Two-year Wonders

Biennials: They may have an unusual life cycle, but they're still beautiful and quite willing to return.

July 11, 1999|By Ann Egerton | Ann Egerton,Special to the Sun

Biennial plants aren't particularly distinctive looking, but they certainly have distinctive life cycles. While annuals last for one season and perennials give years of pleasure, the biennial, as its name suggests, has a two-year cycle.

The first year it produces a leafy base or rosette, which winters over; the second year it forms a flower, which, later in the season, develops visible seed pods. Most biennials produce many, many seeds and reseed themselves easily. That is their insurance of perpetuity.

The gardener should keep several of the green rosettes each fall to keep the plant going in the garden. Sometimes the blooming cycle may leap-frog over the plain rosette cycle, thereby bearing flowers every year. It's not surprising, however, that it's hard to sell biennials in garden centers since they're not reliable annual bloomers. A pot of just first-year foliage is not an enticing seller, and you must wait another year to see if it comes back.

There are roughly 20 flowering biennials in our region. It's almost as if their existence is a never- ending horticultural experiment. Examples of biennials include Oenothera glazioriana (evening primrose), Angelica gigas, Digitalis purpurea (foxglove), Campanula medium (Canterbury bells), Lunaria (money plant), Myosotis alpestris and Myosotis sylvatica (forget-me-nots), Dianthus barbatos (sweet William), Alcea rosa (single hollyhock) and Verbascum bombycyferum (yellow mullein).

In the maybe category -- maybe they're biennials, maybe they're perennials -- are Daucus carota (Queen Anne's lace) and Hesperis matronalis (sweet rocket).

One quality that these plants share -- with the exception of Angelica gigas, whose tall, burgundy bloom flowers in August -- is that they blossom in early spring or summer, thereby having ample time to set their seeds and even germinate new plants before cold weather. They also tend to produce flowers that are straight up. Another quirky, sometimes puzzling trait is that their new seedlings can pop up in the strangest places, often quite far from the original plant.

The most unusual seed pods may belong to Lunaria (money plant or honesty plant). While its late-April bloom is deep pink and looks like a small phlox, its seed pod in the fall is round, silvery and translucent. Because it looks a little like a silver coin, it is often called money plant.

In addition to notable herbaceous flowers, some vegetables and herbs are biennials. The regular carrot, parsnip and cabbage each have a two-year growth cycle. Each, if left in the ground, overwinters and then produces a flower the second year. The cabbage cracks first to achieve this. Biennial herbs include parsley, caraway and Angelica. Angelica, whose full botanical name is Angelica Archangelica (herb of angels) is related both to the flower Angelica Gigas and to the parsnip. It grows to about six feet tall, and is used as a seasoning, especially in drinks.

Parsley (Petroselinum crispum) is best treated as an annual; in its second year, both the leaves and stalks become bitter and by the time the tall yellow flower appears, they're not appealing at all.

Sources:

Carroll Gardens,

444 E. Main St.

Westminster, Md. 21157

410-876-7336

The University of Maryland Home and Garden Information Center, 800-342-2507

"Taylor's Pocket Guide To Herbs and Edible Flowers," Houghton Mifflin Company, 1990

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