How to grow Delphiniums (del-fin-e-um)
From the Greek dolphin, a dolphin, the flowerbuds having some resemblance to that sea creature (Ranunculaceae). Larkspur. The genus consists of annual, biennial and herbaceous perennial plants, mostly hardy and showy plants for border cultivation, with some dwarf species suitable for the rock garden.
Perennial D. brunonianum, 1-11 feet, light purple, June and July, western China. D. cardinale, 2-3 feet, bright red, July and August, California, somewhat tender. D. denudatum, 2i feet, yellow and blue, summer, Himalaya. D. elatum, 2-3 feet, blue, June, Alps to Pyrenees eastwards, the plant from which most garden delphiniums have been derived. D. formosum, 3 feet, purple-blue, August, Caucasus, Asia Minor. D. grandiflorum (syn. D. chinense); 1-3 feet, violet-blue or white, long spurred, summer, Siberia. D. nudicaule, 1-1i feet, red and yellow, April to June, California. D. speciosum (syn. D. caucasicum), 6 inches-2 feet, blue and purple, summer, Himalaya. D. tatsienense, 1 feet, violet-blue, July, Szechwan. D. vestitum, 2 feet, pale and deep blue, summer, northern India. D. zalil (syn. D. sulphureum), feet, lemon-yellow, summer, Persia, requires a well-drained soil.
Cultivation Sow annual varieties in a sunny, open border in April where they are to flower, or in boxes of light soil under glass in March in a temperature of 55°F (13°C). Prick out seedlings when large enough to handle and transplant in the open in May. Perennials should be planted out in the spring or autumn in beds of rich, deeply cultivated soil ; dwarf varieties are suitable for rock gardens. Feed with liquid manure in the early summer. Lift and replant every third year. Propagation of perennial varieties is by means of cuttings of young shoots in early spring, inserted in sandy soil in pots in a shaded propagating frame, or by seeds sown in the open ground in late spring or under glass in spring.
Cultivation of modern hybrid delphihiums
Fast-growing plants, delphiniums require a deeply-dug, rich soil with adequate drainage. A medium loam is preferable to a light sandy soil. Where the soil is light dig in deeply plenty of compost or old farmyard manure before planting and during the summer a mulch of garden compost is excellent. Nitrogenous fertilisers should be used with care as they may only result in producing weak stems. If the stems are cut back immediately after flowering a second crop of spikes may be produced, but these should only be encouraged with strong-growing varieties.. Adequate moisture will be required to produce this second crop during what may be hot, summer weather. Slugs can be a menace with the tender young delphinium shoots, especially in the early spring, so precautions should be taken with slug pellets or other repellents. Varieties that grow to about 4-5 feet in height are more suitable for small gardens than those that tower to 7 feet or more, and they are less liable to damage by summer gales. Pea sticks, brushwood or twigs can be used to support the young growths but these should be put in position around the plants in good time so that the stems grow up through them. This is often left too late with the result that the tender stems get broken when the sticks are being pushed into the soil. Staking for exhibition spikes must be carefully done, using one stout cane to each spike. When growing the large flowering varieties it is usual to restrict one-year-old plants to one spike and two-year-old plants to two or three spikes. Pea sticks, however, provide adequate support for the lighter, less tall graceful belladonna types of delphinium, with their branching stems, which are also so attractive for floral arrangement. Exhibition spikes should be straight, tapering and well filled with large circular florets but not overcrowded, and bearing few laterals. The foliage should be clean, healthy and undamaged. Immediately spikes are cut they should be placed in deep containers filled with water and stood in a cool, but not draughty place. There they should remain for some hours or overnight. Each stem should be wrapped in a large sheet of tissue paper (30 x 40 inches) before being taken to the show. A further step to ensure that the spike does not flag is to turn it upside down, immediately before final staging, fill the hollow stem with cold water and plug with cotton wool.
