Present distribution
| Map showing the present distribution of this weed. | ||||
Habitat: Occurs between 0 and 328 feet (Calflora 2010). Grows in coastal sites on a range of substrates (Bayly and Kellow 2006). Grows equally well in sun or light shade; will tolerate dry conditions quite well (Metcalf 2006). Coastal cliffs and headlands, in low windswept scrub and flaxland; rarely under taller trees (Waikato 2006). An established escape from cultivation on coastal cliffs and walls, also sand dunes; more rarely on waste ground (Bot Gardens Ireland 2010). The plant prefers light (sandy) and medium (loamy) soils, requires well-drained soil and can grow in nutritionally poor soil; prefers acid, neutral and basic soils and can grow in very alkaline soil. It cannot grow in the shade; requires moist soil (Plants Future 2010). High tolerance to frost; low tolerance to waterlogging (TRC 2004). Growing along the margins of a seepage (Metcalf 2006). |
Map Overlays Used Land Use: Forestry; horticulture perennial Ecological Vegetation Divisions Coastal; heathland; grassy/heathy dry forest; treed swampy wetland; granitic hillslopes; rocky outcrop shrubland; semi-arid woodland; alluvial plains woodland Colours indicate possibility of Hebe speciosa infesting these areas. In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable. |
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QUESTION | COMMENTS | RATING | CONFIDENCE |
Social | |||
1. Restrict human access? | Common hedging plant which seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). High nuisance value. People and/or vehicles access with difficulty. | MH | MH |
2. Reduce tourism? | A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). However, as the species epithet and common name suggest, Hebe speciosa (showy speedwell) has some aesthetic appeal (see Hutchins 1997; Bayly and Kellow 2006), and therefore is unlikely to reduce tourism. Minor effects to aesthetics and/or recreational activities. | ML | MH |
3. Injurious to people? | Branches of this plant are glabrous (Bayly and Kellow 2006), with no spines or thorns (Learn 2 Grow 2006–2010). No effect, no prickles, no injuries. | L | ML |
4. Damage to cultural sites? | Established escape from cultivation; more rarely on waste ground and rubbish tips where it can regenerate from discarded branches; also freely reproducing from seed, and seedlings in profusion near mature plants; spreading occasionally to walls and roadsides; common hedging plant (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground (Waikato 2006). Moderate structural effect. | MH | MH |
Abiotic | |||
5. Impact flow? | Hebes form an extensive system of fibrous roots (Bayly and Kellow 2006). Found growing along the margins of a seepage (Metcalf 2006), but has low tolerance to waterlogging (TRC 2004). Otherwise this plant is essentially a terrestrial species. Little or negligible effect on water flow. | L | MH |
6. Impact water quality? | Found growing along the margins of a seepage (Metcalf 2006), but has low tolerance to waterlogging (TRC 2004). Otherwise this plant is essentially a terrestrial species. No noticeable effect on dissolved O2 or light levels. | L | MH |
7. Increase soil erosion? | Hebes form an extensive system of fibrous roots (Bayly and Kellow 2006). A perennial, evergreen plant. Low probability of large-scale soil movement or decreases the probability of soil erosion. | L | MH |
8. Reduce biomass? | A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). Occurs on sea cliffs and steep slopes, either in open sites or amongst low scrub; a popular garden plant (DoC NZ 2004). Biomass may increase. | L | MH |
9. Change fire regime? | Hebe speciosa listed as having low flammability (Chladil and Sheridan 2003). H. speciosa is a fire retardant plant (Cradoc Nursery 2010). Occurs on sea cliffs and steep slopes, either in open sites or amongst low scrub; a popular garden plant (DoC NZ 2004). Small or negligible effect on fire risk. | L | M |
Community Habitat | |||
10. Impact on composition (a) high value EVC | EVC = Dry Valley Forest (V); CMA = West Gippsland; Bioregion = Highlands-Southern Fall; VH CLIMATE potential. Common hedging plant which seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, of Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers).ten layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). | MH | MH |
(b) medium value EVC | EVC = Sand Heathland (D); CMA = Wimmera; Bioregion = Wimmera; VH CLIMATE potential. Common hedging plant which seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers). | MH | MH |
(c) low value EVC | EVC = Rocky Outcrop Shrubland (LC); CMA = Wimmera; Bioregion = Greater Grampians; VH CLIMATE potential. Common hedging plant which seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). Major displacement of some dominant spp. within a strata/layer (or some dominant spp. within different layers). | MH | MH |
