Fertilising guide
How to fertilise Phlox drummondii 'Intensia Cabernet' (Phlox drummondii 'Intensia Cabernet')— schedule & NPK
Also called Intensia Cabernet Annual Phlox, Cabernet Drummond Phlox.
More about phlox drummondii 'intensia cabernet'
About Phlox drummondii 'Intensia Cabernet'
Phlox drummondii 'Intensia Cabernet' · also called Intensia Cabernet Annual Phlox, Cabernet Drummond Phlox · flowering
'Intensia Cabernet' is a vigorous annual phlox bearing masses of rich wine-red blooms over a tidy mounding habit from spring to frost. More heat- and humidity-tolerant than older phlox, it self-cleans, resists mildew well and flowers without deadheading. Pet-safe and pollinator-friendly, it suits containers, borders and baskets in full sun.
Growth habit: Mounding, well-branched and spreading, forming a dense cushion smothered in flower clusters. Self-cleaning and continuously flowering without deadheading.
Watch for — Reduced flowering: From insufficient sun or excess nitrogen. Site in full sun and use a balanced feed for non-stop bloom.
What fertiliser phlox drummondii 'intensia cabernet' actually wants — and why
Phlox drummondii 'Intensia Cabernet' 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 phlox drummondii 'intensia cabernet': 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 phlox drummondii 'intensia cabernet', 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 phlox drummondii 'intensia cabernet':
Feed every 2-4 weeks with a balanced liquid fertiliser through the growing season, or use slow-release granules at planting. Steady feeding sustains the continuous flush; avoid heavy nitrogen, which favours leaves over blooms. Treat that as every 2-4 weeks 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 phlox drummondii 'intensia cabernet' 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 phlox drummondii 'intensia cabernet'
Half strength is the safe default for phlox drummondii 'intensia cabernet' — 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 phlox drummondii 'intensia cabernet' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the phlox drummondii 'intensia cabernet' watering schedule.
Signs you are over-feeding phlox drummondii 'intensia cabernet'
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for phlox drummondii 'intensia cabernet':
- 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 phlox drummondii 'intensia cabernet'
- 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 phlox drummondii 'intensia cabernet' care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of phlox drummondii 'intensia cabernet' 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 phlox drummondii 'intensia cabernet'
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 phlox drummondii 'intensia cabernet' — frequently asked questions
What fertiliser does phlox drummondii 'intensia cabernet' 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. Phlox drummondii 'Intensia Cabernet' 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 phlox drummondii 'intensia cabernet'?
Feed every 2-4 weeks with a balanced liquid fertiliser through the growing season, or use slow-release granules at planting. Steady feeding sustains the continuous flush; avoid heavy nitrogen, which favours leaves over blooms. Feed every 2-4 weeks with a balanced liquid fertiliser through the growing season, or use slow-release granules at planting. Steady feeding sustains the continuous flush; avoid heavy nitrogen, which favours leaves over blooms. Treat that as every 2-4 weeks 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 phlox drummondii 'intensia cabernet'?
Half strength is the safe default for phlox drummondii 'intensia cabernet' — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding phlox drummondii 'intensia cabernet' 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 phlox drummondii 'intensia cabernet' 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 phlox drummondii 'intensia cabernet'?
Flush the pot of phlox drummondii 'intensia cabernet' 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
- Phlox drummondii 'Intensia Cabernet' care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water phlox drummondii 'intensia cabernet' — 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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