As they are easily raised from seed the delphinium has been of much interest to the plant breeder who has produced many stately varieties. The era of immense spikes has passed its zenith and the trend is to develop a range of hybrids not exceeding about 4 feet in height. These are of much more general use in gardens which are ever becoming smaller, but more numerous. From the glorious shades of blue the colour range has been extended from white and cream through pink, carmine, mauve, lavender, purple and violet. Now, thanks to the work done by Dr Legro, the celebrated Dutch hybridist, the range includes shades of cerise, orange,
peach and tomato-red. Our garden hybrids have been mainly derived from Delphinium elatum, a natural tetraploid species, but Dr Legro succeeded in overcoming the sterility barrier when he made a number of species crosses at diploid level, tetraploided the resulting plants and then successfully married them to hybrid elatums (see Plant breeding). The rediscovery of the white African species, D. leroyi, which has a freesia-like fragrance, also opens up pleasing possiblities. First crosses at diploid level have shown that this quality is not recessive, so hopes are high, but all this work takes time. In this country Dr B. J. Langdon has also been working on these problems and during the next few years we should see a truly remarkable range of hybrid delphiniums.
Recommended tall varieties 'Alice Artindale', light blue, 6 feet; 'Ann Page', deep cornflower blue, 54 feet; 'Bridesmaid', silvery-mauve, white eye, 7 feet; 'Charles F. Langdon', mid-blue, black eye, 64 feet; 'Daily Express', bright sky-blue, black eye, 6 feet; 'Janet Wort', pure white, 64 feet; 'Jennifer Langdon', pale blue and mauve, 54 feet; 'Mogul', rosy-purple, 64 feet; 'Purple Ruffles', deep purple, overlaid royal blue, 5 feet; `Royalist', deep blue, 6 feet; 'Silver Moon', silvery-mauve, white eye, 54 feet; 'Swanlake', pure white, black eye, 5 feet.
Shorter-growing varieties 'Blue Bees', pale blue, 4 feet; 'Blue Tit', indigo blue, black eye, 34 feet; 'Blue Jade', pastel blue, dark brown eye, 4 feet; 'Cliveden Beauty', pale blue, 4 feet; 'Naples', bright blue, 4 feet; 'Peter Pan', deep blue, 34 feet; 'Wendy', gentian-blue, 4-5 feet, the most popular of the belladonna type.
The Pacific Hybrids raised in America, growing 4-6 feet tall, include `Astolat', lilac and pink; 'Black Knight' series, shades of violet; 'Blue Jay', mid-blue; `Cameliard' series, lavender shades; 'Elaine', rose-pink; 'Galahad' series, whites; 'Guinevere' series, shades of
From the Greek dios, a god or divine. anthos, a flower, divine flower, flower of Jupiter or Zeus (Caryophyllaceae). A large genus of hardy annual, biennial and perennial plants, which falls into three main groups: pinks, carnations and dianthus proper. The greatest number of species come from the Balkans and Asia Minor, some from the Iberian Peninsula and North Africa, a few from China and Japan and two are natives of the British Isles. Many plants in the genus are very fragrant with a unique perfume, predominantly clove, strongest among the pinks and carnations. Many of the dwarf kinds are excellent rock garden plants; the taller kinds are suitable for the front of sunny borders, banks or other places.