11. Impact on structure? | Common hedging plant which seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground. Branchlets stout, pliant, glabrous (Waikato 2006). Minor effect on >60% of layers or major effect on <60% of the floral strata. | MH | MH |
12. Effect on threatened flora? | Impact on threatened flora has not yet been determined. | MH | L |
Fauna | |||
13. Effect on threatened fauna? | Impact on threatened fauna has not yet been determined. | MH | L |
14. Effect on non-threatened fauna? | Impact on non-threatened fauna has not yet been determined. | M | L |
15. Benefits fauna? | Common hedging plant; seeds freely, with seedlings in profusion near mature plants (Bot Gardens Ireland 2010). A spreading shrub up to 2 x 3 m. Branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground (Waikato 2006). Some indigenous birds have been observed visiting flowers of Hebe speciosa (Armstrong and de Lange 2005). Provides some assistance in either food or shelter to desirable species. | MH | MH |
16. Injurious to fauna? | Branches of this plant are stout, becoming woody at base; branchlets stout, pliant, glabrous (Waikato 2006), with no spines or thorns (Learn 2 Grow 2006–2010). No effect. | L | ML |
Pest Animal | |||
17. Food source to pests? | The species is predominantly entomophilous, though some indigenous birds have been observed visiting flowers of Hebe speciosa (Armstrong and de Lange 2005). The flowers are hermaphrodite, and are pollinated by bees (Plants Future 2010). H. speciosa produces copious quantities of nectar (Bayly and Kellow 2006). Supplies food for one or more minor pest species. | ML | MH |
18. Provides harbour? | A spreading shrub up to 2 x 3 m; spreading to sprawling, rarely erect. Threatened by browsing animals (Waikato 2006). Population decline has been attributed to several factors including browsing by feral mammals (Armstrong and de Lange 2005). Capacity to provide harbour and permanent warrens for foxes and rabbits throughout the year. | H | H |
Agriculture | |||
19. Impact yield? | An established escape from cultivation on coastal cliffs and sand dunes; more rarely on waste ground (Bot Gardens Ireland 2010). Occurs on sea cliffs and steep slopes, either in open sites or amongst low scrub. A very popular garden plant (DoC NZ 2004). This plant is not recorded to be a problem in agricultural environments. Little or negligible effect on quantity of yield. | L | M |
20. Impact quality? | This plant is not recorded to be a problem in agricultural environments (see Impact yield?). Little or negligible effect on quality of yield. | L | L |
21. Affect land value? | Established escape from cultivation; more rarely on waste ground and rubbish tips (Bot Gardens Ireland 2010). Occurs on sea cliffs and steep slopes, either in open sites or amongst low scrub. A very popular garden plant (DoC NZ 2004). Little or none. | L | ML |
22. Change land use? | Established escape from cultivation; more rarely on waste ground and rubbish tips (Bot Gardens Ireland 2010). Occurs on sea cliffs and steep slopes, either in open sites or amongst low scrub. A very popular garden plant (DoC NZ 2004). This plant is not recorded to be a problem in agricultural environments (see Impact yield?). Little or no change. | L | ML |
23. Increase harvest costs? | This plant is not recorded to be a problem in agricultural environments (see Impact yield?). Little or none. | L | L |
24. Disease host/vector? | Hebe speciosa is listed as a host to plant pathogen Septoria exotica in Hawaii (Starr and Starr 2005; Wu et al. 1996). Host to major and severe disease of important agricultural produce. | H | MH |
QUESTION | COMMENTS | RATING | CONFIDENCE |
Establishment | |||
1. Germination requirements? | Germinate at a temperature of 21°–23°C germination takes three to four weeks (Gardeners Almanac 2005–2010). Seeds of Hebe spp. are not dormant and germinate readily in the light (Mackay et al. 2002). Hebe seeds usually germinate quite easily; germination usually takes place within 10–30 days of sowing; a good percentage of seeds should germinate (Metcalf 2006). On waste ground and rubbish tips where it can regenerate from discarded branches (Bot Gardens Ireland 2010). H. speciosa required light and a temperature of 25º C for germination; 78% after 5 weeks (Simpson 1976). Requires natural seasonal disturbances. | MH | MH |
2. Establishment requirements? | Grows equally well in sun or light shade (Metcalf 2006). The plant prefers light (sandy) and medium (loamy) soils; requires moist, well-drained soil, and can grow in nutritionally poor soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very alkaline soil. It cannot grow in the shade; can tolerate maritime exposure and atmospheric pollution; intolerant of drought (Plants Future 2010). Can establish under moderate canopy/litter cover. | MH | M |
