True blue in the garden
By LINDA STEPHENS-URBANIAK
Mercer Island Reporter Columnist
September 1, 2009 · Updated 12:26 PM
With all the bright yellows, reds and oranges of late summer and fall, the eye longs for a balancing blue. To solve this discrepancy, there are three great flower groups that will bring bright, true blue into the garden.
The Salvias can be annuals or perennials. They need full sun and well-drained soil to do their best. They are drought-tolerant once established.
Salvia farinacea can be sown from seed and will reward you with true blue flowers on strong stems that are coated with a white “farina,” giving a pale silvery appearance. These annuals, which will grow to 18 to 24 inches high, require sun and will attract bees, butterflies and hummingbirds. They are unusual in that if they are cut and hung upside-down to dry, they will retain their blue color.
Salvia ‘Black and Blue’ has anise-scented leaves and will provide the border with bright blue flowers on 3- to 4-foot stems. It is a tender perennial, but if the tubers are protected from moles and voles, it will reward you with blue from mid-summer through fall. Four to six inches of chopped leaves will protect the tuber in all but the worst winters. Emerging foliage needs to be protected with slug bait in the spring.
Nothing will draw attention like Salvia uglinosa. The bright blue flowers are highlighted with white and grow on gray-green stems to almost 6 feet tall. They will grow in almost any soil, but need more moisture than most Salvias. This is a plant to watch carefully, however, because in just the right spot it can spread aggressively.
For small shrubs with bright blue flowers, nothing lights up the fall garden better than Caryopteris. C. clandonensis ‘Dark Knight’ has gray green foliage and the darkest blue flowers of the genera. It blooms on stems 3 to 5 feet tall with a spread of 3 to 4 feet.
‘First Choice’ Caryopteris is a more compact bush, 24 to 30 inches high, with a similar spread. The cobalt blue flowers are present from mid-summer to early fall on silvery green foliage. Another low-growing form is ‘Petit Bleu,’ with deep blue flowers and dark green glossy foliage. It grows to about 2 1/2 feet tall.
‘Sunshine Blue,’ C. indica ‘Jason,’ has bright yellow foliage on shrubs 3 to 4 feet high and wide. It is a late bloomer with amethyst blue blossoms.
All of the Caryopteris group need to be fertilized with a balanced organic fertilizer early in the spring each year. They need well-drained, loamy soil and will soon be gone in heavy, wet clay. They attract bees and butterflies. Since they bloom on new growth, you will be rewarded if you cut the plant back to about 8 inches every spring about the end of February.
One of the finest groundcovers is Ceratostigma plumbaginoides, commonly called Plumbago (but quite different from that tropical plant). It grows from 6 to 8 inches tall and will spread to 18 inches and beyond. It slowly emerges toward the end of May with shiny leaves touched with red around the edges. They slowly turn bright green. Toward the end of August, bright red buds appear, opening to intense blue, five-petaled flowers. It continues blooming until the first frosts when the leaves begin their turn to bright mahogany red. They do well in sun or shade in many different soil types.
Blue can balance out the hot colors of fall. These are just three forms of the many wonderful plants available for the fall garden.
Linda Stephens-Urbaniak may be reached at email@example.com.