Fertilising guide
How to fertilise Purple-Top Germander (Teucrium hircanicum)— schedule & NPK
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.
Growth habit: Upright, clump-forming herbaceous or semi-evergreen perennial with tall, narrow flower spikes.
What fertiliser purple-top germander actually wants — and why
Purple-Top Germander is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for purple-top germander: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed purple-top germander, and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For purple-top germander:
Apply a balanced granular fertiliser in spring as growth resumes; an autumn mulch of garden compost improves cold hardiness and feeds the plant as it breaks down. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
The dormant-season rule matters more than the exact interval: skip feeding entirely when purple-top germander is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for purple-top germander
Half strength is the safe default for purple-top germander — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
Feeding always goes onto already-damp soil, never dry roots — water purple-top germander first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the purple-top germander watering schedule.
Signs you are over-feeding purple-top germander
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for purple-top germander:
- Brown, crispy leaf tips and edges with no sign of underwatering.
- A white, crusty salt deposit on the soil surface or pot rim.
- Weak, pale, stretched new growth that flops.
- Lower leaves yellow and drop while the soil is correctly watered.
Signs you are under-feeding purple-top germander
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full purple-top germander care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of purple-top germander with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Organic vs synthetic feeds for purple-top germander
Organic options
A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.
Synthetic / liquid feeds
A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising purple-top germander — frequently asked questions
What fertiliser does purple-top germander need?
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Purple-Top Germander is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
How often should I feed purple-top germander?
Apply a balanced granular fertiliser in spring as growth resumes; an autumn mulch of garden compost improves cold hardiness and feeds the plant as it breaks down. Apply a balanced granular fertiliser in spring as growth resumes; an autumn mulch of garden compost improves cold hardiness and feeds the plant as it breaks down. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
What strength of feed for purple-top germander?
Half strength is the safe default for purple-top germander — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding purple-top germander look like?
Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding purple-top germander year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.
Should I flush the soil of purple-top germander?
Flush the pot of purple-top germander with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Keep reading
- Purple-Top Germander care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water purple-top germander — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
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- All 10153 fertilising guides in the Growli library