Repotting guide

When & how to repot Purple-Top Germander (Teucrium hircanicum)

Also called Purple-top germander, Caucasian germander, Iranian germander.

More about purple-top germander

About Purple-Top Germander

Teucrium hircanicum · also called Purple-top germander, Caucasian germander · flowering

Teucrium hircanicum is a vigorous, clump-forming herbaceous to semi-evergreen perennial native to the Caucasus region, northern Iran (Hyrcania), and adjacent Turkey, where it grows in open woodland margins, rocky slopes, and disturbed ground. It produces tall, showy spikes of rich burgundy-purple flowers over a very long season from midsummer through autumn, making it one of the most garden-worthy Teucrium species. It is more tolerant of moisture and shade than most Mediterranean relatives, though it still dislikes waterlogging. Treat as mildly toxic to pets in line with the Teucrium genus.

Mature size: 60–90 cm tall and 45–60 cm wide.

How to tell purple-top germander needs repotting

Repotting on a calendar is less reliable than reading the plant. For purple-top germander, 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 purple-top germander) 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 purple-top germander

Only every 2–4 years, when genuinely crowded. Purple-Top Germander 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. Upright, clump-forming herbaceous or semi-evergreen perennial with tall, narrow flower spikes..

What size pot to step purple-top germander up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Purple-Top Germander 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 purple-top germander 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 purple-top germander

Early spring, just as new growth restarts, is the ideal window for purple-top germander. 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 purple-top germander

Confirm it actually needs it. Slide purple-top germander 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 purple-top germander 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 well-drained, moderately fertile, neutral to alkaline, 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 purple-top germander 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 purple-top germander

Purple-Top Germander wants well-drained, moderately fertile, neutral to alkaline. Grows in a wider range of soils than most Teucrium species, including loam and chalk soils; avoid heavy, poorly drained clay, which causes crown rot over winter. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting purple-top germander — frequently asked questions

How often should you repot purple-top germander?

Only every 2–4 years, when genuinely crowded for purple-top germander. Only repot purple-top germander 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 well-drained, moderately fertile, neutral to alkaline. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does purple-top germander need?

When is the best time of year to repot purple-top germander?

Does purple-top germander like to be root-bound?

Yes — purple-top germander 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 purple-top germander after repotting?

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