Repotting guide

When & how to repot Woolly Jerusalem Sage (Phlomis lanata)

Also called Woolly Jerusalem sage, Woolly phlomis.

More about woolly jerusalem sage

About Woolly Jerusalem Sage

Phlomis lanata · also called Woolly Jerusalem sage, Woolly phlomis · flowering

Phlomis lanata is a low, mound-forming, evergreen sub-shrub native to Crete and the Greek islands, where it grows on dry rocky hillsides and garrigue scrub. It is prized for its exceptionally dense, white-woolly leaves and whorls of bright yellow flowers borne in late spring and early summer. Excellent drainage and full sun are non-negotiable — this species is very intolerant of winter wet. Phlomis lanata is not listed on the ASPCA database; it is classified here as mildly-toxic due to insufficient confirmed safety data.

Mature size: 45–60 cm tall and 60–75 cm wide (approximately 18–24 in × 24–30 in).

Watch for — Winter wet / root rot: Wet, cold soils in autumn and winter are the primary killer; plant in raised beds or on slopes with added grit, and avoid overhead irrigation in autumn.

How to tell woolly jerusalem sage needs repotting

Repotting on a calendar is less reliable than reading the plant. For woolly jerusalem sage, watch for these signs:

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for woolly jerusalem sage) flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot woolly jerusalem sage

Only every 2–4 years, when genuinely crowded. Woolly Jerusalem Sage is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Low, compact, dome-shaped evergreen sub-shrub with densely woolly-white stems and leaves..

What size pot to step woolly jerusalem sage up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Woolly Jerusalem Sage positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping woolly jerusalem sage into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot woolly jerusalem sage

Early spring, just as new growth restarts, is the ideal window for woolly jerusalem sage. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting woolly jerusalem sage

Confirm it actually needs it. Slide woolly jerusalem sage out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip woolly jerusalem sage out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh very free-draining, poor sandy or stony soil, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water woolly jerusalem sage again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for woolly jerusalem sage

Woolly Jerusalem Sage wants very free-draining, poor sandy or stony soil. Prefers calcareous or gravelly soils with a neutral to alkaline pH (6.5–8.5); amend heavy clay soils with horticultural grit before planting. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting woolly jerusalem sage — frequently asked questions

How often should you repot woolly jerusalem sage?

Only every 2–4 years, when genuinely crowded for woolly jerusalem sage. Only repot woolly jerusalem sage every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using very free-draining, poor sandy or stony soil. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does woolly jerusalem sage need?

When is the best time of year to repot woolly jerusalem sage?

Does woolly jerusalem sage like to be root-bound?

Yes — woolly jerusalem sage genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise woolly jerusalem sage after repotting?

Not immediately. Wait about 4 weeks after repotting woolly jerusalem sage. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.