Rhamnus alaternus
NPPA pest plant
Environmental Weed (2024)
Common names
Italian evergreen buckthorn
Family
Rhamnaceae
Flora category
Vascular – Exotic
Structural class
Trees & Shrubs - Dicotyledons
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
RHAALA
Conservation status
Not applicable
Habitat
Terrestrial. A plant of coastal and lowland habitats, grows in sites with low - low/moderate fertility. Invades scrub, forest margin, tall forest, low forest, shrubland, fernland, cliff and bare rock and river verge communities.
Detailed description
Evergreen shrub to approx. 5m high, often < 1m in exposed sites. Shoots angular, hairy, usually purple when young. Stipules subulate. Petiole 3-11mm long, hairy, at least on upper side. The leaves are leathery, often toothed glossy and oval to about 6cm long. The flowers are small, green and fragrant. The berry is up to 7mm long, broad, ovoid, glossy red becoming black with a stone.
Similar taxa
May be confused with Melicytus novae-zelandiae (endemic) in northern coastal areas. The purplish stems and fruits of Rhamnus alaternus are quite distinctive. Rhamnus cathartica is also cultivated in NZ, but is not known from the wild. R. cathartica has more ovate leaves than R. alaternus.
Flowering
May, June, July, August, September, October, November
Flower colours
Green
Life cycle
Perennial. Can spread vegetatively underground and by seed. Seed is produced at the rate of 3 seeds/fruit and 10 000 plus fruit per 8m tall individual (Timmins & MacKenzie 1995). Seed is thought to remain viable in the seed bank for three years (Wotherspoon 1996). The seed is dispersed by birds.
Year naturalised
1940
Origin
Mediterranean
Reason for introduction
Ornamental
Tolerances
Highly tolerant of drought, shade and frost and tolerant to poor drainage. Physical damage, grazing and fire results in resprouting of the plant. After fire large leafy watershoots are produced from the base of the tree. Requires low to medium soil fertility.
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Environmental Weed (2024)
This plant is named in a list of environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
References and further reading
Timmins & MacKenzie 1995
Wotherspoon 1996