pg . 68
NQ DRY TROPICS WEED FREE
BLUE THUNBERGIA
Thunbergia grandiflora
BLUE THUNBERGIA
DESCRIPTION
This is a vigorous perennial twining vine which grows to 15 metres . The branches are 4 angled . Leaves are up to 15 centimetres long and 10 centimetres wide and are arranged opposite each other along the stem . They are broad-based narrowing to a pointed tip , usually with deeply scalloped lobes towards the base . Flowers are trumpet shaped as a short , broad tube , which is white on the outside and yellowish inside . It expands to 5 rounded pale lavender-blue petals which are up to 8 centimetres long . It flowers throughout the year . Seed pods are cone shaped , 3 to 5 centimetres long with a rounded base . The seed is flat , small and covered with brown scales . Roots are tuberous and can grow to 70 kilograms . Habitat it is found in lowland rainforest and river systems , cleared land , and monsoon vine thickets Weed characteristics it forms impenetrable colonies . It climbs and blankets native vegetation often pulling down mature trees with its weight . It limits natural growth of lower layers of vegetation . It spreads quickly , and the large tubers may cause damage to structures . Dispersal plant segments can be transported in soil or fill as well as floodwaters along river banks .
BIOSECURITY MATTER
Restricted . This species is Category 3 Restricted matter under Queensland Legislation .
VINES
HOW TO ACT
A broad leaf herbicide should be used , however due to the underground tubers the plant often persists . Cut stumping can be used to allow access to large infestations . Hand pulling plant material will usually require follow up foliar spraying of regrowth . Care should be taken to monitor site as underground tuberous root system can often need direct injection of herbicide to completely control infestation .