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Detailed information sheet


Botanical name :
Hieracium species
Family :
Asteraceae (daisy) family
Common name :
hawkweed
Also known as :
mouse-eared hawkweed (H. pilosella), orange hawkweed (H. aurantiacum), king devil (H. praealtum), field hawkweed (H. caespitosum), tussock hawkweed (H. lepidulum), spotted hawkweed (H. pollichiae), H. argillaceum, H. murorum, H. sabaudum, H x stoloniflorum.
Where is it originally
from? :
Europe
What does it look like? :
Perennial herbs that form mats of tight, interconnected rosettes with thick underground root systems, and often with above-ground root systems (stolons) as well. Leaves (25-150 x 6-50 cm) are dull green to dark green above, usually paler (occasionally purplish) below, with those at the base of the plant usually slightly toothed, and with bristly hairs above and star-shaped hairs below. Thin stems (10-75 cm) have milky sap. Lemon or yellow dandelion-like flowers appear from October to May (orange, purple when dry, in H. aurantiacum and H. x stoloniflorum), which occasionally have red stripes on outer face. Seeds with fluffy, dirty-white hairs (4-8 mm) also appear from October to May.
Are there any similar
species? :
Hawksbeard (Crepis),hawkbit (Leontodon) and catsear (Hypochoeris) species.
Why is it weedy? :
Grows and matures quickly, producing many moderately long-lived and widely dispersed seeds. Creeping, mat-forming habit enables it to tolerate damage and grazing, moderate to cold temperatures, low rainfall, poor soils, and little shade. It produces substances in the soil that discourages other species from growing near it (allelopathic).
How does it spread? :
Seed is spread by wind, and in clothing and animal pelts. Root fragments are spread by water movement, contaminated soil and machinery.
What damage does it do? :
Forms dense, long-lived mats in low-growing plant communities (for example, H. lepidulum in beech forest), excluding almost all other species.
Which habitats is
it likely to invade? :
Disturbed shrubland and forest, beech forest, tall and short tussockland, fernland, alpine and volcanic plateau herbfields, bare land, riverbeds and streambanks, and rocky outcrops.
What can I do to get
rid of it? :
1. Ensure biocontrol agents are present wherever possible.
2. Weed mat: lay for three months minimum, maintaining a ‘rolling front’ towards the infestation.
3. Dig out small patches (all year round): dispose of rhizomes.
4. Weed wipe (during active growth): clopyralid (1L/10L) or 2,4-D butyl ester (2L/10L) or metsulfuron-methyl 600g/kg (5g/L) or MCPA (2L/10L) or Granstar (5g/L).
5. Spray (during active growth): metsulfuron-methyl 600g/kg (5g/10L) or dicamba (100ml/10L) or clopyralid (25ml/L) or 2,4-D butyl ester (50ml/10L) or MCPA (100ml/10L) or Granstar (30g/10L).
What can I do to
stop it coming back? :
Rhizomes and stolons resprout after spraying or digging. Seeds in soil germinate on bared sites. Planting a dense band of shrubs at infestation edge can prevent vegetative spread. Exclude livestock at all times as healthy tussock communities are less likely to become infested (H. lepidulum will invade intact tussock, shrubland and forest). Begin control at windward end (at seeding time) of infestation. Combination of the above methods may improve competitiveness of native species.

 

For more detailed botanical descriptions of weed species, check out the Plant Conservation Network's website at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index.asp

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*The chemical control methods in this manual were devised by Department of Conservation staff for Department of Conservation operations and should not be used as a substitute for the pesticide manufacturer's label instructions. The Department of Conservation takes no responsibility for any liability or damage to any person, property or thing which may occur as a result of the use of any pesticide in accordance with the chemical control methods contained on this website.

 

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