Adventive Wild Plants in Israel

Israel's flora is divided into seven broadly recognized groups, one of which consists of species from the Americas, Australia, and South Africa that have begun growing in the country without human assistance.[5] These plants form one part of a broader non-native spectrum. Alien plants may remain confined to cultivation or occur outside it at casual, naturalized, or invasive stages, depending on their capacity to persist and spread.[1][2]

Human activity has reshaped Israel's vegetation over millennia through the collection and cultivation of plants, land clearance, the domestication of grazing animals, and repeated introductions of new species.[5]

Hundreds of plant species, including many originating in the New World, were brought into the land, together with ornamental plants sourced from countries around the world.[6] Hundreds of weed species also became associated with cultivated areas; some were established from antiquity, while others arrived more recently with introduced crops and other plants.[6] A 2009 survey identified ornamental garden plants and trees formerly used for forestry or soil stabilization as principal sources of invasive plants entering Israel's natural areas.[1]

Scientific literature on Israel's flora applies a tiered classification system to non-native plants. An "alien" plant is one that does not belong to Israel's indigenous flora; alien status by itself carries no implication of ecological harm.[1]

A "casual" alien is able to flower, and sometimes reproduce, outside the area where it is cultivated, but cannot establish a self-renewing population over time; without repeated introductions of new individuals, the population cannot survive.[1] A "naturalized" alien, by contrast, forms self-replacing populations without human intervention for at least ten years.[2] An "invasive" plant meets the naturalized threshold and also demonstrates substantial reproduction and spread away from parent plants.[2] These definitions matter when interpreting published statistics because figures for invasive, naturalized, casual, and adventive plants reflect different criteria.

The 1999 bilingual checklist Checklist and Ecological Data-Base of the Flora of Israel and Its Surroundings, credited to Ori Fragman and collaborators, covers Israel, Jordan, the Palestinian Autonomy, the Golan Heights, Mount Hermon, and Sinai, and provides wild-plant names in Latin.[7] The catalog records it as 69 and 107 pages, with maps.

Jean-Marc Dufour-Dror's Alien Invasive Plants in Israel, published in Jerusalem in 2012 with the involvement of Israeli environmental and nature-conservation bodies, addresses the subset of non-native plants that have become invasive.[9] A separate Hebrew-language volume, הצמחים הפולשים בישראל (Invasive Plants in Israel), appeared in a first edition in 2010 and an expanded and updated second edition in 2019, with scientific editors including Hagar Leschner, Margareta Walczak, Ori Fragman-Sapir, and Tuvia Yakobi; its bibliography spans pages 214–246.[10]

A 2009 survey conducted jointly by the Israel Nature and Parks Authority and the Jerusalem Institute for Israel Studies covered 83 sites, including protected areas and ecologically important unprotected open areas, during 2006–2007.[1] It recorded 45 alien plant species in total: 32 classified as invasive, nine as naturalized, and four as casual.[1]

The 2006–2007 survey's species table identified four alien plants as casual—the smallest category in the report, representing roughly 9% of all alien species recorded.[1] These were Myriophyllum aquaticum (אלף-העלה אקווטי; a perennial aquatic plant), Cyperus imbricatus (גומא, with the report noting that a Hebrew name had not yet been established; a perennial herb), Pistia stratiotes (חסת המים; a perennial floating aquatic plant), and Acacia sclerosperma subsp. sclerosperma (שיטה מחטנית; a tree).[1]

Site-level records place Myriophyllum aquaticum at Ein Naburiya in Birya Forest and Acacia sclerosperma subsp. sclerosperma east of the northern part of Lahav Nature Reserve.[1] These are individual survey locations, not evidence that either plant was widespread across Israel at the time. Because the report assigned invasion stage at the national scale—with the understanding that a species could be at different stages in different locations—the four-species casual list reflects the survey's methodology and timeframe and should not be read as a timeless national inventory.[1]

Broader surveys have produced larger counts. Israel's 2016 national biodiversity report cited a study identifying 166 invasive alien plant species in the country, of which 59 were common or very common.[8] Fifty-nine species were found in protected areas, where 28 were common.[8] A 2025 report distinguished 174 alien plant species known to enter natural areas from the 61 classified as invasive and estimated that seven alien plant species were added during 2018–2023 and remained at early stages of spread.[11]

The national biodiversity report notes that Israel's natural areas have been reduced and fragmented by development and that disturbed habitats associated with infrastructure—including denser road networks—can function as corridors for invasive plants.[8] Israel's government list of unwanted alien ornamental plants is a voluntary prevention tool covering 141 alien ornamental taxa: 17 were classified as casual, eight as naturalized, and 23 as invasive, while 45 had not been observed in Israel and 48 remained confined to planted sites.[2]

Ambrosia confertiflora, a perennial herb originating in the south and southwest United States, is identified in Israel's national biodiversity report as the country's most harmful invasive plant species.[8] Agricultural seed mixtures are its usual vector of spread, though seeds have sometimes arrived via birds; a national control plan was published in 2014.[8]

The Hottentot fig (Carpobrotus edulis), a South African succulent documented at coastal natural sites, is classified as invasive both in the 2009 survey and on the government's ornamental-plant list.[1][2] Blue-leafed wattle (Acacia saligna) is likewise classified as invasive by both sources.[1][2]

Prostrate oxalis (חמציץ נטוי), also originating in South Africa, arrived in the region as an ornamental plant a little more than a century ago and subsequently spread along field and orchard margins and into fallow fields.[12] A January 2026 report described accelerating spread in forests, nature reserves, and other open areas, with the plant forming dense carpets on forest floors that alter environmental conditions and harm biodiversity.[13] In the Sharon region's Ilanot Forest, it had displaced nearly all local vegetation, including crimson iris, Hyacinth squill, showy lavender, Israeli lupine, and Tel Aviv garlic. A researcher said the plant releases acid that lowers local pH, potentially inhibiting the germination of other species.[13] The plant spreads primarily through underground bulbs rather than seeds.[13]

The split-leaf nightshade (סולנום שסוע), native to New Zealand, southeastern Australia, and Tasmania, was discovered in the burned area of Mount Tayasim Nature Reserve, the slopes of the Holy Forest, and Nahal Tayasim in the Judean Hills, two years after a 2021 summer wildfire.[14] It grows rapidly, reaches up to three meters, establishes readily after fires, and is dispersed by birds.[14] The Jewish National Fund and Israel Nature and Parks Authority conducted surveys and began targeted control efforts after its discovery; its presence on the Agriculture Ministry's ornamental-plant list despite its invasive behavior was noted as a concern.[14]

Eucalyptus camaldulensis (river redgum) is classified as naturalized on the government ornamental list, which cautions against planting it near streams, lakes, swamps, winter-rain ponds, springs, and areas of shallow groundwater.[2] Water hyacinth (Eichhornia crassipes) is classified as invasive on the same list.[2]

The inventories reviewed here do not provide a comprehensive, species-by-species list specifically defined as adventive wild plants in Israel.[1][11] Some sources cover surveys of natural and semi-natural areas, while the government ornamental-plant list is expressly limited to ornamental and forestry taxa and is not an exhaustive inventory of alien plants in natural habitats.[2] Other reports provide invasive-species totals without treating adventive plants as a separate category. Counts therefore vary with terminology, survey scope, location, and date.

Published estimates of Israel's flora also differ. A nature-conservation overview reports approximately 2,600 plant species, including 150 described as indigenous to Israel, while a separate overview reports approximately 2,800 wild-plant species, including 150 indigenous and about 250 endemic species.[3][4] These total-flora figures are not adventive-plant counts.