Russian Olive

The silvery, thorny shelterbelt tree the government once handed out by the thousand - now a listed noxious weed in Colorado and New Mexico that has replaced cottonwood and willow along western rivers. Edible fruit, and still never plant it.

How to recognize it and why never to plant it: a crooked small tree with narrow willow-like leaves silvery on both sides, stout two-inch thorns, intensely fragrant June flowers, and dry mealy silver-tan fruit - fixing nitrogen and seeding every river below it.

You should never plant Russian olive — recognizing it, and telling it from its relatives, is what matters. It is a small, often crooked tree to about 25 feet (sometimes a large shrub), with shaggy, shredding brown bark and silvery twigs. Its leaves are narrow and lance-shaped, willow-like, and silvery-scaled on BOTH surfaces, so the whole crown reads gray from a distance. Branches carry stout thorns up to two inches long. In June it is smothered in small silvery-yellow bell flowers with a heavy sweet fragrance you notice long before you see the tree, and by late summer it carries dry, mealy, silver-tan fruits, each with one hard striped stone.

The comparison people need is with autumn olive (E. umbellata), the invasive of the East and Midwest: autumn olive is a multi-stemmed shrub with oval leaves that are green above and silver only beneath, and its fruit is soft, juicy, and red flecked with silver. Narrow silver-on-both-sides leaves and dry tan fruit mean Russian olive; oval green-over-silver leaves and red berries mean autumn olive. (A third, E. pungens, thorny olive, is the evergreen one in the Southeast.) Russian olive's biology is what makes it a landscape problem: it is a nitrogen fixer, so it establishes on lean, raw, and salty ground where natives struggle and then enriches it; it tolerates drought, flooding, alkalinity, and salinity; it is hardy to about forty below; and it resprouts hard from a cut stump. Tough enough for the Plains is exactly what makes it unstoppable along a river.

How it spreads: heavy crops of bird- and mammal-dispersed fruit that germinate readily on wet, bare, even salty river silt, plus vigorous sprouting from cut stumps and root crowns and rooting from buried branches.

Russian olive spreads mainly by seed. A mature tree sets thousands of stony fruits; birds, deer, raccoons, and livestock eat them through fall and winter and pass the seed intact, which is how new trees appear along fence lines, under perch trees, and miles down a river system from any planting. Water does the rest: fruit and seed float and travel on irrigation ditches and spring floods, then germinate on the wet, bare silt that flooding leaves behind — the same nursery bed that cottonwood and willow seedlings depend on, except Russian olive can also handle the salty, alkaline patches they cannot.

It also holds ground vegetatively. Cut or damaged trees sprout vigorously from the stump and root crown, so a plain cut turns one trunk into a thorny multi-stemmed clump, and low branches buried by silt or soil can root where they lie. Once a stand closes in, it shades out cottonwood and willow seedlings and holds the site indefinitely, which is why removing the trees is only half the job: unless native cover is re-established, the seed rain from upstream simply refills the gap. Control that works therefore combines killing the roots, removing fruiting trees over a whole reach rather than one property, and revegetating with natives.

Control and replacement, not care: pull seedlings, cut-stump or basal-bark treat anything larger in the dormant season (it resprouts), use an aquatic-labelled product with a permit near ditches and rivers, follow up for years, and replant natives.

Scale the method. Seedlings and small saplings pull or dig out of moist soil — take the root crown, and wear thick gloves. Anything larger resprouts hard when merely cut, so the roots have to be killed: cut low and treat the fresh stump surface within minutes, or use a basal-bark application on stems under about six inches, generally in the dormant season from late fall through winter, when the plants are quiet and the thorns are visible. On big riparian projects, machines pull or mulch the stems and crews follow with treatment of the sprouts; either way the follow-up matters more than the first pass. Whatever you use, it must be a product whose label lists the site you are treating, and you must follow that label — rates, protective equipment, buffers, and grazing intervals are legally binding.

Water changes the rules, and this tree lives at the water. Treating plants standing in or over a ditch, canal, creek, river, or wet meadow requires a product specifically labelled for aquatic sites, and that work commonly requires a permit and often a licensed applicator — on irrigation systems you may also need to clear it with the ditch company or irrigation district, since treated water goes on somebody's crop downstream. Ask your county weed office, extension service, or state department of agriculture before you start; many counties will help, and some cost-share the work because Russian olive is a listed weed.

Sequence it: take out fruiting trees first, work with your neighbors along the same reach if you can, and plan on three to five years of follow-up on sprouts and seedlings. Then put natives back, or the ground simply refills: silver buffaloberry is the closest match — a native, silvery, thorny, nitrogen-fixing, berry-bearing windbreak shrub — alongside golden currant, chokecherry, American plum, skunkbush sumac, hackberry, or Rocky Mountain juniper. On a river bank, cottonwood and native willows are the point of the whole exercise.

Honestly, the dry mealy fruits are edible and are a traditional food across Central Asia and Iran - but that is no reason to plant it. Ecologically it is a net loss: it displaces cottonwood and willow and enriches river soils in ways that favor more weeds.

Russian olive carries the same honest paradox as autumn olive and kudzu: it is genuinely edible and it must not be planted. The fruit is dry, mealy, and sweet-tart, more like a date than an olive, with one hard striped stone; in Iran and across Central Asia it is a real food, dried and eaten as senjed, ground into flour, and included among the seven symbolic items of the Persian new-year table. In the US it makes a decent jelly and a passable dried snack, and it is fine to use fruit from a tree you are cutting down. Skip roadside, ditch-bank, and right-of-way trees, which are sprayed on a schedule, and never plant a seed or move a rooted sucker.

