Most popular flowers fall into two categories: annuals, which you plant anew each season, and perennials, which you plant once and they rebloom every year. But a few old-fashioned favorites, such as hollyhock, foxglove, and sweet William, are biennials, which grow leaves one year and flower the next. They reward your patience with spectacular blooms rarely available in nurseries. And most self-sow reliably, meaning you plant them once and the work is done!
A biennial spends its first season producing a rosette of leaves. Below ground is a fleshy taproot—the storage depot for starches and sugars. In winter, the plant goes dormant. Come spring, it wakes up with a big burst of energy and produces a tall beauty of a flower stalk followed by a full load of seeds, ensuring survival—of the species, that is. The original plant expires from the effort.
Fortunately (or unfortunately, in the case of weeds), hardy biennials are champion self-sowers. So even though the parent plant turns brittle and dies, there are offspring to take its place. And you can easily move these young plants in their first year anywhere you want them.
1. Learn to recognize the first-year foliage so you don't inadvertently pull it out.
2. Give young plants a boost by thinning them as needed and mulching with compost.
3. Transplant only in the first year of growth, not the second.
So that you're never without biennials' graceful beauty, follow the advice of Roberta McQuaid, staff horticulturist at Old Sturbridge Village, in Massachusetts: Plant the seeds of biennials for two consecutive years. That way you'll always have plants coming into bloom. If your growing season is sufficiently long, seedlings may even appear that same year—to then bloom after the winter dormancy.
Hardy biennials like hollyhocks are the stars of the coveted cottage garden, where their spires rise above poppies, larkspurs, and daisies.