Plant a rocket in your garden for evening aroma

When scientists in the 1600s began firing projectiles made of a cylindrical tube filled with flammable or explosive material, they noted its shape was similar to a thread bobbin or distaff and used the Italian word for distaff, “rocchetto,” to describe these new “rockets.” Italian also gives us another rocket, this one in the garden. Sweet rocket (Hesperis matronalis) is a biennial herb that is hardy in USDA Zones 3-9.

Rocket is the flower of deceit, so called because it emits its fragrant perfume only in the evening. The plant is traditionally used as a gland stimulant and even an aphrodisiac. Young leaves can be picked while still tender, before the flowers appear, and are excellent in salads or lightly sauteed in olive oil. The plants burst into bloom with masses of pink, purple and white flowers in the spring. The flowers attract moths, and the plants attract beneficial insects. The blossoms look like garden phlox but are really part of the mustard family. Garden phlox blooms have five petals with leaves opposite one another, whereas sweet rocket has four petals and alternating leaves.

You can sow sweet rocket seed directly into the garden after all danger of frost has passed in spring. These flowers prefer moist, rich, well-drained soil that is neutral to alkaline pH. Press the seeds into the soil surface and barely cover them with soil; they need light to germinate. Sweet rocket grows best in full sun to light shade. Thin the plants to stand about a foot apart. Keep the soil moist but not soggy with about 1 inch of water each week. You can also sow seeds indoors 6-8 weeks before setting the plants out into the garden. Every spring, you can fertilize the flowerbed with a balanced organic, granular fertilizer or add a few inches of compost to the soil.

The 4-foot-tall plants are great along the back of a flowerbed. They sprout long-stemmed blossoms that make excellent cut flowers. Cut the flower stalks when florets are just 3/4 of the way opened. Plant Hesperis matronalis mixed in with lupines and oriental poppies, which flower at the same time.

Sweet rocket sets seeds and self-sows readily but is not generally invasive. That said, four states (Colorado, Connecticut, Massachusetts and Wisconsin) prohibit it as an invasive weed. The seeds are available from mail-order nurseries and are not prohibited in Delaware. If you do not want it to self-sow, you can cut off the dead flower heads before they set seed. Because it grows narrow and tall, sweet rocket is useful as a flowerbed filler.

As a biennial, once it’s established, you will have flowers every year, as some bloom this year, and others bloom next year.

Plant sweet rocket in a place you can enjoy it, and your garden will play coy all day only to burst into perfume after the sun goes down. Your spirits will soar, perhaps like a rocket.