Biennial flowers from seed: foxglove, hollyhock and friends
Biennials grow leaves in their first year and flower in their second, then set seed and die. The trick is to sow in late spring or early summer so plants are big enough to overwinter, and to let a few set seed so they self-sow.
Sowing and transplanting
Sow outdoors in a nursery bed or in trays from late spring to midsummer. Prick out, then plant in their flowering positions in autumn. Foxgloves and hollyhocks are the classic examples; sweet william, wallflowers, honesty and forget-me-nots are others.
Overwintering and care
Plants are hardy but benefit from a mulch and good drainage in cold, wet winters. Water in the first summer and feed lightly in spring. Stake tall flower spikes.
Seed saving
Let a few flower spikes ripen and collect the dry capsules. Biennials often self-sow if the seed heads are left in place.
Where they work
Cottage gardens, borders, cutting gardens, shade, wildlife gardens and vertical planting suit tall species; dwarf kinds suit edges, rock gardens and containers.
Plants in this guide
| Plant | Germination temp | Depth | Days | Light | Before sowing |
|---|---|---|---|---|---|
| Foxglove Digitalis purpurea | 65 to 70°F | see page | 10 to 21 | Nothing needed | |
| Hollyhock Alcea rosea | 70 to 70°F | lightly covered | 5 to 21 | Either | Nothing needed |
| Parsley Petroselinum crispum | 65 to 85°F | ¼ in (6 mm) | 14 to 30 | Cover | Nothing needed |
| Carrot Daucus carota | 65 to 85°F | ¼ in (6 mm) | 7 to 21 | Cover | Nothing needed |
| Beet Beta vulgaris | 65 to 85°F | ¾ to 1 in (19 to 25 mm) | 5 to 14 | Cover | Nothing needed |