The History of Hibiscus
DEPARTMENT OF AGRICULTURE, CEYLON
BULLETIN No. 93
The Horticultural Hibiscus in Ceylon
Curator, Royal Botanic Gardens, Peradeniya
PRINTED AT THE CEYLON
GOVERNMENT PRESS, COLOMBO
Price 75 cents
DEPARTMENT OF AGRICULTURE, CEYLON
T. H. Parsons
Curator, Royal Botanic Gardens, Peradeniya.
The genus Hibiscus is a wide one, comprising some 150 to 160 species, of which many are known and grown in Ceylon. Chief among those of economic value is Rozelle (Hibiscus Sabdariffa L.) from the inner bark of the stems of which is produced a strong jute-like fibre. The succulent and fleshy sepals of the fruit capsules are also used by jam and jelly manufacturers for flavouring purposes and for pickles. The demand for these sepals, which are known commercially as " Karkade flowers ", is great and might warrant the planting of Rozelle on an extensive scale. Rozelle is grown commonly in Ceylon but always in small areas and in village gardens.
Other species of economic value include the Bandakka or Okra (Hibiscus esculentus L.), the young fruits of which are commonly used as a vegetable; Deccan or Bombay hemp (Hibiscus cannabinus L.) a shrub cultivated for the fibre obtained from the inner bark; Cuba bast (Hibiscus elatus Sw.), a West Indian bushy tree also producing fibre from the inner bark; and the local Bele patta (Hibiscus tiliaceus L.), a small tree of the low-country, the bark of which yields a strong fibre used for mats and cordage and as a substitute locally for grafting tape. The Tamil Perumaddi (Hibiscus micranthus L.), another local plant, is according to Trimen a valuable febrifuge.
It is, however, mostly in the horticultural and more ornamental types of Hibiscus that the owner of a garden in the tropics or sub-tropics is interested. There are several species of value in this respect but those in general cultivation are confined to three or four species with their many crosses and varieties.
In Europe and America the Hibiscus types in cultivation are many and include annual and perennial forms. Most common is the Swamp or Rose Mallow (Hibiscus Moscheutos L.), which in Ceylon would only be suited to up-country gardens.
The Hibiscus types used in horticulture in tropical and subtropical gardens embrace few species but many varieties. The outstanding species are considered below.
Hibiscus mutabilis L. is a Chinese plant of tree-like form producing large pink and white double flowers 4 to 5 inches across with dull, rough and hairy leaves. Outside Ceylon it is known also as the " Cotton Rose " or " Confederate Rose " of America and as the " Changeable Rose ", due to the fact that the colour of the flowers of the creamy white variety often changes to a deep reddish colour with age. The double pink and white varieties in cultivation in Ceylon, however, do not change their colours.
The East African species, Hibiscus schizopetalus Hk.f., is a handsome plant and grows well in Ceylon but it is not so well suited for hedges as some others owing to its slender and elongated habit of growth. The flowers are pendulous, usually red to orange-red in colour, with the flower petals deeply cut and recurved.
The " Rose of Sharon " (Hibiscus syriacus L.) is rivalled in popularity only by the shoeflower (Hibiscus rose-sinensis) and in mid and up-country gardens the violetblue form grows well, attaining a height of 4 to 5 feet in suitable soil and localities. This species has many forms with pendulous bell-shaped flowers varying in colour through the violet-blue, blue-purple, violet-red, rose and flesh-colour to white, and in both single and double forms. The varieties and forms, however, are more temperate to sub-tropical than the type and are very popular in America and the warmer parts of Europe.
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The Shoeflower (Hibiscus rose-sinensis L.) is common to most gardens in the tropics and is a serviceable hedge plant. Recently it has attained eminence in some countries owing to the marvellous variety of flower colour now available as a result of crossing of its varieties and of certain species but little has been written on the subject.
The common or garden shoeflower (Sapaththu Mal S.) probably originated in China but it is now in cultivation throughout the tropics. It is a large spreading shrub to a small tree with fairly large, thin, shiny green leaves and with rose-red flowers from 4 to 5 inches across. As an individual plant it is of average merit, but since it stands pruning admirably it is commonly used as a hedge plant.
