Vines Growing as Shrubs in Open Situations

A number of vines can grow as shrubs in open situations where there is no support. This is particularly the case with the small, unspecialised, scrambling species, as well as the small twiners Muehlenbeckia complexa and Parsonsia capsularis, both of which are able to make an easy transition from well lit forest margin and shrubby habitats to completely open sites. As shrubs these species often have a ball-like form with a profusion of slender, entangled stems.

Some of the taller, more specialised forest vines may also grow as shrubs. Rubus squarrosus has been already mentioned. Several of the climbing ratas (Metrosideros) can also be encountered as shrubs. M. perforata in particular has a dense, billowy form, which gives no hint of any ability to climb. Such dual roles are not peculiar to New Zealand vines, but have also been observed in a number of tropical lianes.²¹