Fertilising guide
How to fertilise Spiny Germander (Teucrium subspinosum)— schedule & NPK
Also called Spiny Germander, Balearic Germander.
More about spiny germander
About Spiny Germander
Teucrium subspinosum · also called Spiny Germander, Balearic Germander · flowering
Teucrium subspinosum is a cushion-forming, spiny, evergreen shrublet endemic to the Balearic Islands (primarily Mallorca and Cabrera), where it grows on dry, stony limestone hillsides. Its twisted, white-woolly, spine-tipped stems bear small grey-green leaves and loose racemes of two-lipped, clear pink flowers in summer. It is one of the most ornamental compact germanders for rock gardens and scree beds, and demands full sun with near-perfect drainage. The plant is mildly toxic if ingested due to diterpene compounds typical of the genus.
Growth habit: Compact, cushion-forming, spiny evergreen shrublet with intricately branched, white-woolly stems.
What fertiliser spiny germander actually wants — and why
Spiny 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 spiny 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 spiny 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 spiny germander:
Feed very lightly with a balanced, low-nitrogen fertiliser in spring only; rich feeding destroys the compact, spiny character and promotes soft, vulnerable growth. 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 spiny 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 spiny germander
Half strength is the safe default for spiny 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 spiny germander first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the spiny germander watering schedule.
Signs you are over-feeding spiny germander
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for spiny 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 spiny 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 spiny germander care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of spiny 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 spiny 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 spiny germander — frequently asked questions
What fertiliser does spiny 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. Spiny 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 spiny germander?
Feed very lightly with a balanced, low-nitrogen fertiliser in spring only; rich feeding destroys the compact, spiny character and promotes soft, vulnerable growth. Feed very lightly with a balanced, low-nitrogen fertiliser in spring only; rich feeding destroys the compact, spiny character and promotes soft, vulnerable growth. 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 spiny germander?
Half strength is the safe default for spiny germander — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding spiny 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 spiny 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 spiny germander?
Flush the pot of spiny 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
- Spiny Germander care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water spiny 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 european ash
- How to fertilise golden ash
- How to fertilise manna ash
- All 10153 fertilising guides in the Growli library