Species cultivated (All are perennials unless otherwise stated) D. x allwoodii, 6 inches-2i feet, very variable in colour, single and double, summer, hybrid. D. alpinus, 3 inches, rose-red, May and June, D. arvernensis, 4-6 inches, clear pink, May and June. D. barbatus, Sweet William, 6 inches 1 feet, perennial usually grown as a biennial, variable in colour, summer. D. x boydii, 3-6 inches, rose-pink, May and July. D. carthusianorum, 1-1i feet, rose-purple, June to August. D. caryophyllus, carnation, clove pink, picotee, 9 inches-3 feet, red, but very variable in cultivation, parent, with D. chinensis, of annual carnations and Chinese and Indian pinks. D. chinensis (syn. D. sinensis), Chinese or Indian pink, 9 inches, annual, variable in colour, summer. D. deltoides, maiden pink, 6 inches, purple to crimson, spotted and striped, summer, native; vars. albus, white; erectus, rich red. D. fragrans, 2 feet, white, summer, D. gratianopolitanus (syn. D. caesius), Cheddar pink, 1 foot, pink, May and June; vars. albus, white; flore-pleno, double or semi-double. D. haematocalyx, 4-6 inches, bright pink, July. D. knappii, 1 foot, pure yellow, July and August. D. microlepis, 2-3 inches, pink, flowers small, spring, scree plant. D. monspessulanus, 6-12 inches, pink, summer. D. musalae, 2 inches, bright pink, spring, scree. D. myrtinervis, 2-3 inches, pink, small, spring. D. neglectus, 3 inches, rose-red, June, dislikes lime. D. nitidus, 6 inches-2 feet, rose-pink, July and August. D. noeanus, 6-8 inches, white, July and Dicentra spectabilis, the Bleeding Heart or Lyre Flower, is a summer-flowering hardy perennial for the sun or shade. Its pendant flowers resemble lanterns hung along a cord.
August. D. petraeus (syn. D. kitaibelii), 8-12 inches, pink, June; var. albus, 6 inches, double white. D. pindicola, 2 inches, deep pink, summer, scree. D. plumarius, pink, Scotch pink, 1 foot, variable in colour, May to July. Parent of the garden pinks. D. squarrosus, 1 foot, white, summer. D. sternbergii, 6 inches, rose-red, June, D. strictus, 6 inches, white, June and July. D. subacaulis, 3 inches, rose-pink, June to August.
Cultivars are numerous. Those of species described above include 'Ariel' ('Crossways'), 4-6 inches, cherry-red, July and August; 'Baker's Variety', 6 inches, large, deep pink, June and July; D. deltoides 'Brilliant', 6 inches, crimson, summer, and 'Huntsman', 6 inches, bright red, June and July; 'Charles Musgrave', 9 inches, white with green eye, summer; 'Cherry Ripe', 6-9 inches, rose-red, summer; D. gratianopolitanus 'Prichard' s Variety', 4-6 inches, rose pink; 'La Bourboulle', 3 inches, deep pink, summer, and 'Double Ruby', 9 inches, summer; 'F. C. Stern', 6 inches, rosy-red, June to September; 'Fusilier', 3 inches, shining crimson, summer; 'F. W. Millward', 9 inches, double pink, summer; 'Highland Queen', 1 foot, deep rose, summer; 'Holmsted', 6 inches, soft pink, summer; 'Inchmery', 1 foot, soft pink, double, summer; 'Isolde', 9 inches, pink and white, double, summer; 'Len Hutton', 1 foot, claret-red, edge laced white, summer; 'Little Jock', 4 inches, rose-pink with darker eye, semi-double, summer; 'Little Jock Hybrids', various colours; 'Margaret Curtis', 1 foot, white, crimson zone, summer; 'Mars', 4 inches, rich red, double; 'Spencer Bickham', 4 inches, deep pink, summer; 'Sweet Wivelsfield' (D. x allwoodii x D. barbatus), 18 inches, half-hardy annuals in many bright colours, summer; 'Windward Rose', 6 inches, light rose, summer.
Cultivation Sharp drainage and preferably a limy soil in a sunny position is needed for most dianthus, except perhaps D. alpinus which likes less sun and tolerates an acid soil fairly well, and D. neglectus which dislikes lime. All do well in sandy loam. When the alpine species are grown in pots in the alpine house a compost ensuring brisk drainage but at the same time sufficiently retentive of moisture is needed. Make it up of 2 parts of coarse sand or crushed gravel, 2 parts of leafmould or spent hops, 1 part of loam and a scattering ,of bonemeal. Cover the surface of the pots with limestone chip-pings for attractiveness, to present the plant as a perfect cushion and to guarantee surface drainage. Propagation is from seed for annual and biennial kinds and those species that set seed, or by pipings and cuttings taken immediately flowering ends, and inserted in pure sand round the edges of a pot and protected until rooting has taken place.