Fertilising guide
How to fertilise Cosson's Germander (Teucrium cossonii)— schedule & NPK
Also called Cosson's germander, Balearic germander.
More about cosson's germander
About Cosson's Germander
Teucrium cossonii · also called Cosson's germander, Balearic germander · flowering
Teucrium cossonii is a low-growing, prostrate sub-shrub endemic to the Balearic Islands (Majorca and Ibiza), where it scrambles over sun-baked limestone rocks and coastal scrub. It is grown for its dense silver-grey felted foliage and bright cerise to pink-purple flowers produced over a long summer season. The most important care consideration is outstanding drainage and full sun — waterlogged roots in winter cause rapid death, making it best suited to a dry wall top, raised scree bed, or alpine house in wetter climates. Treat as mildly toxic to pets, consistent with the Teucrium genus.
Growth habit: Prostrate to low-spreading, mat-forming evergreen sub-shrub with dense silver felted stems.
What fertiliser cosson's germander actually wants — and why
Cosson's 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 cosson's 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 cosson's 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 cosson's germander:
No regular feeding; a single very light application of slow-release fertiliser in spring is the maximum — rich conditions destroy the silver compact habit and encourage disease. 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 cosson's 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 cosson's germander
Half strength is the safe default for cosson's 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 cosson's germander first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the cosson's germander watering schedule.
Signs you are over-feeding cosson's germander
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for cosson's 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 cosson's 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 cosson's germander care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of cosson's 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 cosson's 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 cosson's germander — frequently asked questions
What fertiliser does cosson's 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. Cosson's 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 cosson's germander?
No regular feeding; a single very light application of slow-release fertiliser in spring is the maximum — rich conditions destroy the silver compact habit and encourage disease. No regular feeding; a single very light application of slow-release fertiliser in spring is the maximum — rich conditions destroy the silver compact habit and encourage disease. 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 cosson's germander?
Half strength is the safe default for cosson's germander — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding cosson's 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 cosson's 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 cosson's germander?
Flush the pot of cosson's 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
- Cosson's Germander care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water cosson's germander — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise clematis 'niobe'
- How to fertilise clematis 'ville de lyon'
- How to fertilise clematis 'ernest markham'
- All 10153 fertilising guides in the Growli library