Glaucous Foliage Plants, Conifers, Shrubs, Herbaceous
Cedrus atlantica glauca, over 60 ft., with bluish foliage, is the most impressive of the glaucous conifers and can be pruned to make a broad tree if the garden is small. Among the cypresses there are:
lawsoniana columnaris glauca, usually kept to 20 ft. in British Isles, C.l. Triomphe de Boskoop, deep grey-blue, and C.l. fletcheri, bluish-green, can be kept as a symmetrical dwarf if clipped. Picea pungens glauca moerheimii, 3 ft., s. 3 ft., the blue Colorado spruce, is bright silver-blue and grows very slowly to form a small dense tree.
For covering the ground there are:
Picea pungens procumbens, and also Sequoia sem-pervirens glauca-prostrata (the low-growing form of the gigantic Californian redwood), which grows well in a deep loamin a sunny position and should be planted from September to October or from April to May.
Coronilla glauca, 5 to 9 ft., s. 4 to 8 ft., does particularly well by the sea but it will grow inland in a sheltered corner and produce yellow vetch-like flowers all through the year. The form C. Valentina makes a dwarf bush and has more silvery foliage. Plant in October.
Eucalyptus gunnii, up to 50 ft., s. 6 ft., in Britain, is the hardiest of the family and will succeed in most districts against a south wall in a rather rich soil composed of loam, decayed manure and charcoal. If it grows too high the main stem can be cut and new growth will soon disguise the operation. Plant in spring or autumn.
colensoi glauca, 2 ft., s. 2 ft., is a dense little shrub with blue-grey leaves, H. pageana is similar but with less narrow leaves, and H. pinguifolia, 1 to 3 ft., s. 2 ft., has glaucous rounded leaves rather like those of eucalyptus. H. cupressoides, 3 to 6 ft., s. 4 ft., looks like a small cypress, smells like incense and is covered with tiny lavender flowers in July.
Romneya (Californian tree poppy). This genus has handsome, glaucous, lobed leaves and large white flowers, with conspicuous yellow centres. The following need light soil and a sunny position and should be planted from April to May:
Romneya coulteri, 6 to 8 ft., s. 5 ft., and its improved forms R. hybrida, 3 ft, and Romneya trichocalyx, 5ft.
Dianthus (pinks) have very good glaucous foliage and clumps of them are attractive in the garden even when the plants are not in flower. Pinks grow particularly well in a limy soil.
Eryngium maritimum (sea holly), 1-1/2 ft., has the bluest leaves of all the eryngiums, and will sometimes grow well at the edge of a gravel path.
. This genus has foliage that varies from green to glaucous. Euphorbia biglandulosa, 2 ft., and the smaller E. myrsinites, which are the most blue-grey, are prostrate in habit and never happier than when sunning themselves on a flat stone facing south. Plant from October to March in ordinary soil in dry borders, banks or sunny .
Hosta glauca (syn. Funkia sieboldiana), 1 to 2 ft., has large heart-shaped, blue-green leaves, crinkled and veined to a fascinating pattern. Flowers can be lilac or white.
gennanica, 2 ft., in its many forms has beautiful sword-like glaucous leaves which are handsome when rising beside a path or among plants of rounded shape.
Othonnopsis cheirifolia, up to 1 ft., has glaucous paddle-shaped leaves arranged in layered bunches on each side of its long stems, and fleshy, yellow, daisy flowers. It is useful at the front of the border, in walls or for covering banks, and should be planted in light loamy soil in a warm position in spring or autumn. Often needs protection in winter.
Rudbeckia maxima, 4 to 6 ft., s. 4 ft., with its long glaucous leaves and black-coned yellow flowers is a striking plant when given enough space and a moist position.
Ruta graveolens Jackman’s Blue (rue or herb of grace), 3 ft., with its ferny blue leaves, is the best form of this aromatic plant. It makes a lovely pool of colour and can be used as a low hedge.
spectabile (ice plant), 1 ft., has waxy glaucous leaves which remain attractive throughout the year, and flowers in varying shades of pink. S. roseum (so called because of the colour of its roots), 6 in., has lemon-yellow flowers and is a neat glaucous plant for growing between stones.
Thalictrum glaucum has bold glaucous foliage on 5-ft. Stems, topped with fluffy sulphur-yellow flowers in July.
Tropaeolum polyphyllum, a trailing plant, has long stems ruffled with delicate glaucous leaves and golden flowers. It is a wonderful plant for draping over a bank but is not always easy to establish. Plant from August to November in a warm, sunny position in well-drained soil. Once settled it will reappear regularly each year.