Biennials complete their life cycle in two growing seasons. In the first year they produce only roots, stems and leaves. In their second year they flower and form seeds, then die. (Annuals, meanwhile, germinate, grow, bloom, set seed and die within one year.)
Hardy biennials can be sown outside from late spring to early summer. An exception is forget-me-not (Myosotis), which grows very quickly and shouldn’t be sown until midsummer. If the plants set any flower buds in their first year, pinch the buds off because allowing them to flower will diminish their second-year bloom.
Many biennials reseed themselves, so once you grow a few plants you can end up with a plants every year. In fact, some biennials are commonly thought to be perennials since they appear every year.
You can end up with blooms from biennials every year if you stagger your own new plantings with the existing plants’ self-sowing. For instance if you plant seeds the first year, they will grow and then bloom and sow their seeds the second year. In the third year as those seeds are sprouting, plant second-year transplants, which will bloom that year and set seed, which will sprout in year four when year one’s self-sown seedlings are blooming. From there forward you should have some second-year plants in bloom every year.
- California poppy (Eschscholozia)
- Forget-me-not (Myosotis)
- Foxglove (Digitalis)
- Hollyhock (Alcea)
- Honesty (Lunaria)
- Poppy (Papaver)
- Stock (Matthiola incana)
- Sweet William (Dianthus barbatus)