The Noxious Weeds Act is concerned with the clearing of specified weeds and the trimming of particular types of hedges (hawthorn, barberry, sweet brier, gorse, boxthorn, broom, hakea). Its administration is optional for county councils and certain road boards, but obligatory for all boroughs and certain town councils. In the First Schedule of the Act, which may be added to from time to time, 87 weeds out of the 600-odd species regarded as troublesome are listed, and any or all may be declared to be noxious weeds within the whole or part of the district of any local authority which administers the Act. The Act provides, inter alia, (i) for appointment of inspectors; (ii) rights of appeal by occupiers against requirements of inspectors; (iii) clearing of Crown, Maori, and local authority lands; (iv) penalties for continued default; (v) that it is an offence, without the consent of the Minister (or local authority when it administers the Act) to offer for sale, sell, sow, or propagate any seeds, cuttings, or plants of any species named in the First Schedule; (vi) that Bermuda buttercup (Oxalis pes-caprae syn. O. cernua) and nutgrass (Cyperus rotundus) must be cleared from registered plant nurseries (these weeds are not included in the First Schedule); (vii) that no person shall have in his possession any water hyacinth (Eichhornia crassipes); (viii) that an occupier is responsible for clearance of noxious weeds to the middle line of the road; (ix) that it is an offence to sell or sow uncleaned grain or seed; (x) that threshing machines, etc., must be cleaned before shifting from one property to another; and (xi) that local authorities may act together.

The Noxious Weeds Act of 1950 is administered by the Minister of Agriculture, and in districts where the local authority does not administer the Act, powers are exercised by officers of the Animal Health Division of the Department of Agriculture. Two other enactments concerned with weeds are also under the auspices of the Department of Agriculture – the Introduction of Plant Act of 1927, which legislates against the importation from overseas of any weed named in the First Schedule of the Noxious Weeds Act of 1950; and the Nassella Tussock Act of 1946, which provides for the control and eradication of nassella tussock (Nassella tri-chotoma), giving powers to county councils to act, and setting up two ad hoc bodies – the North Canterbury Nassella Tussock Board and the Marlborough Nassella Tussock Board – for the purpose.

Noxious Weeds

The weeds set out in the First Schedule of the Noxious Weeds Act are here listed, it being noteworthy that, apart from two exceptions (Tauhinu or New Zealand cotton wood, Cassinia leptophylla or Cassinia fulvida), all are adventive.

• Plants Which May be Declared to be Noxious Weeds

• Barberry (Berberis darwinii)

• Barberry (Berberis vulgaris)

• Barley grass (Hordeum murinum)

• Bathurst bur (Xanthium spinosum)

• Bindweed (Convolvulus arvensis)

• Blackberry (Rubus fruticosus and Rubus laciniatus)

• Boxthorn (Lycium ferocissimum syn. Lycium horridum)

• Burdock (Arctium, any species)

• Californian thistle, Canadian thistle, or creeping thistle (Cirsium arvense)

• Caper spurge (Euphorbia lathyris)

• Cape tulip (Homeria collina)

• Chamomile (Matricaria chamomilla)

• Charlock (Sinapis arvensis)

• Common broom (Cytisus scoparius)

• Crack willow (Salix fragilis)

• Cut-leaved psoralea (Psoralea pinnata)

• Dewberry (Rubus caesius)

• Fennel (Foeniculum vulgare)

• Field horsetail (Equisetum arvense)

• Foxglove (Digitalis purpurea)

• Giant buttercup (Ranunculus acer)

• Goat's rue (Galega officinalis)

• Gorse (Ulex, any species)

• Greater bindweed (Calystegia sepium)

• Grecian thistle (Chamapeuce afra)

• Grey willow (Salix cinerea)

• Hakea (Hakea saligna, Hakea suaveolens, Hakea pubescens, and Hakea acicularis)

• Hawthorn (Crataegus oxycantha and Crataegus monogyna)

• Heath (Erica lusitanica and Erica arborea)

• Hemlock (Conium maculatum)

• Hoary cress (Cardaria draba syn. Lepidium draba)

• Inkweed (Phytolacca octandra)

• Japanese wineberry (Rubus phoenicolasius)

• Johnson grass (Sorghum halepense)

• Kangaroo acacia (Acacia armata)

• Kangaroo grass (Themeda triandra)

• Knapweed (Centaurea nigra)

• Lantana (Lantana camara)

• Lily of the valley vine (Salpichroa oriabifolia (Lam.) Thell, syn. Salpichroa rhomboidea Miers)

• Lupin (Lupinus arboreus)

• Malta thistle (Centaurea melitensis)

• Manchurian wild rice (Zizania latrifolia)

• Milk thistle or variegated thistle (Silybum marianum)

• Mist flower or Mexican devil (Eupatorium adenophorum)

• Montpelier broom (Cytisus monspessulanus)

• Mountain hypericum (Hypericum montanum)

• Nassella tussock (Nassella trichotoma)

• Needle grass (Stipa neesiana)

• Nodding thistle (Carduus nutans)

• Oxylobium callistachys

• Pennisetum (Pennisetum macrourum)

• Prickly pear (Opuntia monacantha)

• Pultenaea daphnoides

• Pussy willow (Salix discolor)

• Ragwort (Senecio jacobaea)

• Russian knapweed (Centaurea repens)

• St. John's wort (Hypericum perforatum)

• Saffron thistle (Carthamus lanatus)

• Scentless chamomile (Matricaria inodora)

• Scotch thistle or plume thistle (Cirsium lanceolatum)

• Sedge (Carex longebrachiata syn. Carex longifolia)

• Silver poplar (Populus alba var. nivea)

• Spiderwort (Leycesteria formosa)

• Spiny broom (Calycotome spinosa)

• Squirrel grass (Hordeum jubatum)

• Star thistle (Centaurea calcitrapa)

• Stinking mayweed (Anthemis cotula)

• Sweet brier (Rosa eglanteria syn. Rosa rubiginosa)

• Tall cinquefoil (Potentilla recta)

• Tauhinu or New Zealand cotton wood (Cassinia leptophylla or Cassinia fulvida)

• Thorn apple or jimson weed (Datura stramonium)

• Tutsan (Hypericum androsaemum)

• Viper's bugloss (Echium vulgare)

• Water hyacinth (Eichhornia crassipes)

• Watsonia (Watsonia bulbillifera)

• Wild teasel (Dipsacus silvester)

• Wild turnip (Brassica campestris)

• Winged thistle (Carduus tenuiflorus and Carduus pycnocephalus)

• Woolly nightshade (Solanum auriculatum)

• Yellow star thistle (Centaurea solstitialis)

by Arnold John Heine, Antarctic Division, Department of Scientific and Industrial Research, Wellington.