None of that offsets what it does to a river. Western riparian corridors are narrow ribbons of habitat in dry country, and they are built on cottonwood and willow, which feed native insects, hold banks, and shade water. Russian olive replaces them with a thorny thicket that supports far fewer native insects and a poorer bird community, holds banks differently, and can dry and change how a channel behaves. As a nitrogen fixer it also enriches soils that were naturally lean, which tends to favor other weedy species rather than the natives adapted to them — so its effect outlasts the individual tree. Its own fruit does feed birds through winter, which is exactly the mechanism of its spread rather than a redeeming feature. The right relationship is removal, with a bucket of fruit as a consolation prize.

Introduced in the 1800s and distributed by the thousand for Dust Bowl shelterbelts, erosion control and wildlife plantings, Russian olive was recommended by the same agencies that now list it as a noxious weed.

Russian olive reached North America in the 1800s as an ornamental, and came into its own in the twentieth century as an answer to hard country. After the Dust Bowl, federal and state programs planted enormous numbers of trees for shelterbelts and windbreaks across the Plains, and Russian olive was close to ideal on paper: it survived drought, wind, cold to forty below, alkaline and salty soils, and neglect; it fixed its own nitrogen; it grew fast; and it fed wildlife. Conservation districts and extension services handed out seedlings by the thousand for windbreaks, erosion control, mine reclamation, and wildlife plantings well into the second half of the century.

Then the birds moved it off the farm. By the 1980s and 1990s, land managers across the interior West were watching river corridors turn from cottonwood galleries into Russian olive thickets, and the same agencies that had distributed it began listing it as a weed. Today it is a List B noxious weed in Colorado and a Class C noxious weed in New Mexico, listed or restricted in other western and northeastern states, and the subject of large, expensive riparian restoration programs. It is one of the clearest cautionary tales in this catalog: a plant recommended by responsible people, for good reasons, in a landscape that needed help — and a reminder that tough enough to survive anything is exactly the trait that becomes uncontrollable once a bird gets involved.

Confirm it against autumn olive (narrow silver-on-both-sides leaves, dry tan fruit, thorns), never just cut it, treat stumps on-label in the dormant season, get a permit and an aquatic product near ditches and rivers, and replant natives.

Is this Russian olive or autumn olive? Russian olive is a tree with narrow, willow-like leaves silvery on both sides, stout two-inch thorns, and dry, mealy, silver-tan fruit. Autumn olive is a shrub with oval leaves green above and silver beneath, and soft red berries flecked with silver. Is it legal to have? It is a listed noxious weed in Colorado (List B) and New Mexico (Class C) and restricted elsewhere; a listing can carry a duty to manage it, not just a ban on selling it, so check your state and county rules. I cut it down and it came back as a thorn bush. Expected — it sprouts from the stump and root crown. Cut low and treat the fresh cut face immediately, or basal-bark small stems in the dormant season, always on-label. It is growing in my irrigation ditch. That is aquatic work: use an aquatic-labelled product, expect to need a permit or a licensed applicator, and clear it with your ditch company or irrigation district first — treated water goes downstream onto someone's field. Can I eat the fruit? Yes; it is dry and mealy, better dried, and a traditional food in Central Asia and Iran. Avoid roadside and ditch-bank trees, which are sprayed, and do not let edibility become a reason to keep the tree. Why do the thorns hurt so much? They are stiff and deep-puncturing, and punctures infect easily — wear thick gloves, boots, and eye protection, and clean any deep puncture properly. What should I plant for a windbreak instead? Silver buffaloberry, golden currant, chokecherry, American plum, skunkbush sumac, hackberry, or Rocky Mountain juniper.

Extraordinarily tough - hardy to roughly zone 2 and drought-, salt- and alkali-tolerant - so its limits are set by water and disturbance rather than climate: worst along western rivers, ditches and shelterbelts from the Plains through the Great Basin.

Russian olive is about as climate-proof as an introduced tree gets in North America: hardy to roughly zone 2, tolerant of drought once established, and comfortable on alkaline and saline soils that defeat most trees. That is precisely why it was planted from the Dakotas to New Mexico. Its invasion is heaviest through the Great Plains, the Rocky Mountain states, the Great Basin, and the interior Southwest — Colorado, New Mexico, Utah, Wyoming, Montana, Idaho, Nevada, and the Dakotas — with populations in the Pacific Northwest interior and a spreading foothold in the Northeast.

What actually governs it is water and disturbance, not temperature. It needs a wet germination bed, so it concentrates along rivers, irrigation ditches, canals, reservoir margins, and wet meadows, and it exploits the bare silt left by floods, grading, and grazing. Anything that alters a river's natural flooding — dams, diversions, channel work — tends to favor it over cottonwood and willow, which need specific flood timing to regenerate; the more managed the river, the more Russian olive. Hotter, drier conditions and heavier salt loads in irrigated valleys widen that advantage further. Wherever you are in its range the advice is the same: never plant it, learn the silver-both-sides leaves and the dry tan fruit, take out fruiting trees first, treat the roots rather than merely cutting, and get the right product and permits before you touch anything standing in water.