
Hypericum calycinum
Hypericum calycinum
Safety & Hazards
None known
Cultivation Details
Easily grown in any reasonably good well-drained but moisture retentive soil.[1] Succeeds in dry soils[2] and in chalky soils[3]. Grows well in heavy clay soils. Succeeds in sun or shade but flowers better in a sunny position[3]. Grows well even in the shade of tall trees[1, 4, 5]. Tolerates poor soils and also drought when it is established[6]. A very cold-hardy plant, tolerating temperatures down to about -25°c[6]. A very ornamental but very invasive plant, spreading by means of stolons[1, 7]. Seldom sets seed in Britain, probably due to our wet autumns[7]. Plants are often afflicted with rust disease[7, 2]. Plants in this genus are notably resistant to honey fungus[2].
Propagation
Seed - sow spring in a greenhouse and only just cover the seed. Germination usually takes place within 1 - 3 months at 10°c. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings of half-ripe wood 10 - 12 cm with a heel, mid summer in a frame. Plant out in the following spring[2]. Cuttings of mature wood, 12 - 17cm with a heel, autumn in a sheltered position outdoors. Plants root by the spring. Good percentage[8]. Division in spring as new growth commences[8]. Very easy, larger clumps can be replanted direct into their permanent positions, though it is best to pot up smaller clumps and grow them on in a cold frame until they are rooting well. Plant them out in the spring. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Hypericum+calycinum>
Pollinators
Insects, Self
References
- [1]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
- [2]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
- [3]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
- [4]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
- [5]Shade Plants for Garden and Woodland. — Brown. ↩︎
- [6]Shrubs. — Phillips. R. & Rix. M. · Pan Books · 1989 · ISBN 0-330-30258-2 ↩︎Excellent photographs and a terse description of 1,900 species and cultivars.
- [7]Ornamental Shrubs, Climbers and Bamboos. — Thomas. G. S. · Murray · 1992 · ISBN 0-7195-5043-2 ↩︎Contains a wide range of plants with a brief description, mainly of their ornamental value but also usually of cultivation details and varieties.
- [8]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
- [9]Plants for Ground Cover — Thomas. G. S. · J. M. Dent & Sons · 1990 · ISBN 0-460-12609-1 ↩︎An excellent detailled book on the subject, very comprehensive.
- [10]The Dry Garden. — Chatto. B. · Dent · 1982 · ISBN 0460045512 ↩︎A good list of drought resistant plants with details on how to grow them.
- [11]Ground Cover Plants. — Royal Horticultural Society. · Cassells. · 1989 · ISBN 0-304-31089-1 ↩︎A handy little booklet from the R.H.S.