Rudbeckia

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Rudbeckia hirta ("Black-eyed Susan") flowerhead


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Asteraceae >

Rudbeckia >


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Rudbeckia (pronounced /rʌdˈbɛkiə/)[1] is one of at least four genera within the flowering plant family Asteraceae whose members are commonly known as coneflowers; the others are Echinacea, Dracopis and Ratibida.

They are herbaceous, mostly perennial plants (some annual or biennial) growing to 0.5-3 m tall, with simple or branched stems. The leaves are spirally arranged, entire to deeply lobed, 5-25 cm long. The flowers are produced in daisy-like inflorescences, with yellow or orange florets arranged in a prominent, cone-shaped head; "cone-shaped" because the ray florets tend to point out and down (are decumbent) as the flower head opens.

A large number of species have been proposed within Rudbeckia, but most are now regarded as synonyms of the limited list given below. Several of these currently accepted species have several accepted varieties. Some of them (for example the Black-eyed Susan, R. hirta), are popular garden flowers, distinguished for their long flowering times. There are many cultivars of these species.

Rudbeckia species are used as food plants by the larvae of some Lepidoptera species including Cabbage Moth and Dot Moth.

The name was given by Carolus Linneaus in honor of his teacher at Uppsala University, Professor Olof Rudbeck the Younger (1660-1740), and his father, Professor Olof Rudbeck the Elder (1630-1702), both of whom were botanists.


Read about Rudbeckia in the Standard Cyclopedia of Horticulture 

Rudbeckia (after the two Professors Rudbeck, father and son). Compositae. Cone-Flower. Very attractive summer-blooming perennials or biennials, usually with yellow flowers.

Leaves usually alternate, the blades undivided or in some species much cut, as in the common Golden Glow: fls. both tubular and ray-like, the former usually purplish, the latter always yellow; involucre hemispheric, its bracts imbricated in 2-4 series; receptacle conic or very rarely convex, with chaffy concave scales subtending the disk-fls.; disk-fls. perfect, fertile, their corollas 5-lobed: achenes 4-angled, obtuse or truncate at the apex; pappus none or of 2-4 short teeth.—There are about 31 species, not counting Echi- nacea, all of N. Amer. Of these scarcely a dozen are of horticultural importance. Under Rudbeckia are often included in nursery catalogues certain plants here referred to Echinacea and Lepachys. These three genera form an interesting floricultural group. Rudbeckia and Lepachys are typically yellow-fld. genera, while Echinacea is predominately rose-purple-fld. The chaff of the receptacle is usually persistent in Rudbeckia and deciduous in Lepachys. Among the hardy herbaceous species, there are several with striking habit and distinct foliage. There is a wide range of color in the rays of wild plants and many new races are yet to be perpetuated. Some of these with variations in the shape, color, length, color of disk-fls., and so on may serve as the basis of many fine forms. The season of bloom could doubtless be extended. The only full double form, apparently, is the Golden Glow, one of the best perennials of recent intro. Its origin is uncertain, but it appears to be a form of R. laciniata. About 1894 John Lewis Childs found it among some plants sent by correspondents. See Gng. 6:370. For structure of the Rudbeckia inflorescence or head, see Vol. III, Fig. 1535.

The cone-flowers are of easy cultivation in almost any soil and situation, from a semi-shady position to one in full sun. Most of the species are found inhabiting moist locations, but thrive well in the garden under the ordinary methods of cultivation, although R. laciniata and its double form, Golden Glow, do much better if abundantly supplied with moisture. R. hirta, the black-eyed Susan,—sometimes called by the children out West "nigger-heads,"—will thrive in the driest hottest situation, where many others would fail. The best known as a garden plant, and probably the showiest, is Golden Glow. If cut back severely when through blooming and well watered, it often produces a second crop of flowers. Autumn Glory will be well liked when better known. It is fine for massing and has a much longer blooming period than Golden Glow, commencing earlier and continuing until frost. It resembles R. nitida, an improved form of which, known as Autumn Sun, with bright primrose-yellow flowers, is a splendid acquisition. It grows 5 to 6 feet high, blooming from August to October. R. triloba is one of the very best, and, while a biennial, perpetuates itself through self-sown plants. It forms a dense twiggy bush somewhat over 3 feet high and nearly as broad if kept moderately well watered, and much smaller if in a dry situation. These plants may be used with effect as a border to a large bed of hybrid delphiniums, as the latter will tower above them and bloom in their young state. By the time the delphiniums are cut down for their second flowering, the rudbeckias hide their untidiness and are in their prime. The flowers are somewhat like those of the ordinary field black-eyed Susan, but smaller, and much more numerous. While doing best in full sun, they also do remarkably well in semi-shade, as under overhanging shrubs or in shady corners such as the north side of a house would afford. They like a good open soil. When grown in the open with one stake to the center or main stem, and a string run loosely around the whole plant—being,in fact, a string hoop—catching the larger outer branches to prevent breakage by the wind at the connection with the main stem, they make a very handsome compact plant. If well soaked at the roots, they may be taken up when in full bloom, and potted in a 10-inch pot, placed in a dark sheltered place over night, and then used for decorative purposes. They remain in good form for a month in a room or on the porch if not in a draft. They may also be taken up carefully and all the soil washed from the roots, and the roots placed in a large vase filled with water, where they present a bouquet arranged as Nature intended. An effective fall-flowering group may be formed by using the lighter-colored flower forms of Hibiscus syriacus—such as Totus albus, Lady Stanley, and elegantissima—for a center or background, and interspersing groups of the taller rudbeckias (except Golden Glow, which is too tall and spreading) and boltonias next to them. In front of these place R. speciosa and R. triloba, with the blue form of Aconitum Napellus, and for a border use R. bicolor var. superba, placed well to the front to be pulled up when its bloom is past. This group will give color from July until frost. The allied Echinacea purpurea and E. angustifolia are well adapted for grouping in open bays in shrubby borders, as their flowers are extremely durable and seem in harmony with such surroundings. Rudbeckias are easily increased by seeds, cuttings, or division. (W. C. Egan.)


Index

ampla, 10. fulgida, 6. speciosa, 7. amplexicaulis, 1. hirta, 5. subtomentosa,3. bicolor, 4. laciniata, 10. superba, 4. californica, 11. maxima, 9. triloba, 2. compacta, 6. Newmanii, 7. variabilis, 6. conspicua, 5. nitida, 8. vomerensis, 5.

R. angustifolia, Linn., ? Echinacea angustifolia.—R. Drummondii, Paxt. (Obeliscaria Drummondii, Maund.). Perennial, herbaceous: sts. slender: lvs. pinnate, the lobes linear-lanceolate, slightly jagged, acute: rays large, oblong, obtuse, reflexed, bright orange, deeply stained with dark brown at their base. N. Amer.(?). —Botanically unknown, probably some species of Lepachys. P.M. 6:51. B. 5:201.—R. pinnata, Vent., is Lepachys pinnata.—R. purpurea, Linn., is Echinacea purpurea.

Wilhelm Miller. N. Taylor.


The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


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References

  1. Sunset Western Garden Book, 1995:606–607

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