Lavatera is one of those plants that people see and like immediately, says southern California horticulturist Cristin Fusano, referring to the shrubby perennial Lavatera thuringiaca. When customers see one in bloom, they have to have it, she chuckles. "The flowers and foliage work well in cottage gardens and in wild, relaxed plantings," she adds.
Referring to the annual type, Lisa Crowning, horticulturist at Thompson & Morgan, says it's the large, lustrous, hollyhocklike flowers that really excite people. Lavateras bear attractive silky blooms up to three inches wide, often with delicate contrasting veining. The individual flowers are striking, but it's the profusion of blooms that catches your eye. The palmate, vaguely maplelike leaves are attractive as well.There are 20 to 25 species of lavatera, though only a handful are in cultivation. The group, sometimes referred to as tree mallows, includes annuals, biennials, perennials and shrubs.
Annual Lavatera
Perhaps the most widely grown lavatera is the annual species L. trimestris and its cultivars. Colors range from pristine white 'Mont Blanc' to light pink 'Pink Beauty', and deep pink 'Silver Cup' to bright cherry pink 'Ruby Regis'.
This species reaches from 21 to 36 inches tall and branches from 12 to 18 inches in width. Because of its substantial character and abundant blooms, a group of three or more effectively anchors a border. The pink flowers and green leaves are attractive combined with blue-flowered plants, such as bachelor's buttons or Salvia farinacea 'Victoria', and with silver-foliaged plants like Artemisia 'Silver Mound'.
These annuals, which typically bloom from July to autumn, make useful fillers in perennial gardens, contributing color at a time when many plants are past peak bloom. Although the individual flowers are quite delicate, cut flower spikes are long-lasting and beautiful in bouquets.
How to Grow. Gardeners in all regions can grow this annual, although the plants prefer cool, moist summers. Sow seeds directly in the garden one to two weeks before your last frost date. Pick a sunny location with fertile, well-drained soil. Seeds can germinate in as few as seven days at the optimum 70°F soil temperature, but usually take 15 to 20 days in early spring.
Thin seedlings 12 to 18 inches apart. In short-season regions, sow seeds indoors now and transplant after frost. Lavatera is sensitive to root disturbance: Sow three seeds to a peat pot and thin to the strongest seedling. When it is about four inches high and well hardened-off, plant, peat pot and all, in the garden. The plants require consistent moisture and wilt or drop buds if it gets too hot and dry.
For bouquets, cut spikes with two open flowers. After cutting, several additional buds will open. A cut spike lasts 7 to 12 days.
Perennial Lavateras
The perennials, often called tree mallows, are fast-growing and shrubby in appearance. Perfect in borders, they are also attractive as informal hedges and useful as screens at the back of flower beds.
Actively growing plants from a nursery, or plants started from seed, tend to establish better than bare-root plants purchased through the mail. All need full sun.
Lavatera assurgentiflora. Native to the Channel Islands off California, this mounding evergreen shrub to 15 feet tall resists salt spray and wind. It's useful planted on a hillside or used as a fast-growing screen in an informal, wild garden. The rose to light purple flowers bloom spring through fall and intermittently in winter. They hide somewhat within the large leaves. This tender species tolerates temperatures to 27°F without showing any damage and will survive temperatures to around 18°F, resprouting from the base. It's available in California from nurseries offering native plants.
L. maritima. In coastal and inland valleys of California, L. maritima (also sold as L. bicolor) is quite rugged and especially easy to grow. This species is native to the coast of southern France and is hardy to at least 18°F. The vigorous, branched evergreen shrub grows upwards to 12 feet tall and nearly as wide. The leaves and stems have a soft gray cast. The two-inch flowers, lavender pink veined with dark reddish purple, bloom during warm weather seven to eight months a year -- and year-round near the coast.
One California nurseryman describes L. maritima this way: 'It's a great starter plant for gardeners who don't know what they're doing. It doesn't need or like much fussing." Sun, most soils, and moderate to occasional deep watering suit it well. Cut plants back hard at least once a year and shape lightly as needed. This shrub combines nicely with other low-maintenance, casual plants such as lavender, rosemary, Salvia leucantha and Lantana sellowiana. The species is available at nurseries in California.
L. thuringiaca. Native to the Caucasus region of southeastern Europe, this is the most widely grown perennial lavatera. Plant size and flower color vary by selection. Though shrubby in appearance, this roundish to vase-shaped perennial dies back to the ground each year in cold-winter regions.
Among the varieties, flowers to nearly three inches across range from pale to rich pink. They bloom from summer into fall. Plants generally grow five to six feet tall and equally wide. Branching at the base, they are a bit more compact than L. maritima, with greener leaves and stems.
A popular selection is 'Barnsley', with whitish to pale pink flowers and a darker pink eye. The leaves of 'Rosea' are tinted gray and the flowers are pinky mauve. 'Burgundy Wine' has rich purple-red flowers; 'Bredon Springs' has dusky pink flowers flushed with mauve. (Both are listed as hybrids in some catalogs.)
Lisa Crowning of Thompson & Morgan suggests surrounding perennial lavatera with a lower-growing mat of contrasting color such as white or pink evening primrose, Oenothera speciosa. Or, for a cottage garden look, plant it among tall spiky plants like larkspur.
Lavatera thuringiaca is fast-growing and easy to start from seed. In the garden, it prefers sun and well-drained, fairly fertile soil. Too much fertilizer results in dense foliage and fewer flowers. Cut back each year in fall.
References recommend this perennial for mild-winter zones 7 to 9, but gardeners in zones 3 and 4 report years of success with it. A combination of hot summers and high humidity seems to be hardest on these plants.
Horticulturist Lauren Springer in northern Colorado (winter lows of -30° to -35°F) has had it thriving in her garden for six years. Humidity is low and snow cover is light in her region. In Cokato, Minnesota, west of Minneapolis, Ainie Busse of Busse Gardens also reports success. Busse plants in a sheltered location, and mulches plants in fall with 10 to 12 inches of hay. She believes the mulch plus a dense snow cover protects plants through the winter.
