If you're planning a flower garden and looking for a plant that brings both bright color and intense fragrance, don't overlook English lavender. A variety called "Provence Blue" (Lavandula angustifolia "Provence Blue") is an especially good choice, producing extremely aromatic, deep blue flowers on an attractive, bushy plant. It grows in U.S. Department of Agriculture plant hardiness zones 5 through 9.
Like most lavender varieties, "Provence Blue" has thin, oval, silver-green leaves on stiff, upright stems. An evergreen, the plant has an upright growth habit with a tight branching pattern and produces its flowers from late spring through summer. The deep-blue blossoms are carried high above the plant on stiff stems in clusters that top the stem's last 2 or 3 inches. Tiny individual flowers open slowly over several days, giving off their strong aroma the entire time. When fully grown, this variety is about 20 inches tall with an equal width, somewhat smaller than many other types of lavender.
It's easiest to start a planting of "Provence Blue" lavender from young, nursery-grown plants that were started by propagating cuttings. Plants available in spring or early summer are usually about 4 to 6 inches tall. Although lavender is generally a slow-growing plant, choosing the right spot for new plants and giving them ideal conditions can ensure they grow quickly. When planted in April or May, new "Provence Blue" plants should reach their full height by late July or early August, although the plants will continue to add width until cold weather arrives.
Growing From Seed
You can also start "Provence Blue" plants from seed, sowing them indoors six to eight weeks before the last frost date. Sow seeds in sterile potting soil or soilless mix in peat pots, covering them with only 1/8 inch of soil, because light speeds germination. After the seedlings emerge, move the pots into bright light, keeping the soil barely moist and turning the pots regularly so the seedlings grow straight. When plants have several sets of leaves and danger of frost has passed, place them outdoors in partial shade to harden off for a week or two and then transplant them into their final spot when soil stays above 65 degrees Fahrenheit. The new plants grow slowly their first year but may bloom sparsely before summer's end.
"Provence Blue" lavender grows most quickly in a spot that gets full sun, although it can tolerate a few hours of partial shade each day, especially during the hot afternoon hours. The plant does well in any type of well-drained garden soil, but it does poorly if the soil stays wet for long periods. Adding some fine sand to your soil at planting can improve its drainage if it contains clay and drains slowly. Like all lavenders, "Provence Blue" is tolerant of dry spells after it is established, although giving it regular water during its first season helps it develop a strong root system and grow well.