The flowers form a red dye which is used locally for staining purposes and the flower petals are also used in jellies. It is stated that the flowers are used for dyeing hair and for blacking shoes, hence the local name of the " shoe-black " plant.
As a show plant, however, the type species is not often used since so many varieties and crosses have now become available which have large, single, and double flowers of many different shades.
HORTICULTURAL VARIETIES AND CROSSES OR HIBISCUS ROSA-SINENSIS.
The scope of hybridizing and crossing these fine flowers is immense, but little has so far been attempted locally. This is perhaps due to some extent to the paucity of indigenous species and to the limited range of colour among them.
There are twelve species indigenous to Ceylon, four of which are annuals, five are perennial herbs, one a scandent semi-shrub, and two are small trees. Of these species, eight have yellow flowers with purple centres, one white, one white to deep pink, one pink, and one pink to purple. Hibiscus collinus Roxb. (pale pink or purple), Hibiscus vitifolius L. (sulphur yellow with purple centre), and Hibiscus anqulosus Mast. with its variety (primrose yellow, and white to deep pink) are the only plants of any horticultural merit in themselves. They could however quite well be used as a basis of hybridization for multiplying the many varieties of Hibiscus now in cultivation, provided they are fertile in crossing, but generally speaking hybrids from Hibiscus schizopetalus and Hibiscus rosa-sinensis and crossings of the varieties of the latter among themselves would be the most probable source of further good forms.
The garden varieties of ornamenal Hibiscus in Ceylon do not by nature produce seed or do so very rarely, so that without artificial aid little seed is produced. The extent to which this occurs locally has yet to be exactly ascertained. If other local species of Hibiscus are used for crossing purposes satisfactory fertilization should be fairly well assured since these are self-fertile. When the operation of crossing is undertaken the stigmas and pollen must be dry. The flower normally opens in the morning and the best time to attempt artificial fertilization is during the morning hours.
PROPAGATION AND CULTIVATION
The ornamental species and certain of the varieties at present grown in Ceylon can be propagated without difficulty, usually by means of cuttings. Others, particularly the superior Hawaiian varieties, do not grow satisfactorily from cuttings but can be propagated by budding, using the patch or the T and inverted T methods.
The cuttings should be obtained from well matured and rounded shoots, ½ inch or a little more in diameter, and 8 to 10 inch sections should be used. A propagating bed with soil of a light sandy nature should be prepared and the cuttings inserted to a depth of 3 eyes or so-generally about 3 inches-in the soil. At Peradeniya the beds are made in the open and the cuttings shaded for the first week or so after insertion. After 4 to 5 weeks the cuttings will have formed sufficient roots to allow potting into bamboo pots for the convenience of later transport, if necessary. The cutting will have formed sufficient root system for planting out at about 2 months from insertion of cuttings. Since the propagating bed is of very sandy soil, water should be regularly given and the bed not stinted of water in any way throughout the period of rooting.
Cuttings for later budding should be of Hibiscus rosa-sinensis or of those varieties which are of vigorous growth and suited to local conditions, and the same procedure in rooting is followed to the potting up stage.
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The potting mixture should consist of one-third each of well decayed cattle manure, leaf mould and sand, and good drainage assured. Buddings are best made on the T or inverted T method. Though grafting is also very successful, the quantity of material required is greater and budding is therefore more economical.
As has been stated above, our present ornamental varieties do not naturally produce seed but if seed is desired, it can sometimes be obtained by artificial pollination. In this case the seed capsule should be picked when ripe, which occurs a month or less after pollination in the crossings but later in the hybrids, and according to whether the plant is in an open or sheltered position. The capsules should be dried and the seed carefully shaken out and sown in pots or pans in a light friable soil to which a layer of clean river sand has been added, the seed being planted about a quarter of an inch deep. To prevent wash by water during the germinating period the pot or pan should be placed in a saucer of water and a glass cover placed over top of the pot or pan.
