Chrysocephalum semipapposum

Senecio pterophorus, African daisy

Funnily enough the clue was in today's "(not) parkrun results" newsletter. A photograph¹ of the weed in the foreground of two joggers who could be South African.

Then, given "tall thick stalk with yellow flowers weed in Australia" a search engine found the North Central Catchment Management Authority "Weeds Identification Guide"². See appendix A for description of winged groundsel.

Finally, the preferred habitat is described in the Agricultural Victoria biosecurity page³, copied into Appendix B.

Appendix A.

"(winged groundsel)Description: An erect, busy shrub 1–3 m tall.Flowers: Yellow and arranged in flat topped clusters at the end of stems. Each ‘flower’ contains up to 100 tiny tubular florets in groups 1–1.5 cm across. Flowers during late spring and summer.Leaves: Tapered, dark green above, leathery and woolly underneath. Up to 12 cm long and 7–20 mm wide. Clearly toothed along the edges and on short winged stalks or no stalks but a small wing on the main stem.Stems: Grey-green, becoming woody on the lower stem.Note: Highly invasive, autumn to spring growing and spreads by seed."

Appendix B.

"African daisy grows well in lowland grassland, grassy woodlands and dry sclerophyll forests.

It prefers humid and sub humid subtropical and warm-temperate savannahs, where it is mainly found on medium and lighter soil types.

It occurs as a weed of disturbed soils along roadsides and in denuded grazing land, newly-sown pastures, forest margins and wastelands. Also after events such as bushfires and clearing."

Ref:

¹ https://linksharing.samsungcloud.com/kenIwCZMC9wv

² http://www.nccma.vic.gov.au/search/node/weeds identification guide

³ https://agriculture.vic.gov.au/biosecurity/weeds/priority-weeds/african-daisy

It's not Senicio spp. It is likely to be a Chrysocephalum semipapposum. The daisy Chrysocephalum semipapposum Cluster Everlasting has been listed as indigenous to Nail Can Hill according to "Basix List of indigenous/ low water use plant species Albury".