Elaeagnus angustifolia Seeds | Russian Olive
LATIN NAME: Elaeagnus angustifolia
COMMON NAME: Russian Olive
Plant Profile
The metallic look of the foliage is not a bloom or a wax. It is produced by dense coats of peltate scales, shield-shaped structures made of radiating cells that sit in the leaf surface like small umbrellas and give the olive family its characteristic sparkle. Look at a leaf with a lens and the surface resolves into overlapping saucers rather than fine hairs. The scales reduce water loss and reflect light, and they are the reason the tree reads as silver from a distance and grey-green up close.
The flowers have no petals at all. What looks like a small yellow trumpet is a calyx tube with four reflexed lobes, and it is the part that carries both the scent and the nectar. The flowers open in late spring on the new wood of the previous season, and their perfume carries a long way on a warm evening.
The fruit looks like a berry and behaves like one, but botanically it is an achene enclosed in a fleshy hypanthium: a single hard stone wrapped in a sweet, mealy covering built from the fused bases of the flower parts. That structure is why the fruit can be eaten out of hand, and why the stone passes through a bird intact.
Russian olive carries a second economy underground. Its roots form nodules with Frankia, a filamentous actinomycete that fixes atmospheric nitrogen inside the plant’s tissue, the same partnership found in alders and sea buckthorn. This is why the tree thrives on spoil, gravel and sand where little else will grow, and why its litter is unusually rich in nitrogen. The consequence for a planting scheme is real: the tree improves the soil it grows in, and it also changes the soil chemistry for everything planted nearby.
Because the roots tolerate metals as well as salt, the species has been trialled for phytoremediation on mine tailings and along polluted roadsides, where it takes up cadmium, lead and zinc into root and shoot and holds the soil against erosion at the same time. It is also studied as a nurse crop for rehabilitating saline land, which is the same set of traits that makes it a problem when it arrives in a river system uninvited.
Science & Biotechnology
The stone holds a seed oil dominated by linoleic acid, the drying-type oil that made the species interesting to paint and varnish research, and the fruit skin carries carotenoid pigments that give the ripe mealy flesh its warm colour. The flowers, leaves and fruit also contain harman-type alkaloids, among them elaeagnine, a class of compound the family shares. Essential oil distilled from the flowers is dominated by the same aromatic alcohols that carry the scent, and it has been examined as a flavouring material.
Uses & Benefits
In its native range the tree is simply a useful one: a windbreak, a hedge, a source of sweet mealy fruit sold in markets from Iran to Kazakhstan, and a nectar plant for bees. In North America it spreads by seed carried in the guts of cedar waxwings and robins, and because the seedlings establish in damp ground it concentrates along rivers, exactly where native willow and cottonwood regenerate. Because its litter raises soil nitrogen, the ground beneath a thicket changes chemically, and the community that follows is a different one. Several states now require landowners to control it.
Growing from Seed
During the shelterbelt campaigns of the 1930s, American soil conservation services planted hundreds of millions of Russian olive along the wind-scoured fields of the Great Plains. The choice looked sensible: the tree tolerates drought, salt, gravel and alkali, and it grows fast enough to break a wind within a few seasons. Eighty years later the same species is listed as a noxious weed in several western states, dense in river bottoms where it displaces the native cottonwoods and willows, and its presence divides land managers more sharply than almost any other plant. The argument is the whole of its story, and it rests on one botanical peculiarity.
Clean the flesh from the stones and sow them in autumn, about two centimetres deep, in a mix of two parts loam, one part coarse grit and a scattering of ground limestone, then leave the pan outdoors through the winter so that cold and damp can soften the coat. Stored seed sown in spring should be given a cold damp spell in the refrigerator first, or many stones will simply sit. Space seedlings twenty centimetres apart in the row and prick them out when the second true leaf has opened, handling the brittle roots gently. The young foliage is silvery from the start.
The tree suckers freely from the roots, so a shelterbelt thickens itself without help, but a garden specimen needs those suckers cut away each winter if a single trunk is wanted. Clip hedges after flowering, and take the top of the row in narrower than the base. Established plants want no feeding at all, and a nitrogen feed only makes soft growth that the wind shreds; where the tree is grown for fruit, a light potash dressing is enough.
Oleaster is prone to canker on injured wood, so prune in dry weather and cut back to clean timber. Scale insects colonise the shaded stems, spider mites build up in hot, dusty sites, and the tree is susceptible to Verticillium wilt, which is one reason it should not follow tomatoes, potatoes or other susceptible crops on the same ground. Where it is grown as fruit, birds will strip the crop as it ripens.
Our Take
Grow Russian olive for a windbreak or a dry bank, and keep it away from a river or a small garden where its suckers will take over. If you want the silvery foliage without the argument, the large-fruited oleaster is a well-behaved relative with better fruit, and the large-leaved oleaster makes a fine evergreen hedge for a milder garden. The Italian alder fixes nitrogen in the same way and suits wetter ground.
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