Colorful primulas are among the first flowers to appear in spring, providing a bright spark to a landscape just coming to life after a long winter. Also called primroses, most primulas are indigenous to light climates. In their natural habitat, primulas prefer woodland conditions — moist, well-drained dirt and semi-shade. Primula includes tens of thousands of species. Primulas are classified into five main types. Most are low-growing plants which top out at 3 to 12 inches, but a couple of reach heights up to 30 inches.
Polyanthus is a large set of primulas marked with clusters of large blossoms in almost every color of the rainbow. Cultivars include “Gold Lace,” with mahogany petals and stone centers, “Penumbra,” with mahogany petals and silver edges, and “Guinevere,” with soft pink, yellow-edged flowers and bronze leaves. More weather-resistant that most primulas, Polyanthus is hardy at U.S. Department of Agriculture plant hardiness zones 3 through 9.
Auricula primulas, suitable for growing in USDA zones 3 through 9, screen leathery, grayish green leaves and clusters of brightly coloured blooms. Auricula is made up of three main types — Alpine primulas with colorful petals and centers of contrasting white or gold, Show primulas, including an assortment of bright-colored flowers, each with a white center encircled with a black band, and a third selection — edge primulas, vigorous plants which exhibit bright blossoms with a sweet scent. Since the blossoms are so showy, Auricula primulas are often grown in containers.
Unlike most primulas, Candelabra primulas are tall varieties with whorled blossoms and long, sturdy stems. The crops often reach heights up to 24 inches. Candelabra primulas include Apple Blossom (P. japonica “Apple Blossom”), in shades of deep pink and crimson, and Oriental Sunrise, (P. japonica “Oriental Sunrise”), at a mixture of colours which include orange, yellow, peach, lavender and mauve. Postford White (P. japonica “Postford White” ) displays pure white blossoms with contrasting yellow centers. Candelabra primulas are suitable for growing in USDA zones 4 through 9.
Juliana primulas (P. Juliae), low-growing plants with bright green leaves, top out at just 3 to 4 inches, with each colorful bloom growing on one stalk. Juliana primulas, suitable for growing in zones 5 through 9, are ideal for woodland places, boundaries or flower beds. Varieties include White Wanda (P. juliae “Wanda Albaan”), a dainty, old-fashioned white primrose with yellow centers, and Footlight Parade (P. juliae “Footlight Parade”), in shades of salmon, orange, apricot and peach.
Acaulis primulas (p. Acaulia or p. Vulgaris) are hybrid varieties with sturdy stems that endure two or three large, rosette-style flowers. Commonly called English primulas, Acaulis primulas are much like polyanthus cultivars. Acaulis primulas, that climb to 8 inches tall, are hardy in USDA zones 3 through 7. Blooms come in shades of white, red, blue, bronze, wine, yellow, brownish, such as the sweet-scented Danova (P. vulgaris “Danova”) along with the rose-colored Belarina (P. vulgaris “Belarina”).