Jasminum nudiflorum; bright yellow flowers on chlorophyll green stems. This one, a stem layer that caught itself under the fence post and rooted into the mortar joint. The parent plant was grubbed out and a small section of stem trapped remained to grow and thrive in what appears the most inhospitable of growing conditions. A native to China from where it was introduced to Britain in 1844 by Robert Fortune. On this south facing wall the wood ripens and it produces flowers from November through to February. Keep an eye out for these strivers; Buddleja and Cotoneaster being the most often observed. Multi stemmed Buddleja growing on walls, seen reaching two metres in height are not uncommon. Seeds eaten and excreted by birds are the usual reason for woody and other seedlings establishing in the most unlikely of environments. Be aware that eventually the force of root growth will damage mortar joints and lead to the ingress of moisture.