Difference between revisions of "Ledum"
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| + | Ledum (''ledon'', ancient Greek name of Cistus). ''Ericaceae''. Labrador Tea. Ornamental shrubs grown for their handsome white flowers and evergreen foliage. | ||
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| + | Leaves alternate, short-petioled, entire: flowers rather small, 1/3 - 1/2 in. across, long-pedicelled, in terminal, umbel-like racemes; calyx-lobes and petals 5, spreading; stamens 5-10: caps, nodding, 5-celled, separating from the base into 5 valves, with many minute seeds. Four species in the arctic and cold regions of the northern hemisphere, all found in N. Amer. One of the few ericaceous genera with polypetalous flowers. The leaves. contain a volatile oil, with narcotic properties; the leaves. of ''L. groenlandicum '' are said to have been used during the War of Independence as a substitute for tea, hence the name "Labrador tea." | ||
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| + | These plants are low, sometimes procumbent, shrubs with evergreen narrow leaves fragrant when bruised, and with handsome white flowers appearing in early summer. They are all hardy North, and well adapted for borders of evergreen shrubberies or for planting in swampy situations. They thrive as well in sunny as in partly shaded situations, and prefer a moist, sandy and peaty soil. Transplanting is easy, if the plants are moved with a sufficient ball of earth. Propagation is by seeds sown in spring in sandy peat and treated like those of azalea and rhododendron, the young plants growing but slowly; increased also by layers and division. | ||
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Revision as of 04:52, 10 July 2009
Read about Ledum in the Standard Cyclopedia of Horticulture
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Ledum (ledon, ancient Greek name of Cistus). Ericaceae. Labrador Tea. Ornamental shrubs grown for their handsome white flowers and evergreen foliage. Leaves alternate, short-petioled, entire: flowers rather small, 1/3 - 1/2 in. across, long-pedicelled, in terminal, umbel-like racemes; calyx-lobes and petals 5, spreading; stamens 5-10: caps, nodding, 5-celled, separating from the base into 5 valves, with many minute seeds. Four species in the arctic and cold regions of the northern hemisphere, all found in N. Amer. One of the few ericaceous genera with polypetalous flowers. The leaves. contain a volatile oil, with narcotic properties; the leaves. of L. groenlandicum are said to have been used during the War of Independence as a substitute for tea, hence the name "Labrador tea." These plants are low, sometimes procumbent, shrubs with evergreen narrow leaves fragrant when bruised, and with handsome white flowers appearing in early summer. They are all hardy North, and well adapted for borders of evergreen shrubberies or for planting in swampy situations. They thrive as well in sunny as in partly shaded situations, and prefer a moist, sandy and peaty soil. Transplanting is easy, if the plants are moved with a sufficient ball of earth. Propagation is by seeds sown in spring in sandy peat and treated like those of azalea and rhododendron, the young plants growing but slowly; increased also by layers and division.
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| Rhododendron subsect. Ledum | ||||||||||||
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 Rhododendron tomentosum (Ledum palustre) | ||||||||||||
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Ledum is a genus name formerly widely recognised in the family Ericaceae, including 8 species of evergreen shrubs native to cool temperate and subarctic regions of the Northern Hemisphere and commonly known as Labrador Tea.
Recent genetic evidence has shown that the species previously treated in this genus are correctly placed in the genus Rhododendron, where they are now treated as Rhododendron subsect. Ledum.
Because some of the species names used in Ledum could not be used in Rhododendron (the names already having been used for other species already in this large genus), new names had to be coined for them.
- Species
The species formerly listed in Ledum, with their current accepted names in Rhododendron, are:
- Ledum decumbens = Rhododendron subarcticum Harmaja
- Ledum glandulosum = Rhododendron neoglandulosum Harmaja
- Ledum groenlandicum = Rhododendron groenlandicum (Oeder) Kron & Judd
- Ledum hypoleucum = Rhododendron hypoleucum (Kom.) Harmaja
- Ledum macrophyllum = Rhododendron tolmachevii Harmaja
- Ledum palustre = Rhododendron tomentosum Harmaja
- Ledum palustre var. diversipilosum = Rhododendron diversipilosum (Nakai) Harmaja
- Ledum subulatum = Rhododendron subulatum (Nakai) Harmaja
- Hybrids
One natural hybrid also occurs:
- Ledum columbianum = Rhododendron × columbianum (R. groenlandicum × R. neoglandulosum)
Uses
The Athabascans use it the leaves to prepare a tea-like beverage, hence the common name. It is also a traditional medicine among them for weak blood, colds, tuberculosis, dizziness, stomach problems, heartburn and hangover. Some people chew the raw leaves because they like the taste. Others use Labrador Tea to spice meat by boiling the leaves and branches in water and then soak the meat in the tea. The meat may also be boiled directly in the water with the stems and leaves. This spice is said to be especially good for strong-tasting meat, such as brown bear meat that has a fishy taste.
In large doses, Labrador Tea can cause drowsiness, stomach ache, and act as a laxative. Use in moderation. Ledum glandulosum ('Western Labrador Tea', 'Trapper's Tea') becomes toxic if cooked for long periods in a closed container (citation needed). Labrador Tea grows slowly, but, as an evergreen, is available year-round. Users should take care not to over-harvest leaves from any single plant.
Ledum grows together with some poisonous plants such as Bog-laurel and Bog-rosemary.
References
1. Kron, Kathleen A. & Judd, Walter S. (1990) Phylogenetic Relationships within the Rhodoreae (Ericaceae) with Specific Comments on the Placement of Ledum Systematic Botany (1990), 1S(1): pp. S7-68
2. Harmaja, Harri (1990) New names and nomenclatural combinations in Rhododendron (Ericaceae) Ann. Bot. Fennici 27:203-204
3. Harmaja, Harri (1991) Taxonomic notes on Rhododendron subsection Ledum (Ledum, Ericaceae), with a key to its species. Ann. Bot. Fennici 28: 171-173.
6. Kihlman, Bengt A. (2004) Hybrids Between Ledums and Lepidote Rhododendrons. Journal of the American Rhododendron Society 58(2):74-81
