Petty whin

Key traits

Petty Whin regenerates following fire of low-moderate severity by re-sprouting from root crowns and following higher severities also by seedling establishment. Although vegetative regrowth of Petty Whin has been noted to be unrelated to aspects of fire intensity (Mallik and Gimingam, 1985). New shoots have been observed to grow from surviving stem bases even in fires measuring 400-800°C, where the ‘lack of obvious adverse effects’ of high temperatures on this species might be mitigated by its bark thickness (Mallik and Gimingham, 1985).

Petty Whin has seeds with a hard seed coats, which are likely to be long-lived in the seedbank (similar to closely-related species Scotch Broom with a 5 - 30 year longevity; Zouhar, 2005 and references therein).
Seed production is similarly assumed to be high (Allen et al., 1995). Seeds require scarification before germination (Zouhar, 2005). Owing to the need for scarification Petty Whin has been noted as having seeds that are stimulated by heat from fire. Seeds of Petty Whin were shown to increase germination upon heating with 96% of seeds germination when heated at 100oC for 2 min (Mallik and Gimingham, 1985).

Plant response to fire

Owing to seed stimulation by fire Petty Whin can increase its abundance post-fire. It has been suggested that prescribed burning of closely-related species, Scotch Broom, could increase germination and decrease seed bank density at the soil surface, depending on the duration of heating and temperatures reached during the fire. This is likely to be similar for Petty Whin.

Timing of life history

Perennial species. Seeds likely produced from the second or third growing season. Flowering May to June.