Fertilising guide

How to fertilise Mock Orange (Philadelphus coronarius)— schedule & NPK

Also called mock orange, sweet mock orange.

More about mock orange

About Mock Orange

Philadelphus coronarius · also called mock orange, sweet mock orange · flowering

Philadelphus coronarius is a robust deciduous shrub grown for clusters of single, creamy-white flowers in early summer with a powerful orange-blossom fragrance. Easy and tolerant, it suits mixed borders and informal hedging, flowering on the previous year's wood. Give it full sun to light shade on almost any well-drained soil.

Growth habit: Upright, arching deciduous shrub with a dense, twiggy habit; vigorous and quick to make a sizeable bush, flowering on wood from the previous year.

What fertiliser mock orange actually wants — and why

Mock Orange is a hungry evergreen fruiter with specific needs — a dedicated citrus feed, switched between summer and winter formulas, keeps it cropping and green.

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 mock orange: 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 mock orange, 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 mock orange:

Undemanding. A spring mulch of compost or a single balanced feed is plenty; on fertile soil it may need no feeding at all. Avoid heavy nitrogen, which favours leaf over flower. In practice: a summer citrus feed regularly (often roughly fortnightly) from spring to autumn, switching to a winter citrus feed at a reduced rate over the colder months — citrus feed year-round, unlike most container plants.

The dormant-season rule matters more than the exact interval: skip feeding entirely when mock orange 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 mock orange

Follow the citrus-feed label rate for mock orange and use the correct seasonal formula. The trace-element content matters as much as the NPK — substituting a general feed is the usual cause of yellowing.

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

Signs you are over-feeding mock orange

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for mock orange:

Salt crust on the soil and scorched, browning leaf tips.
Excess soft leafy growth with poor fruit set from too much nitrogen.
Leaf drop shortly after an over-strong feed.

Signs you are under-feeding mock orange

Yellowing leaves — overall pale, or yellow between green veins (magnesium/iron).
Poor flowering and fruit set, small or dropping fruit.
Weak new growth and a generally tired tree.

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

Flushing and leaching the salts

Potted mock orange accumulates salts and benefits from a thorough plain-water flush every couple of months until it drains freely, plus an annual repot or top-dressing of fresh citrus compost.

Organic vs synthetic feeds for mock orange

Organic options

Well-rotted manure or compost mulch plus seaweed and an Epsom-salts (magnesium) drench supports mock orange naturally. UK: organic citrus feed or seaweed + Epsom salts; US: Espoma Citrus-tone or Dr. Earth Citrus.

Synthetic / liquid feeds

A proprietary summer and winter citrus feed — UK: Westland or Vitax Citrus (summer/winter); US: Miracle-Gro or Espoma Citrus. Using the right seasonal formula is the key to keeping mock orange green and cropping.

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 mock orange — frequently asked questions

What fertiliser does mock orange need?

A specialist citrus fertiliser, which carries the higher nitrogen plus the magnesium, iron and trace elements citrus need — generic feeds quickly leave it yellow and chlorotic. Many ranges have a summer (higher-N) and a winter (lower-N) formula. Mock Orange is a hungry evergreen fruiter with specific needs — a dedicated citrus feed, switched between summer and winter formulas, keeps it cropping and green.

How often should I feed mock orange?

Undemanding. A spring mulch of compost or a single balanced feed is plenty; on fertile soil it may need no feeding at all. Avoid heavy nitrogen, which favours leaf over flower. Undemanding. A spring mulch of compost or a single balanced feed is plenty; on fertile soil it may need no feeding at all. Avoid heavy nitrogen, which favours leaf over flower. In practice: a summer citrus feed regularly (often roughly fortnightly) from spring to autumn, switching to a winter citrus feed at a reduced rate over the colder months — citrus feed year-round, unlike most container plants.

What strength of feed for mock orange?

What does over-feeding mock orange look like?

Salt crust on the soil and scorched, browning leaf tips. Excess soft leafy growth with poor fruit set from too much nitrogen. Leaf drop shortly after an over-strong feed. Feeding mock orange an ordinary plant food instead of a citrus-specific one is the defining mistake — it lacks the magnesium and iron citrus demand, and the leaves yellow between the veins no matter how often you feed.

Should I flush the soil of mock orange?