3. How much disturbance is required? | Found in disturbed urban areas below 100 m (Jepson 2010). Grows in coastal sites on a range of substrates (Bayly and Kellow 2006). Established escape from cultivation on coastal cliffs and walls, also sand dunes; more rarely on waste ground and rubbish tips where it can regenerate from discarded branches; freely reproducing from seed, and seedlings in profusion near mature plants; spreading occasionally to walls and roadsides (Bot Gardens Ireland 2010). Establishes in highly disturbed natural ecosystems. | ML | MH |
Growth/Competitive | |||
4. Life form? | Spreading low or bushy to 1(–2) m tall; spreading or ascending branches (Bayly and Kellow 2006). Rounded shrub 1-2 m. tall. Branchlets stout, glabrous (Moore and Edgar 1970). Spreading shrub up to 2 x 3 m; branches stout, becoming woody at base, spreading to sprawling, rarely erect, often layering on contact with ground (Waikato 2006). Other. | L | MH |
5. Allelopathic properties? | Literature searches failed to locate references linking allelopathy with the genus Hebe. | M | L |
6. Tolerates herb pressure? | Threatened by habitat loss through actions including browsing from domestic stock and possums (DoC NZ 2004). Threatened by weed invasion of its coastal habitat, and browsing animals (Waikato 2006). Browsing by feral mammals a contributing factor to population loss and decline (Armstrong and de Lange 2005). Consumed and recovers slowly. | ML | H |
7. Normal growth rate? | Hebe speciosa a hardy, quick growing and easily maintained plant (Northland Natives 2007). Fast growing shrub (Learn 2 Grow 2006–2010). Rapid growth rate that will exceed most other species of the same life form | H | ML |
8. Stress tolerance to frost, drought, w/logg, sal. etc? | Hebe speciosa frost tolerant to -7º C (Warrington and Southward 1995). A frost hardy shrub (Page and Olds 1998). Rather frost tender, and will not withstand severe frosts; grows equally well in sun or light shade; will tolerate dry conditions quite well, but is much happier in moist soil; growing along the margins of a seepage (Metcalf 2006). Succeeds in most soils so long as they are not boggy or too dry; intolerant of drought; cannot grow in the shade (Plants Future 2010). High tolerance to salt wind, drought, frost (will tolerate frost of -7ºC or lower); low tolerance to waterlogging (TRC 2004). Drought, pollution and salt tolerant shrub (Learn 2 Grow 2006–2010). Hebe speciosa listed as having low flammability (Chladil and Sheridan 2003). Literature contains conflicting references regarding drought tolerance of this plant. Highly tolerant of at least two of drought, frost, fire, waterlogging and salinity, and may be tolerant of another. Susceptible to at least one. | MH | MH |
Reproduction | |||
9. Reproductive system | Flowers are hermaphroditic and thought to be predominantly outcrossing, suggesting some degree of self incompatibility. The species is predominantly entomophilous, though some indigenous birds have been observed visiting flowers. Plants can also spread vegetatively, forming clonal masses resulting from the layering of branches (Armstrong and de Lange 2005). Freely reproducing from seed, and regeneration from discarded branches (Bot Gardens Ireland 2010). Both sexual and vegetative reproduction. | H | H |
10. Number of propagules produced? | Calculations based on the description of H. speciosa by Bayly and Kellow (2006) indicate that the number of propagules produced per flowering event would well exceed 2000. | H | H |
11. Propagule longevity? | Capsules can be found throughout the year (DoC NZ 2004). Seeds of Hebe spp. are not dormant and germinate readily in the light (Mackay et al. 2002). Freely reproducing from seed, and regeneration from discarded branches (Bot Gardens Ireland 2010). Capable of vegetative reproduction. | L | MH |
12. Reproductive period? | Prolonged display of flowers over many months of the year (Metcalf 2006). Flowering occurs from January to October. Capsules can be found throughout the year (DoC NZ 2004). H. speciosa is a perennial, evergreen plant. Mature plant produces viable propagules for 3–10 years. | MH | ML |
13. Time to reproductive maturity? | No specific information available. | M | L |
Dispersal | |||
14. Number of mechanisms? | Plant material may have been dispersed as a trade item by Maori peoples (Armstrong and de Lange 2005). A popular horticultural specimen (Page and Olds 1998). Propagules spread by attachment to humans. | MH | H |
15. How far do they disperse? | Plant material may have been dispersed as a trade item by Maori peoples (Armstrong and de Lange 2005). A popular horticultural specimen (Page and Olds 1998). Very likely that at least one propagule will disperse greater than one kilometre. | H | H |