Glandora diffusa, the purple gromwell, syn. Lithodora diffusa, Lithospermum diffusa, is a species of flowering plant in the family Boraginaceae. It is a mat-forming perennial growing to 15 cm (6 in) tall by 60 cm (24 in) or more wide, with dark green, hairy evergreen leaves and masses of blue or white 5-lobed flowers. It is suitable for cultivation in a rock garden or alpine garden.[1]
| Glandora diffusa | |
|---|---|
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| G. diffusa, Osaka Prefectural Flower Garden, Japan | |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Boraginales |
| Family: | Boraginaceae |
| Genus: | Glandora |
| Species: | G. diffusa
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| Binomial name | |
| Glandora diffusa (Lag. ) I.M.Johnst.
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Although there is a variety with white flowers, G. diffusa var. alba,[2] the blue-flowered varieties are most valued in gardens for the intense azure color of their abundant blooms. A number of cultivars have been developed for garden use.[3]
Glandora diffusa is hardy down to −23 °C (−9 °F) (USDA zones 6 - 8),[2] and requires a position in full sun. It needs a well-drained acid or neutral soil, as it is susceptible to root rot. It requires vernalization to flower.[4]
The ancient Greek term lithodora literally means "stone gift", referring to its preferred habitat. Diffusa means "spreading", and refers to the plant's growth habit.[5]
References
edit- ^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 978-1405332965.
- ^ a b Armitage, Allan (1989). Herbaceous Perennial Plants. Athens, GA: Varsity Press, Inc. pp. 385–386. ISBN 9780942375015.
- ^ "results for 'Glandora diffusa'". Royal Horticultural Society. July 2017. Retrieved 6 September 2020.
- ^ "Lithodora diffusa 'White Star' Technical Guide" (PDF). Blooms of Bressingham. Archived from the original (PDF) on 2017-02-24. Retrieved 2017-01-07.
- ^ Coombes, Allen J. (2012). The A to Z of plant names. USA: Timber Press. pp. 312. ISBN 9781604691962.