Autumn olive: tough wild fruit with silver-speckled berries

In October, when most berry bushes were picked clean weeks ago, the autumn olive is still full. The branches bend under hundreds of small red fruits, and each one looks as if someone had dusted it with silver. In German it is called Korallen-Ölweide, coral oleaster, and in English autumn olive.

Apart from its silvery leaves it has nothing to do with the olive. Its closest relative in the garden is sea buckthorn, which shares the oleaster family (Elaeagnaceae). And like sea buckthorn, it is a shrub for gardeners who want to do little work and harvest a lot. It does not have its own entry in our plant database yet, so this article is its profile.

A shrub that feeds itself

The special thing about autumn olive sits below ground. Small nodules form on its roots, home to bacteria of the genus Frankia. They take nitrogen from the air in the soil and pass it on to the plant. You know the same principle from peas and beans, and from sea buckthorn.

For you this means autumn olive grows on sandy, stony or exhausted soil where currants would struggle. It does not need nitrogen fertiliser; that does more harm than good, because it pushes out the nodules and only drives leaf growth. In forest gardens and mixed hedges it is often planted as a neighbour for hungrier fruit trees. The leaves it drops in autumn carry the nitrogen into the surrounding soil.

Site and planting

Autumn olive wants sun. It grows in partial shade too, but bears noticeably less there. The soil can be dry, sandy and poor; it only dislikes permanently wet roots. It copes with wind, road salt and heat, and in winter it survives frosts below minus 25 °C.

Give it enough room: a mature shrub grows three to five metres tall and about as wide. For an informal hedge, space the plants two to three metres apart. Plant in autumn, early October to mid-November · CW 40 to 46, or in early spring.

1. Plant two shrubs

   Many autumn olives crop on their own, but with a second shrub of another variety nearby the fruit set rises clearly. Insects pollinate the flowers, so ten to twenty metres between them is fine.

2. No fertiliser in the planting hole

   Dig the hole twice as wide as the pot, loosen the bottom and backfill with the soil you dug out. You need neither compost nor fertiliser.

3. Water in the first year

   Until the shrub is rooted in, water deeply once a week in dry spells. From the second year it looks after itself.

4. Patience until the first harvest

   Plants from cuttings or grafts bear after two to three years, seedlings after four to five.

The fruit: sweet, tart, slightly astringent

The berries are six to nine millimetres across, round to slightly oval and speckled with fine silvery scales. They ripen from mid-September, and here is the most important harvest tip: wait. Half-ripe fruit is strongly astringent and puckers your mouth like an unripe sloe. Fully ripe it turns soft and dark red, with a sweet-tart taste and a touch of astringency, somewhere between redcurrant and a ripe rosehip.

Inside sits a single elongated seed. It is soft enough to eat along with the fruit when you snack straight from the bush. For purée and juice, press the cooked fruit through a sieve and the seeds stay behind.

Besides the red wild forms there are varieties with larger or milder fruit, including yellow-fruited ones such as Autumn olive ‘Amber’ or Autumn olive ‘Fortunella’. If snacking is your main goal, a selected variety serves you better than a seedling whose flavour stays a surprise.

Lycopene: more than in a tomato

The red colour of the berries comes largely from lycopene, the same pigment that makes a tomato red. Research by the US Department of Agriculture found several times the lycopene content of fresh tomatoes in autumn olive. How much exactly varies a lot with plant, variety and ripeness.

Lycopene is fat-soluble, and your body takes it up better once it is heated. A cooked purée eaten with quark, yoghurt or a cheese board makes better use of the pigment than the raw berry. Autumn olive is still no miracle cure, simply a wild fruit that is very rich in pigment.

Harvesting and using the fruit

A mature shrub can carry ten kilograms or more, and picking the berries one by one gets tedious. Here is an easier way: spread an old sheet or a tarp under the shrub and shake the branches firmly. Fully ripe berries drop, half-ripe ones stay put. That way you only harvest the sweet ones. Repeat every few days over three to four weeks.

The berries are soft and split easily. Process them the same day or freeze them.

More ideas for preserving are in Preserving your berry harvest.

Pruning: little, and from the base

Autumn olive needs hardly any pruning. Let it grow freely for the first few years. After that, thin it every two to three years in late winter, mid-February to late March · CW 7 to 13, or right after harvest: take out one or two of the oldest stems at ground level and remove branches that cross or grow into paths.

It also tolerates hard pruning and regrows willingly. Wear sturdy gloves, since many plants carry sharp thorns on their short shoots.

Invasive? An honest look

Autumn olive has a second reputation, and it belongs in this article. In the USA it was planted widely from the 1950s onward as a windbreak and to restore former mining land. Birds ate the berries and spread the seeds, and today it counts as one of the most problematic introduced woody plants in the eastern USA. It overgrows open meadows, and its nitrogen changes poor sites that native plants depend on.

In Central Europe it is not on the EU list of invasive species so far and only escapes here and there. That may change with warmer winters. You can still grow it in the garden with a clear conscience if you keep three things in mind.

If you want to stick to native species, sea buckthorn, cornelian cherry or rosehips give you similarly tough wild fruit.

The relatives: three other oleasters

Several species are sold under the name oleaster, and not all of them carry equally good fruit.

• Goumi (Elaeagnus multiflora): ripens as early as June and July, with larger, elongated fruit on long stalks. It stays smaller at two to three metres.
• Russian olive (Elaeagnus angustifolia): a small tree with strikingly silver leaves. Its fruit is mealy and dry, and it is mainly planted as an ornamental.
• Evergreen oleaster (Elaeagnus × ebbingei): an evergreen hybrid that flowers fragrantly in October and November. Its small, elongated fruits ripen in April and May and are edible, one of the first fruits of the garden year.

The evergreen oleaster is the choice if you want a dense hedge that takes clipping well and stays green through winter. It grows more slowly than autumn olive, can be kept at one and a half to two metres and gives you a small spring harvest as a bonus.

How to combine several fruiting shrubs into a mixed, edible hedge is shown in Planting an edible berry hedge. Autumn olive fits well in the back row there, next to serviceberry and aronia.

Set up a recurring task for mid-September in the Gartenkern diary. Over the years you will see when your shrub was really ripe, and you will not miss the window before the blackbirds find it.

Frequently asked questions

Are autumn olive berries edible?

Yes. The red, silver-speckled berries are edible raw and cooked. Fully ripe they taste sweet and tart with a slight astringency. Unripe fruit is strongly astringent, so wait until the berries are soft and dark red.

When are autumn olive berries ripe?

From mid-September to late October. Ripe berries are soft, dark red and drop when you shake the shrub. If you wait a little longer, the fruit gets sweeter.

Does autumn olive need a pollinator?

Many plants crop on their own, but a second plant of another variety nearby raises the yield clearly. Bees and bumblebees pollinate the flowers.

Is autumn olive invasive?

In North America yes, where birds have spread it into open countryside. In Central Europe it is not on the EU list of invasive species and only escapes here and there. Plant it in the garden rather than on woodland edges or near nature reserves, harvest thoroughly and remove seedlings.

How big does autumn olive get?

Three to five metres tall and about as wide. It grows as a loose, multi-stemmed shrub and is easy to keep in shape by thinning from the base.

What is the difference between autumn olive and goumi?

Goumi (Elaeagnus multiflora) ripens as early as June and July and carries larger, elongated fruit on long stalks. Autumn olive (Elaeagnus umbellata) ripens in September and October with small, round berries and grows considerably larger.