|Hypericum subsp. var.||St. John's Wort, Rose of Sharon, Aaron's Beard|
The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. All members of the genus may be referred to as St. John's-wort, though they are also commonly just called hypericum, and some are known as tutsan. The marsh St. John's-worts are nowadays separated in Triadenum.
St. John's-worts vary from annual or perennial herbaceous herbs 5–10 cm tall to shrubs and small trees up to 12 m tall. The leaves are opposite, simple oval, 1–8 cm long, either deciduous or evergreen. The flowers vary from pale to dark yellow, and from 0.5–6 cm in diameter, with five (rarely four) petals. The fruit is usually a dry capsule which splits to release the numerous small seeds; in some species it is fleshy and berry-like.
|Standard Cyclopedia of Horticulture|
Deciduous, or sometimes evergreen, usually low shrubs, or herbaceous perennials, rarely annual: lvs. opposite, short-petioled or sessile, entire, dotted with pellucid or opaque glands, without stipules: fls. usually in terminal cymes, less often solitary, sometimes axillary, yellow, rarely pink or purplish; sepals 5, imbricate or valvate, often unequal; petals 5, oblique, convolute in bud; stamens usually numerous, free, or connate at the base into 5 or 3 bundles, rarely as few as 3; ovary superior, with 3-5 parietal placenta;, 1-5-celled; styles 3-5, distinct or united: fr. a septicidal caps., rarely a berry; seeds usually cylindric, many, rarely few.—About 200 species in the temperate and subtropical regions of the northern hemisphere, few in the southern hemisphere.
The St. John's worts are exceedingly variable in habit: most species in cultivation are low shrubs, either upright with ascending or spreading branches, or tufted or procumbent; the herbaceous species have often stiff upright wand-like stems or are diffuse or procumbent: the leaves are usually narrow and rather small; the yellow, rarely pink or purplish flowers appear usually in profusion during the summer in terminal clusters, less often solitary, sometimes axillary and forming leafy racemes or panicles; they vary from 1/5 inch to 3 inches in diameter; the capsular fruits are inconspicuous or even unsightly when ripe, only the fruits of the one berry-bearing species are ornamental. Most of the species are tender in the North. H. aureum, H. prolificum, H. lobocarpum, and other American species, also H. calycinum and H. patulum Var. henryi, with some protection, have proved hardy as far north as Massachusetts, and H. kalmianum and H. ascyron are still hardy in Canada. Others like H. patulum, H. hookerianum, H. moserianum, H. chinense can be relied upon only south of New York. H. floribundum is doing well in California and so will probably the other Mediterranean species.
They thrive in any good loamy soil, and also in sandy soil, if sufficiently moist; most of them prefer partly shaded situations and bloom longer if not exposed to the full sun. They arc, as a rule, short lived plants and ought to be renewed when they show signs of exhaustion. The larger kinds are well adapted for borders of shrubberies and form round rather dense bushes when standing alone, while those like H. calycinum, H. buckleii and H. adpressum are suited for low borders or as a ground-cover, particularly H. calycinum which spreads rapidly by suckers. Many of the low tufted or prostrate species enumerated in the supplementary list are handsome plants for rockeries where the more tender species can be so planted as to be easily protected during the winter. Propagation is by seeds, which germinate readily, the shrubby species also by greenwood cuttings under glass in summer; the creeping kinds as H. calycinum and some herbaceous species also by division and suckers.
Hypericum are suitable for dry, poor soils. They thrive in sunny positions, although some species such as Hypericum calycinum will also tolerate shade.
Hypericum can be propagated by seed or cuttings
- Seed - Surface sow between January and May and put in a cold frame. Pre-soaking in distilled water reportedly increases germination rates.
- Cuttings - Take softwood cuttings from tips of current growth in August and use a sandy compost. Place the cuttings in a cold frame.
Pests and diseases
Hypericum is remarkably resilient to pests and diseases. Very occasionally plants may be infected by rust.
|Standard Cyclopedia of Horticulture|
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.
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
- Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381 -->
- American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432 -->
- Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608 -->