Perennial Interest: Jerusalem Sage

Credit: Christine Allen

Wielding shears on the lavender should satisfy your tidying instinct enough to let you spare the dying stems of some taller herbaceous perennials that will play a role in the winter garden if left untouched. Jerusalem sage (Phlomis russeliana) impales its round, brown seed-heads like shish kebabs on sturdy stems that will stand up to winter weather quite nicely. The only disadvantage is the number of seedling plants that have to be extracted from the surrounding area in spring. Somewhat hardier, bronze fennel (Foeniculum vulgare ‘Purpureum’) will grow 1.8 metres tall in a season. Although the umbrella spokes of its seed-heads look fragile, they will withstand a dusting of frost crystals or snow.

Cardoons (Cynara cardunculus) have the tallest, toughest stalks, each bearing aloft the artichoke head that reveals their family relationship to the popular vegetable. Although these heads are full of thistle-like seeds, I find that few of them sprout, even if neglected until they drop to the ground. This is a plant that requires a fair amount of space for its broad, silver leaves in summer; in the centre of a large bed, it makes a striking feature for both summer and early winter. In the Lower Mainland, fresh leaves will emerge from ground level in spring, while in colder regions new plants can be started indoors from saved seed.

Teasel (Dipsacus fullonum) is another staunch survivor that holds a three-pronged candelabra of spiky seed-heads up to winter skies. Its hooked bristles were once used for combing wool, hence its common name. It can grow to 1.8 metres and is another prolific self-seeder.

Ornamental grasses will also give structure to a winter scene, particularly the tall Eulalia grass (Miscanthus sinensis) varieties, which age to pale-blond fountains. Stems should be cut down in spring before the new shoots emerge, and can be used in place of bamboo as garden stakes, although they are not as durable.

The following plants are hardy up to the zone number indicated: Bog rosemary (Andromeda polifolia) – zone 2 • Bronze fennel (Foeniculum vulgare ‘Purpureum’) – zone 6 • Cardoon (Cynara cardunculus) – zone 6 • Corkscew hazel (Corylus avellana ‘Contorta’) – zone 4 • Dragon-claw willow (Salix babylonica ‘Tortuosa’) – zone 4 • English lavender (Lavandula angustifolia) – zone 6 • Eulalia grass (Miscanthus sinensis) – zone 6 • French lavender (Lavandula dentata) – zone 8 • Jerusalem sage (Phlomis russeliana) – zone 7 • Shrubby cinquefoil (Potentilla fruticosa) – zone 2 • Spanish lavender (Lavandula stoechas) – zone 7 • Teasel (Dipsacus fullonum) – zone 4