How to Sow Biennial Plants

Biennial plant species use their first year of life to gather strength and build up nutrient reserves. Only in the second year do they delight us with flowers.

Gardening biennial plants – hollyhocks and foxgloves

Some of these biennial plant species, such as foxglove (Digitalis purpurea) and hollyhock (Alcea rosea), are particularly impressive bloomers.

Foxgloves, with their long, upright inflorescences, make striking accents in the garden and are well suited to the design of a “Woodland Garden”, such as those sometimes presented at the Chelsea Flower Show in London: Gardens with loosely growing trees that exude an almost woodland charm.

With their large flowers, hollyhocks have a very romantic effect and are reminiscent of cottage or country gardens. A small gap in the ground is often enough for the magnificent hollyhocks to gain a foothold on a sunny wall or fence. This is how you sometimes see them along fences or even at house entrances or next to driveways, because even if they only have a small amount of floor space available, they develop into large plants.

Hollyhocks and foxgloves are also ideal for friends of “black box gardening”, because by self-seeding they conquer the space in the garden that suits their location requirements. Dynamics and chance play an important role here. Thus, self-seeding plants can offer new impressions and surprising effects year after year.

Tips for biennial plants – the best way to grow them

In the greenhouse or cold frame they develop into vigorous young plants that soon begin to flower the following year.

Pansies, horned violets, bearded carnations and forget-me-nots planted out in rows in late summer can be transplanted into the border with soil in spring. On the other hand, hollyhocks, foxgloves and bellflowers should be planted in the right place. They do not tolerate transplanting well. Fertilise the young plants occasionally with a liquid flowering plant fertiliser until the end of August and then again from March until they start to flower.

The most beautiful biennial plant species

Species Flowering Sowing

FloweringSowingStock rose (Alcea rosea) VI-XII III-VIII
Lady's bellflower (Campanula media) VI-VII V-VII
Bearded carnation (Dianthus barbatus) VI-VIII VI-VIII
Foxglove (Digitalis purpurea) VI V-VII
Forget-me-not (Myosotis sylvestris) III-V V-VIII
Mullein (Verbascum species) VII-VIII VI-VII
Horned violets (Viola hybrids) IX-XI/III-VI VI-VII
Pansies (Viola wittrockiana) I-VII VI-VI