Fertilising guide

How to fertilise Clematis 'Multi Blue' (Clematis 'Multi Blue')— schedule & NPK

Also called Multi Blue clematis, double blue clematis.

More about clematis 'multi blue'

About Clematis 'Multi Blue'

Clematis 'Multi Blue' · also called Multi Blue clematis, double blue clematis · flowering

Clematis 'Multi Blue' is a distinctive double-flowered deciduous climber producing deep violet-blue blooms with a spiky pompon centre of narrow inner tepals. A sport of 'The President', it flowers on old wood in early summer and again on new growth later, suiting trellises, fences and large patio pots.

Growth habit: Deciduous twining climber clinging by leaf petioles; double flowers on old wood early, with later, often semi-double blooms on new growth.

What fertiliser clematis 'multi blue' actually wants — and why

Clematis 'Multi Blue' is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.

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 clematis 'multi blue': 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 clematis 'multi blue', 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 clematis 'multi blue':

Feed in spring with a balanced or high-potash fertiliser and repeat every 4-6 weeks until late summer to support both flowering flushes. Mulch with rotted manure annually and top up container compost each spring. For a hungry bloomer that means feeding regularly — every 4-6 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

The dormant-season rule matters more than the exact interval: skip feeding entirely when clematis 'multi blue' 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 clematis 'multi blue'

Follow the flowering-feed label rate for clematis 'multi blue', or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.

Feeding always goes onto already-damp soil, never dry roots — water clematis 'multi blue' first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the clematis 'multi blue' watering schedule.

Signs you are over-feeding clematis 'multi blue'

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for clematis 'multi blue':

Lots of lush leaves but few flowers (too much nitrogen).
Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
Soft, sappy growth prone to aphids and mildew.

Signs you are under-feeding clematis 'multi blue'

Sparse, small, short-lived flowers and pale foliage.
A tired plant that stops blooming early in the season.
Weak growth and poor repeat-flowering after the first flush.

If the symptoms point at watering, light or roots rather than nutrition, the full clematis 'multi blue' care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Container-grown clematis 'multi blue' accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.

Organic vs synthetic feeds for clematis 'multi blue'

Organic options

A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.

Synthetic / liquid feeds

A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.

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 clematis 'multi blue' — frequently asked questions

What fertiliser does clematis 'multi blue' need?

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Clematis 'Multi Blue' is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

How often should I feed clematis 'multi blue'?

Feed in spring with a balanced or high-potash fertiliser and repeat every 4-6 weeks until late summer to support both flowering flushes. Mulch with rotted manure annually and top up container compost each spring. Feed in spring with a balanced or high-potash fertiliser and repeat every 4-6 weeks until late summer to support both flowering flushes. Mulch with rotted manure annually and top up container compost each spring. For a hungry bloomer that means feeding regularly — every 4-6 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

What strength of feed for clematis 'multi blue'?

What does over-feeding clematis 'multi blue' look like?

Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on clematis 'multi blue' is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.

Should I flush the soil of clematis 'multi blue'?