Verbena
Fundamental Facts
HARDINESS: Frost tolerant
PREFERRED SOIL pH: Neutral
PREFERRED SOIL TYPE: Well-drained loam
PREFERRED LIGHT: Sun
ATTRIBUTES: Handsome, sprawling plants tipped with dense flower clusters in many colors; for beds, pots, hanging baskets
SEASON OF INTEREST: Early summer to late fall
FAVORITES: 'Silver Anne' for scent; moss verbena Imagination' for pots; V. bonariensis for cutting; V. peruviana as ground cover
QUIRKS: Pinch back stem tips early to encourage branching
GOOD NEIGHBORS: Geraniums, herbs, petunias, roses
WHERE IT GROWS BEST: Sunny, dry locations
POTENTIAL PROBLEMS: Aphids; powdery mildew
CRITTER RESISTANCE: Excellent
SOURCE: Bedding plants, cuttings
DIMENSIONS: 8 in-4 ft (20.3 cm-1.2 m) tall, spreading 2 ft (0.6 m) in diameter
Verbena in the Landscape
If it has any faults at all, verbena could only be accused of working too hard and producing an overwhelming crop of colorful flowers. Verbena blooms throughout the summer in full sun despite dry, parched soil and inconsistent watering, and can play several roles. As a mainstay in containers, it sends out numerous stems swooping over the sides of pots, which brings texture to the display. When used as bedding plants, verbenas elegantly grow together to fill a garden with color or cover the ground below tall, bare-stemmed, "leggy" plants. They can also be persuaded to interweave with foliage or flowering plants, with no maintenance needed.
Verbenas are available with white, pink, blue, purple, red, and two-toned flowers. The flower heads form at the ends of the stems, with numerous tiny, brightly colored flowers clustered into a tight mound that resembles a clump of snowflakes. At night, varieties like 'Silver Anne' send their sweet perfume roaming. Through the day, butterflies and hummingbirds court the nectar-rich flowers.
Except for occasional visits from aphids, which can be rinsed off or controlled with insecticidal soap, few pests bother care-free verbenas. Even deer shy away, and verbenas laugh in the face of drought. For maximum performance, spent flowers should be removed by clipping back older stems, which also encourages the emergence of new branches. But even when left to their own devices, verbenas just keep performing.
A Flower of Many Faces
The most popular verbenas by far are the annual verbena hybrids that form loose mounds of slightly felted, deep green leaves and 3 in (7.6 cm) wide flower clusters. But they're not the only game in town. Consider moss verbena (Verbena tenuisecta), with its thin, lacy leaves on trailing stems, making it perfect as a vertical accent in containers. 'Imagination', with its violet-blue flowers, is a particularly impressive variety. Purple-top verbena (V. bonariensis) has an entirely different posture. It stands bolt upright, balancing its clusters of purple blooms on stiff, sparsely clad stems, up to 3-4 ft (1-1.2 m) in height, making it ideal for interweaving with perennials and cutting for bouquets. For a good creeper at the front of a bed or a temporary ground cover, try Peruvian verbena (V. peruviana), a low-growing type with scarlet flowers. These accommodating species can also be grown as perennials in Zones 7 to 9.
Increasing the Bounty
Verbenas are difficult to start from seed, so you're better off buying them as bedding plants, but they are easy to root from cuttings. In fact, if you pin a stem to the soil with a hairpin or bent piece of wire, it will make roots at die point of contact within a couple of weeks. You can then sever the rooted stem from the mother plant and plant it separately.