AUBRIETA: THE PURPLE ROCK CRESS
Fine Plants for Spring Bloom in the Rock Garden and at the Front of the Flower Border
(Aubrie'ta). Hardy, perennial, more or less evergreen, low-growing plants which bear a profusion of bloom in early spring. They are invaluable in the rock garden and wall garden, and as edging to flower borders, and groundwork for taller plants in spring flower beds. Unfortunately, they are apt to be rather short-lived where hot summers prevail. Young plants seem better able to withstand adverse conditions than are older ones; hence it is a good plan to raise some new plants each year. They may, in fact, be successfully treated as biennials. They are widely distributed in mountainous regions along the coast of southern Europe and Persia and belong to the Mustard family, Cruciferae. Aubrieta (previously spelled Aubrietia) is named after Claude Aubriet, a French painter of natural history subjects.
When to Plant—Suitable Soil. The Aubrietas like rather light, well-drained soil; heavy soil must be made suitable by adding leaf mold and sand; otherwise the plants are liable to die off or become patchy in winter.
They need a sunny or only slightly shaded position and may be planted in fall or spring.
Ideal Wall Plants. Where summers are not excessively hot, Aubrietas are ideal plants for draping a garden wall; if planted on top of the wall or in crevices between the stones in well-drained, sandy, loamy soil, they spread and furnish a delightful show of bloom in spring.
When to Sow Seeds. Aubrietas can be increased in several ways. Seedlings are raised by sowing seeds in boxes (flats) of sandy, loamy soil, placed in a cold frame or slightly heated greenhouse in March—April. The seedlings are transplanted 2 in. apart in other boxes of similar soil and when well rooted are planted in nursery beds or in cold frames until large enough for their final positions. After blooming, old plants may be lifted and separated into rooted pieces for replanting.
How to Take Cuttings. Cuttings should be inserted as soon after flowering as possible in boxes of sandy soil placed in a frame kept closed. If a stock of old plants exists, the flowering shoots should be cut off when the blooms have faded and a mixture of leaf mold and sand worked in among the shoots: the latter will then form roots freely and, if removed and transplanted in autumn, will bloom the following spring.
In Europe many beautiful named varieties of the Italian A. deltoidea are grown, but in America it is more usual to raise plants from seeds. Seedlings vary considerably; good forms may be selected for vegetative propagation.
AUCUBA (Aucu'ba). Evergreen shrubs, 5-6 ft. high, with large, glossy, laurel-like green or variegated leaves, and clusters of red fruits, each of which contains a single seed. The flowers are small, not showy, and male and female flowers are borne on different plants. They grow wild in Japan, China, and the Himalayas, and belong to the Dogwood family, Cornaceae. The word Aucuba is derived from the Japanese name of the shrub, aokiba. Aucubas will live outdoors in very sheltered locations in the vicinity of New York City, but are generally hardy only where milder winters are the rule.
As Pot Plants. Aucubas are very satisfactory for cool rooms and sun porches and are good for growing in large pots or tubs as terrace plants. They thrive in any ordinary soil. From spring through fall they need plenty of water but should be kept drier in winter.
Will Thrive Beneath Trees. They thrive in any good garden soil, either in full sun or in partial shade, and withstand a good deal of dryness at the roots; they are among the best of all evergreens for planting beneath the shade of trees. They will, in fact, thrive where many other plants and shrubs will perish, even beneath the shade and drip of large trees, provided the soil is not quite impoverished. Propagation can be effected by means of cuttings.
When to Take Cuttings. If terminal shoots, with two or three side branches, are inserted in a propagating case in a greenhouse—temperature 60 degrees during spring or summer—they form roots in a few weeks and may soon be planted out of doors. Similar cuttings will also form roots in August in a cold frame, or even out of doors.
Sowing Seeds and Layering. Seeds, cleansed of the outer fleshy pulp, may be sown as soon as ripe in autumn, in pots of sandy soil in a greenhouse—temperature 50-55 degrees. Fresh plants are sometimes raised from branches layered in spring, and large shrubs can be divided in September. As cuttings are in every way satisfactory,
it is rarely necessary to resort to any other means of raising stock.
Very little pruning is required, for young plants grow naturally into shapely bushes; overgrown plants should be cut back in March or April. Planting may be done in spring or fall.
Green and Variegated Leaves. Aucuba japonica has green leaves, but the varieties with variegated leaves are chiefly grown. A male plant should be planted among every six female plants to ensure a good crop of berries. Two of the best varieties with variegated—green and pale -yellow —leaves are variegata, the Gold-Dust Tree, and picturata (also called latimaculata and aureomaculata).