Fertilising guide

How to fertilise Autumn Olive (Elaeagnus umbellata)— schedule & NPK

Also called autumn olive, autumn elaeagnus, Japanese silverberry.

More about autumn olive

About Autumn Olive

Elaeagnus umbellata · also called autumn olive, autumn elaeagnus · edible

Autumn olive is a vigorous, silvery-leaved deciduous shrub bearing fragrant cream flowers and abundant speckled red, lycopene-rich berries. Nitrogen-fixing and tough on poor soils, it crops heavily in full sun. Note that it is highly invasive across much of North America, so plant only where permitted and where spread can be controlled.

Growth habit: Large, fast-growing, multi-stemmed deciduous shrub with arching, sometimes thorny branches and distinctive silvery-scaled leaf undersides; spreads readily by seed.

What fertiliser autumn olive actually wants — and why

Autumn Olive feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

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 autumn olive: 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 autumn olive, 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 autumn olive:

Essentially none needed. As a nitrogen-fixing shrub it makes its own; feeding is unnecessary and extra nitrogen is wasted and encourages rampant growth. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

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

Follow the crop-feed label rate for autumn olive — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.

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

Signs you are over-feeding autumn olive

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

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen).
Lush foliage hiding the crop; soft growth prone to pests and disease.
Salt crust on the soil and scorched leaf edges in containers.

Signs you are under-feeding autumn olive

Pale, yellowing lower leaves and stunted growth.
Small fruit, poor set, and a quickly exhausted plant.
Blossom-end rot and weak cropping from erratic or insufficient feeding.

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

Flushing and leaching the salts

In containers, fertiliser salts build up fast — water autumn olive thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.

Organic vs synthetic feeds for autumn olive

Organic options

Garden compost or well-rotted manure dug in before planting, plus a liquid comfrey or seaweed feed once fruiting starts. UK: comfrey feed or organic Tomorite; US: Espoma Tomato-tone or Neptune's Harvest. Builds soil and feeds in one.

Synthetic / liquid feeds

A balanced feed at planting then a high-potash tomato feed in fruiting — UK: Growmore at planting then Tomorite (Levington) or Phostrogen; US: a balanced 10-10-10 then Miracle-Gro Tomato or a bloom booster.

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 autumn olive — frequently asked questions

What fertiliser does autumn olive need?

Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen. Autumn Olive feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

How often should I feed autumn olive?

Essentially none needed. As a nitrogen-fixing shrub it makes its own; feeding is unnecessary and extra nitrogen is wasted and encourages rampant growth. Essentially none needed. As a nitrogen-fixing shrub it makes its own; feeding is unnecessary and extra nitrogen is wasted and encourages rampant growth. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

What strength of feed for autumn olive?

What does over-feeding autumn olive look like?

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen). Lush foliage hiding the crop; soft growth prone to pests and disease. Salt crust on the soil and scorched leaf edges in containers. Staying on a high-nitrogen feed once autumn olive starts flowering is the classic error — you get a huge leafy plant and a disappointing crop. Switch to high-potash the moment flowers appear.

Should I flush the soil of autumn olive?