Experiments recently undertaken in crossing the better varieties of shoeflowers at Peradeniya have been very successful. Of the species, Hibiscus Abelmoschus L. and Hibiscus collinus Roxb. have been utilized and of the varieties, Nos. 15, 20, 21, 26, 47, 51, and 52. These seven varieties have proved fertile in every case, the seed having germinated well in 10 to 12 days. The hybrids, though taking much longer than crossings among varieties to set seed, germinated equally freely and as quickly.
Growth is fairly rapid and seedlings should be transplanted to earthenware or small bamboo pots on reaching a height of 2 to 2½ inches, being subsequently grown on till large enough to plant in a permanent site.
If the size of flower is to be maintained periodical attention to the cultural requirements is most necessary and well decayed cattle manure should be forked into the bed at frequent intervals.
Since the varieties vary widely in habit of growth, no hard and fast planting distances can be given. All Hibiscus plants show to best advantage when spaced widely enough to allow of ample development. Individual plants at Peradeniya are planted 12 to 15 feet apart.
The majority of the local varieties stand pruning back fairly frequently. Some object to this treatment and the descriptions of varieties given below will denote these.
Few plants are less troubled by insect and fungus attacks than these horticultural forms of Hibiscus.
The common leaf-eating pests are the cotton leaf-caterpillar (Anomis indica) and a small flea beetle (Podagrica ceylonensis) which spot the leaves. These can he controlled by spraying the plants periodically with lead arsenate at the rate of 1 oz. of the powder in 2 gallons of water. The only plant-sucking bug of any importance is the black scale (Saissetia nigra) for which kerosene emulsion, 1 in 8, or fish oil soap, 1 lb to 4 gallons of water are useful remedies. Branches attacked by the stem-borer caterpillar or red borer (Zeuzera coffeae) should be pruned off below the injury and burnt.
Fungus attacks are limited mostly to root diseases caused by Poria hypobrunnea Petch. and Rosellinia bunodes (B. & Br.) Sacc. The complete eradication of diseased plants, especially the removal of all roots, is all that is required to arrest the progress of the disease. Pink disease caused by Corticium aalmonicolor B. & Br. is of rare occurrence. The cutting out of the affected branches, together with a few inches of the healthy portion, should prevent the disease from spreading. All diseased material should be burnt.
Until relatively recently, a limited selection of good horticultural varieties of Hibiscus was cultivated and distributed from the Royal Botanic Gardens, Peradeniya. The origin of these is somewhat obscure, though they are believed to have been obtained from a local planter whose hobby it was to hybridize local and imported varieties. His original plantation has long since been abandoned and the plants, where still alive, have apparently reverted to type, although plants cultivated at Peradeniya have been maintained.
Through the courtesy of the Director of the Experiment Station of the Hawaiian Sugar Planters' Association, Honolulu, we received about 3 years ago 15 new and beautiful hybrids and crosses, grafted on to the hardy type plant, Hibiscus
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rosa-sinensis. These have been carefully tended and, with some of the better of our older varieties and forms, a selection of the best has been assembled and planted in one representative section along the Lake Drive in the Royal Botanic Gardens, Peradeniya. Those varieties and forms which are of outstanding merit are described below, and have been consecutively numbered and, where possible, named. Since so little literature containing the description of these fine flowers is available locally, the particulars attached should be helpful and of some permanent value. Colour description in its exact shade or tint is, at best, to the ordinary gardener a very contraversial subject and to clarify this as well as possible, the colour description given below is firstly that of the draughtsman, based on the colour or combination of colours used in the paintings, followed by the colour as given in " Ridgway's Colour Standards and Nomenclature" indicating the number of the plate, the hue, the tone, and the name.
Further descriptions as to freedom or otherwise of growth and flower and method of propagation are based on our experience of plants grown at Peradeniya.
No. 1. Brilliantissima - Peradeniya origin, double, carmine. (Ridgway I. 1. i; carmine.) Flowers in fine full heads, of rapid growth and easily propagated from cuttings. Becomes a large bush. Flowers 5 inches in diameter.
