Practical
Plants

Delphinium glaucum

Giant Larkspur

No photo available

Taxonomy and growth

Life cycle
perennial
Height
1.8 m
Flower type
hermaphrodite

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

All parts of the plant are toxic[2]. The plant is most toxic when it is young[6].

Material uses

A parasiticide is obtained from the leaves[2]. It is quite toxic and so is for external use only.

Product or use
Parasiticide

Environment

Range
Western N. America - Alaska to California.
Habitat
Sub-alpine to alpine meadows and streambanks[9]. Meadows, wet thickets, bogs, streamsides and open coniferous woods from sea level to 3200 metres[7].
Light
full sun
Shade tolerance
no shade
Water
moderate
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Drainage
well drained
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - sow March/April in a cold frame or May outdoors[1]. Keep moist and in a shady position until germination takes place[3]. The seed has a limited viability so it should be stored in a sealed container at about 3°c[6]. Temperatures above 15°c inhibit germination[3]. The seed usually germinates in 2 - 9 weeks at 15°c[3]. When they are large enough to handle, prick the seedlings out into individual pots and plant them out into their permanent positions in the summer. Cuttings of basal shoots in April/May, taken before they become hollow at the base, and planted in a cold frame[1]. Division in spring[1] or early autumn[6].

Cultivation

Prefers a rich moist but well-drained soil[4] and dislikes water-logged soils[6]. Requires an open sunny position[5]. This species is hardy to about -20°c[4]. A very variable species, it is divided by some botanists into several closely related species. Apparently because of rather recent and/or incomplete genetic isolation, the degree of differentiation between these species is not such that they can be consistently recognized. Specimens named Delphinium splendens represent plants grown in high-moisture, low-light conditions and may occur as sporadic individuals anywhere from California to Alaska. Type specimens of D . brownii Rydberg, D . canmorense Rydberg, and D . hookeri A. Nelson represent plants grown on relatively dry sites at high latitudes. Plants from dry sites at low latitudes are represented by D . bakerianum Bornmüller and D . occidentale var. reticulatum A. Nelson. Plants with lavender to white flowers are represented by type specimens of D . brownii forma pallidiflorum B. Boivin and D . cucullatum A. Nelson. Type specimens of D . alatum A. Nelson and D . glaucum var. alpinum F. L. Wynd (an invalid name) represent plants growing above or near treeline[7]. Hybridises in the wild with Delphinium brachycentrum to form the hybrid D. x nutans[7]. A greedy plant, inhibiting the growth of nearby plants especially legumes[8].

References

  1. Sanders. T. W. Popular Hardy Perennials. Collingridge 1926-00-00

    ↩1↩2↩3

  2. Schofield. J. J. Discovering Wild Plants - Alaska, W. Canada and the Northwest.

    ↩1↩2

  3. Bird. R. (Editor) Focus on Plants. Volume 5. (formerly 'Growing from seed') Thompson and Morgan. 1991-00-00

    ↩1↩2↩3

  4. Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991-00-00 ISBN 0-330-30936-9

    ↩1↩2

  5. Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990-00-00 ISBN 0-86318-386-7

    ↩

  6. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4

  7. Flora of N. America http://flora.huh.harvard.edu/fna/

    ↩1↩2↩3

  8. Hatfield. A. W. How to Enjoy your Weeds. Frederick Muller Ltd 1977-00-00 ISBN 0-584-10141-4

    ↩

  9. Hitchcock. C. L. Vascular Plants of the Pacific Northwest. University of Washington Press 1955-00-00

    ↩

Edit this page