Common heather

Key traits

Common heather has adventitious roots (Gimingham 1960). Rooting depth is variable and depends on soil type, in bog conditions root is typically in the top 10cm of the soil, whilst in drier soils this may be around 50cm, indicating that rooting depth in Calluna tends to link to the height of the water table (Gimingham and references therein 1960). Resprouting from belowground buds and remaining stems is found seen in young and vigorous plants however controlled burning may kill mature and degenerate plants at ages exceeding 15 years (Gimingham 1960)

Common heather seeds show smoke and ash stimulated germination (Vandvik et al. 2014; Maren et al. 2010). The seedbank is tolerant of low-severity fires but may be destroyed by severe fires (Maltby 1980). Seeds can travel considerable distances (e.g., 40m; Gilbert and Butt 2010).

Plant response to fire

Common heather can readily recolonize from large soil seed banks and via rapid vegetative resprouting after fire (Gimingham 1960) and prescribed fire is widely used in the UK to maintain areas of common heather.
 
Common heather shows variation in its fire-related traits. Smoke-induced germination is known from Calluna populations in anthropogenically burned coastal heathlands. However, of importance is that this trait is not present in all Calluna communities; it appears to occur in Calluna habitats that have high fire frequencies or a long history of anthropogenic use of fire. This record of anthropogenic burning of heathland dates back to the Neolithic and expanded from the Bronze Age, and controlled burning still remains in many Calluna-dominated ecosystems. Therefore, Calluna appears to have developed two ecotypes (or two ecophenotypes) that show evolutionary differentiation in germination according to whether or not they have been exposed to long-term anthropogenic burning regimes (Vandvik et al. 2014). Vandvik et al. (2014) noted that the distinct smoke-stimulated ecotype could be at risk if the land-use regime that supports Calluna disappears or semiregular fire is removed from the system. Similarly, Maren et al. (2010) noted that to maintain this ecotype heather burning would need to be continued or the addition of smoke solution to the soil or the use of smoke tents would be required to maintain this smoke-stimulated ecotype. The last two options are noted as being unable to provide open sites for germination, which also requires light. It is also noted that mowing or other mechanical approaches would be ineffective in stimulating the fire-adapted Calluna ecotype (Maren et al. 2010).

Timing of life history

Perennial species. Seeds likely produced from second growing season. Flowering August to November.