No. 2. Hiawatha - Peradeniya origin, double, amaranth red to deep rose. (Ridgway XII. 71. b; rose colour.) A normally strong grower and well-shaped bush. In flower most of the year. Propagated by cuttings. Flowers 6 inches in diameter.
No. 3. Albus - Peradeniya origin, single, ivory white to pale yellow. (Ridgway V. 25. f; sulphur yellow, with carmine centre.) A rather delicate shrub of somewhat slower growth than most others, slender habit, flowering very freely. A very delicate shade of colour. Propagated by cuttings. Flowers 5 inches in diameter.
No. 4. Variegata - Peradeniya origin, double, scarlet with white stripes. (Ridgway I. 1. -; spectrum red, petals edged with white.) A large-sized shrub or small tree if allowed to grow. Very fine heads of scarlet and white flowers produced freely. The amount of variegation varies in individual flowers. Propagated by cuttings and by budding. Flowers 4½ to 5 inches in diameter.
No. 7. Mrs. Walker - Hawaiian, single, pale salmon pink, white centre. (Ridgway XXVII. 5. d; and XXVII. 1. f; pinkish vinacious to pale vinaceous.) A very delicate shade of pink and most attractive. Rather shy flowering to date, growth fairly free. Propagation by budding. Flowers 7 inches in diameter.
No. 8. Red Rover - Peradeniya origin, single, large, deep rose. (Ridgway XXVI. 7., -; spinet red, carmine centre.) A very strong and rapid grower, leaves in clusters along stem, habit not unlike Hibiscus schizopetalus, very large and fine flowers, free flowering. Propagated by cuttings. Flowers 7 to 8 inches across.
No. 9. Salmo - Peradeniya origin, double, deep coral red to ornage. (Ridgway XIII. 3. -, XIII. 5. -; jasper red and coral red.) A very choice colour and free flowering. Flowers apt to fall early on own rooted cuttings but when grafted are retained on plant for a longer period. Shy growth in early stages. Propagated by cuttings and by budding. Flowers 5 inches in diameter.
No. 11. Superb - Hawaiian, single, scarlet red to pale crimson. (Ridgway XII. 69. -; and XII. 71. b; Tyrian rose and rose colour.) A rich and striking colour but not so free flowering as most others. Most attractive and growth fairly rapid. Propagated by budding. Flowers 6 inches in diameter.
No. 14. Gloria - Hawaiian, single, deep orange, dark crimson centre. (Ridgway II. 9. b; and II. 11. b; bittersweet orange and salmon orange.) Free flowering and nearly always in flower, the largest in size of the collection. Free growing and of erect habit. Propagated by budding. Flowers 8½ inches in diameter.
No. 15. Gold Mine - Hawaiian, single, deep gamboge yellow with white and crimson centre. (Ridgway IV. 19. b; apricot yellow.) A fairly free grower but rather shy flowering. A rich shade of yellow with crimson centre. One of the most striking of the collection. Propagated by budding. Flowers 6½ to 7 inches in diameter.
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No. 16. Evergreen - Introduced, single, flame colour petals fading at tips, maroon centre. (Ridgway II. 7. b; and II. 7. d; grenadine to grenadine pink.) Free growing and ornamental shrub, flowers normally smaller than most but improved with good cultivation. A very rich colour, propagated by budding. Flowers 5 inches and over in diameter.
No. 18. Wilhelmina Tenney - Hawaiian, single, scarlet and salmon. (Ridgway I. 3. -; to II. 11, d; scarlet red to light salmon orange.) Free grower, leaves narrow and crenate, and a handsome foliage bush. Flowers very freely and a fine combination of colour. Propagated by budding. Flowers 6½ inches in diameter.
No. 19. Mrs. Wise - Hawaiian, single, orange to buff petals, pinkish red centre. (Ridgway III. 17/ f; and XXVI. 71. b; pale orange yellow to spinet red.) A quick grower suited to almost any position. Flowers of an attractive colour, petals narrow and less flaccid than other varieties. Propagated by budding. Flowers 6½ to 7 inches in diameter.
