The Background for Natural Rock Gardens:

For this purpose, with the restriction of height largely removed, a much wider list may be selected from, and therefore there is no need to present one in detail here.

Those mentioned are more in the nature of examples suggesting what may be used than any attempt at a complete list.

Evergreens:

Arrowhead Norway Spruce (Picea exceha conica): A fine semi-dwarf evergreen, ten or twelve feet

Japanese Umbrella-Pine (sciadopitys verticillata): 13 to 15 feet; distinct, very Japanesque.

Swiss Mountain (pinus Montana): taller-growing form of the well-known Mugho pine.

Pines (Various): Many of the other pines are well suited to background planting for the rockery.

The Jack Pine (P. banksiana); the Shrub Pine (virginiana) and the Limber Pine (flexilis) being especially desirable.

Hemlocks: The hemlocks are, by nature, rock associates, and the happiest of all evergreens to use near the rock garden; prefer a rather moist, peaty soil; may be used in the shade.

The Smaller Evergreensred cedars, junipers, yews, arborvitae, and cypresses (chamaecyparis), are all generally available, if one avoids the artificial-looking colored or too symmetrically shaped horticultural varieties.

The Japanese Temple Cedars, Cryptomeria japonica and lobbi, both of which are very Japanesque in effect; Deodar Cedar (Cedrus deodara) ; Lawson Cypress (Chamaecyparis lanvsoniana) which is hardy to New York; and Moss Sawara Cypress (Cham, pisifera squarrosa), of plumelike foliage, and slow growth, are among the most effective.

Evergreen Shrubs

The introductory remarks above, concerning evergreens, apply equally to the evergreen shrubs.

Almost all of them, if they are too tall to be used within the rockery, may be allowed just over the fence looking in, but care must be exercised to avoid too many varieties or too extensive masses of them; otherwise we may have a show ground of rhododendrons or azaleas instead of a rock garden.

Deciduous Trees and Shrubs:

The deciduous dwarf shrubs are not nearly so essential in rock garden planting as the evergreen sorts, but there are a few which are very desirable and a number may well be used.

Here are a dozen or so of the most important:

Daphne mezereum: Dainty and beautiful; blooms early spring, often again in late autumn. Somewhat sheltered location; usually not over two feet.

Box Barberry (Berberis thunbergi minor): Two to three feet; small yellow flowers and conspicuous berries; hardy to Massachusetts.

Dwarf Birch (Betula nana): Charming little trees; unsurpassed with the dwarf evergreens; about three feet.

Genista: Golden flowers in June; unequaled dwarf shrub for poor, dry soil; easily grown from seed.

Dwarf Huckleberry (vaccinium): All charming, with dainty drooping flowers; grow in dry, sandy soil.

Dwarf Willow (Salix bryacycarpa): Has gray foliage and yellow bark.

S. repens: a creeping form, with silvery leaves.

Rhodora (R. canadensis): A tiny rhododendron, two to three feet tall.

Roses: Several of the species are desirable; among the most dwarf are the Virginia rose (R. lucida), the Bristly rose (R. nitida), and the Pasture rose (R. humilis).

Star Magnolia (M. stellata): A little gem, early, and very hardy.

Viburnum carlesi (Fragrant V.): Taller than many other things in this list, but in every way desirable.

Waxmyrtle (myrica carolinensis): Another plant for poor soils.