaves is produced from the tuber in late fall. Leaves are long and narrow and deeply dissected into leaflets that are soft and hairy. The flowering stems can be single or multibranched. Flower heads usually have many flowers and flower color can vary from creamy-yellow, through shades of yellow and shades of pink, most having red stripes on the lower part of the upper petals. The tuber can reach 10 cm. (4 inches) in diameter and usually produces a series of small tubers off, or around the base of the tuber. This species can be grown in small containers but for large really showy plants, a larger container is essential. Easily propagated from seed which is readily produced, and from tuber divisions and cuttings. Pelargonium rapaceum is native to Namaqualand, the Karoo, and the Eastem Cape, and is most abundant in the South Western Cape, growing in sandy soil and on dry, stony mountain slopes.
Pelargonium rodneyanum is a tuberous native of Western Australia, New South Wales and Victoria, Australia. Little information is available on this species in this country. This species is winter and spring growing and goes dormant in the heat of the summer. Masses of small, long, narrow tubers are produced, which are easily divided to produce more plants. Very compact rosettes of leaves are produced, up to 10 cm (4 inches) long, and 2.5 cm. wide (1 inch). The branched flower stems are up to 25 cm (10 inches) tall. Flowers on the form in cultivation in this country are a bright purple-pink, 2.5 cm (1 inch) across, and are produced in heads of up to twenty-five flowers. Seed is readily produced if flowers are selfpollinated.
Pelargonium triste was the first Pelargonium species introduced into cultivation. It has a very large branched tuber from which the annual flowering branches and leaves are produced. It is native to the Western Cape and Southern Cape areas of South Africa, growing in sandy soils. It is a very variable species. A full grown plant is large, up to 1 meter 3 feet) across.
Leaves are carrot like, being quite finely divided, and very hairy. Flowers are produced on branched stems, and are variable from almost all yellow through yellow with slight brownish patches on the lower petals. Easily propagated from seed, but even easier by tuber divisions. This species should be grown in a large container, as the tuberous root system is very large, and a plant will never reach the beauty of a mature plant in a small container. Plants that are watered all year tend to struggle and make very weak growth. They should be allowed dormancy during summer.
Most Pelargonium seeds have a very hard, water resistant seed coat. Many also have chemical inhibitors in the seed or in the seed coat, which prevent all the seeds from germinating at the same time in nature. Germination can be very cffatic and can take place over a long period of time. There is a way of overcoming the long time periods and the inhibitors; that is by scarifying the seeds.
Scarifying is easily accomplished by gently rubbing the seeds between sheets of sandpaper, or preferable by gently scraping a small hole in the side of each seed. Ainother method is to simply cut off a very tiny portion of the end of the seed with a very sharp, clean blade. This allows water to enter the seed and begin the process.of germination in a reasonable short-time. Most scarified seeds will germinate in between two and twentyd ays. NOTE: Before scarifying the seeds, you must remove the seed from the seed husk (mericarp).
Seeds of winter growing species should be planted in late summer so there is still enough warmth to get good germination and established seedlings before colder weather. Those species that arc not winter growers can be growne from seed any time of the year, but a spring sowing of seeds is usually most successful.
Plant the scarified seeds in pots or trays in a loose, well drained sandy medium. They should be covered with about 6 mm (1/4 inch) of the planting mixture. A temperature of 16 degrees Celsius ( 60 degrces F.) or higher is adequate. Good air circulation is essential or fungus prohlem may occur. Bright light is essential, but full sun might burn the seedlings until they have begun to establish and mature. If the seeds are planted in community pots or trays, the seedlings should be transplanted when they have two to three leaves.
Propagation by root or tuber cuttings is also quite easy. Many species produce clumps or clusters of tubers, or even strings of tubers. These can simply be divided and planted up. Succulent roots can be cut into 5-8 cm. (2-3 inch) sections and planted. A most important thing to remember is the cutting or tuber division must be planted with the end upright that was attached to the plant. Otherwise it will usually not grow, or if it does it will take a very long time as the new growth will be from the bottom of the cutting. I find that if the cuttings or tubers are planted with the tops just at or above the surface of the planting medium so that they receive light, they will form growth buds quicker.
Research in propagation by leaf cuttings is being done by Mr. Ernest de Marie at Comrnll University, and when results are known, the information will be made available.
Aphids can become a problem on plants grown out of doors but are easily removed by washing with a strong stream of water. The new insecticide soaps are also effective and are relatively harmless to people.
The caterpillar larvae of some butterflies and moths do damage pelargoniums, but are easily controlled with any of the biological sprays or dusts that contain the bacteria Bacillus thuringenesis, such as Dipel.