No. 20. Daffodil -- Hawaiian, semi-double, chrome yellow with tinted red centre. (Ridgway IV. 21. b; and I. 5. i; Empire yellow and Brazil red.) Of rather slow and scanty growth but fairly free in flowering and attractive in its colours and semi-double flowers. Propagated by budding. Flowers 5 inches in diameter.
No. 21. Prince of Japan - Hawaiian, single, deep scarlet to pale scarlet. (Ridgway I. 1. -; and I. 3. -; spectrum red and scarlet red.) A very striking colour, free flowering, growth somewhat slow and habit more dwarf than most others. Propagated by budding. Flowers 8 inches in diameter.
No. 25. Aurora Sport - Peradeniya origin, double, amaranth red. (Ridgway XII. 69. i; and XII. 71. i; amaranth purple and pomegranate purple.) A sport from No. 29, of rapid growth, striking freely from cuttings. Frequently in flower and requires periodical pruning back. Flowers 5½ inches in diameter.
No. 26. Kruss - Hawaiian, single, pale crimson with deep carmine centre. (Ridgway I. 1. d; cosine pink.) A still deeper shade of Nos. 7 and 52 and of free flowering habit and rapid growth. A most attractive plant, propagated by budding. Flowers 8 inches in diameter.
No. 29. Aurora - Peradeniya origin, double, vermilion red, with white centre. (Ridgway I. 1. b; and I. 3. d; begonia rose and geranium pink.) A very free flowering plant, apt to reach large dimensions and needing periodical pruning back. In flower all the year round, propagated by cuttings. Flowers 6 inches in diameter.
No. 31. Venus - Peradeniya origin, single, deep scarlet. (Ridgway I. 1. - ; spectrum red.) A strong, rapid and clean grower, specially suitable for hedge purposes. Flowers very freely, flowers lasting longer than most. Propagated easily by cuttings. Flowers 6 inches in diameter.
No. 35. Safrano - Peradeniya origin, single, deep orange changing to lemon or cream at tips of petals. (Ridgway XIII. 3. -; and XVI. 19. f; Jasper red and cream colour.) Shy in growth but a free flowering plant and very attractive in its combination of colours. Propagated by cuttings and by budding. Flowers 5 inches in diameter.
No. 38. May Walker - Hawaiian, semi-double to double, deep vermilion red. (Ridgway I. 3. b; and I. 3. d; rose doree and geranium pink.) One of the most free flowering of the Hawaiian crosses. Growth very rapid, attaining the height of a small tree if left unpruned. Always in flower and a very handsome plant at all times. Propagated by budding. Flowers 6½ inches in diameter.
No. 40. Anna Shaw - Hawaiian, single, pale yellow with white centre. (Ridgway IV. 23. b; pale lemon yellow.) A very shy and slow grower, wide and crenate leaves, shy flowering and of great delicacy. Propagated by budding. Flowers 6 inches and more in diameter.
No. 47. Luna (Shaw type). Hawaiian, single, pale chrome yellow. (Ridgway IV. 21. - ; lemon chrome.) A very fine delicate shade and perpetually in flower, clean and very attractive. Growth slow somewhat stunted, leaves particularly broad and almost without petiole. Propagated by budding. Flowers 6 to 7 inches across.
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No. 48. Kissed - Hawaiian, single, deep carmine to pale carmine. (Ridgway I. 1. i; and I. 3. i; carmine and nopal red.) Very attractive, fairly free growing, growth normal in habit, propagated by budding. Flowers 7½ inches in diameter.
No. 52. Agnes - Hawaiian, single, very pale crimson. (Ridgway XXVII. 1. d; and XXVII. 3. d; vinaceous to corinthian pink.) Similar to No. 7 but deeper in colour and much more free flowering. Of moderate growth and from the early stages rarely without flowers which are of immense size. Propagated by budding. Flowers 8 inches in diameter.
No. 53. John Walker - Hawaiian, double, pale lemon to white yellow. (Ridgway V. 25. f; sulphur yellow.) A remarkably fine double. Fairly shy in flowering but of an exquisite shade, varying in its stages from pale yellow to ivory white with petals partially transparent. Of normal growth, propagated by budding. Flowers 4 inches in diameter.