Few plants can top lavender (Lavendula spp.) for attractive, aromatic blossoms that are good garden accents and useful cut flowers. They can also be dried for use in potpourris and other fragrant mixtures. Several different types of lavenders are commonly cultivated, with each type available in varieties that come in all sizes, from tall plants useful in the back of a border to smaller cultivars that work well in the front of beds or borders.
Lavender plants can be divided into several groups. English lavender (Lavandula angustifolia) grows in U.S. Department of Agriculture plant hardiness zones 5 through 9 and has furry gray-green leaves and spikes of purple or pink fragrant flowers. Spike lavender (Lavandula latifolia), also called broadleaved lavender, is a shrubby plant that grows in USDA zones 6 through 9, while plants called intermediate lavenders or lavandins (Lavandula x intermedia) are hybrids between these two types and generally grow in zones 5 through 8.
Some types of lavender are available in different cultivars, with a number of these being quite tall. For example, a variety of English lavender called 'Royal Velvet' can reach a height of 3 feet or more, with dark purple, velvetlike flowers. Like most English types, it's usually about 4 feet wide. Many hybrid lavenders, or lavandins, are even taller; for example, a variety with light blue flowers that blooms in late summer, called 'Fred Boutin,' is 36 to 40 inches tall, while 'Seal,' with medium-blue flowers, can be 60 inches tall.
Certain lavender varieties are modest in height and fit well into many different spots in a home garden. These include common spike lavender, which is a shrubby plant that's only about 16 inches tall. A variety of hybrid lavender, or lavandin, called 'Provence' is about 2 feet tall and wide, although it might be taller and wider when grown under ideal conditions -- full sun and in well-drained soil. Another type of lavender called French lavender (Lavandula stoechas) is also quite compact, growing as a shrub that's 1 to 3 feet tall and wide. It grows in USDA zones 8 through 9 and requires full sun for best growth.
A few varieties of English lavender are medium-tall and well-suited to mixing with other compact plants in beds and borders. A cultivar called 'Nana Alba' is a good example that's only about 24 inches tall and also has unusual white flowers. Another variety called 'Melissa' has pink flowers and is only 18 to 24 inches tall, while one called 'Lodden Blue' has deep purple flowers and is equally short, also 18 to 24 inches tall.
Promoting Best Growth
In addition to lots of sun and well-drained soil, lavender plants thrive in slightly dry conditions and don't tolerate soggy, constantly wet soil and high humidity. They do well in raised beds, along a stone wall or at the top of a slope -- all spots that tend to dry quickly after rain. Planting lavender in a small mound can also help ensure good drainage. Each fall, mix a small handful of phosphorus-rich bone meal into the top inch of soil around each plant to promote good growth the following spring.
Pruning lavender a few times during the growing season promotes strong branching, producing a bushy plant with lots of flower buds. Clean your pruning tools by wiping blade with rubbing alcohol between cuts to prevent the spread of disease.