The life cycle of serrated tussock

Serrated tussock is a perennial plant, meaning it grows for two years or more. Serrated tussock moves through its lifecycle by germinating, producing seedlings, progressing through active growth, where it flowers then seeds, repeating the cycle.

The general growth pattern of serrated tussock can be seen in the table below. 

Note: The timing of different stages can vary depending on temperature, rainfall and soil fertility. Source: National Serrated Tussock Best Practice Manual 2008.

GERMINATION -  Step 1

Germination mainly occurs through autumn and winter, but may occur at anytime in the year following significant rainfall and in response to soil disturbance.

SEEDLINGS - Step 2

Seedlings are weak and slow growing and more likely to establish on bare ground with limited competition. Their establishment is critical over the summer months. It is during this time that if the seedlings become stressed by competition for moisture or light, their chance of survival is reduced.

Seedlings are likely to establish on bare ground with limited competition. - Source: Michael Michelmore 

ACTIVE GROWTH - Step 3

Established serrated tussock plants actively grow in favourable autumns and in spring and early summer when sufficient soil moisture is available.

FLOWERING - Step 4

Flowering stems emerge from the base of the tussock as early as late winter and will continue throughout the spring. The flowering stem/seed head is a panicle (multi-branched) up to 35cm long. The purple colour of the seeds produces an overall purplish haze to the serrated tussock seed head. Once the seeds have formed, the entire seed head will droop over the tussock towards the ground. 

Serrated tussock flowers in Spring and early Summer. - Source: VSTWP 

 

 

SEEDS - Step 5

Seeds take eight to ten weeks to mature once the flowering stems emerge. This will normally occur throughout the spring and summer months. Once seeds are ripe, the whole flowering stem detaches from the base of the plant and is dispersed by the wind. Seed is dormant when first dispersed and will not germinate until dormancy has broken (approximately six months). 

Serrated tussock in seed. - Source: VSTWP 

BLEACHING - Step 6

Bleaching from frost may occur in late autumn and winter, turning the plant golden yellow in colour – which can help with identification in winter.

More information can be found in the in the National Serrated Tussock Best Practice Manual and the VSTWP Identification of serrated tussock guide.   

Frost can bleach the leaves of serrated tussock. - Source: Malcolm Campbell

More information can be found in the in the National Serrated Tussock Best Practice Manual and the VSTWP Identification of Serrated Tussock guide.