Phlomis russeliana: Growing the Evergreen Jerusalem Sage

By The Diggers Club - Australia's No.1 Gardening Club | Published: 2026-11-04

Category: Consigli e cura

Plant Phlomis russeliana in full sun and well-drained soil, water it through its first summer, then cut back old stems in spring. Here's the full care sequence.

Quick answer

Give Phlomis russeliana full sun and sharply drained soil, water it through its first summer, then leave the flower stems standing for winter structure and cut them back in early spring. Divide crowded clumps every few years to keep the ground cover dense.

Why drainage matters more than watering

Phlomis russeliana is listed as thriving in full sun and well-drained soils, and that combination is the line between a long-lived plant and a short one. In heavy clay or a low spot that holds winter rain, the crown can rot before the plant ever gets going. If your only sunny spot is clay, plant on a raised mound of coarse grit and compost rather than digging a deeper hole.

Once established, the plant's drought tolerance does the work for you. The trade-off is that it resents being fussed over: extra summer watering in ordinary garden soil encourages soft growth and fewer of the hooded yellow flowers.

Coastal gardens and mass planting

The catalog describes this as a superb perennial for coastal gardens, which suits a plant that tolerates wind and lean, sandy ground better than rich, sheltered beds. It also notes that planting en masse creates good ground cover, so space plants closer than you would for a specimen clump and let them knit together.

If you garden in a humid subtropical summer, expect the foliage to look tired after heavy rain; that is a climate limitation rather than a care failure, and cutting back in spring resets the clump.

Step-by-step: planting, pruning and dividing

Choose the position: Pick the sunniest spot you have with free-draining soil, and avoid hollows where water pools after rain. On clay, plant into a raised mound of grit and compost. If the spot stays wet for a day after rain, it is the wrong spot.
Plant at the right depth and spacing: Set the crown at soil level, not buried, and space plants closer together if you want the massed ground cover the catalog describes. A buried crown is the most common reason a new plant sulks.
Water through the first summer only: Water deeply at planting and keep the soil moist through the first summer while roots establish, then ease off. After that, rely on rainfall and water only in severe drought. Stop routine watering once new growth appears in spring.
Leave the stems for winter structure: Do not cut the flower stems down in autumn. The catalog notes they provide good winter structure, and seed heads feed birds and catch frost. Cut back in early spring, not autumn, unless the clump looks messy.
Prune in early spring: Cut the old stems to the base as new basal growth starts. Remove any dead or damaged leaves at the same time. Pruning too early in winter removes the structure you planted it for.
Divide crowded clumps: Lift and divide every three to four years in early spring, replanting the vigorous outer pieces and discarding the woody centre. Divide before the centre goes bare, not after.

Product facts

Phlomis russeliana: Phlomis russeliana bears whorls of hooded yellow flowers from late spring to early autumn and holds an RHS Award of Garden Merit. A long flowering window means one planting earns its space for months, and the award signals a plant that has been assessed for garden performance.
Phlomis russeliana