A profile of this little known relative of Cordyline
australis. by Peter Richardson, Advanced Technologies Ltd.,
Science Park, Cambridge, U.K. Chamaerops No. 11, published online 23-09-2002
Above: Wild plants of Cordyline banksii in the
Kauaeranga Valley, New Zealand
Below: Cordyline banksii in cultivation in Cambridge (left). On
the right is Cordyline australis
I thought I would bring this New Zealand species
of cabbage tree to the attention of Chamaerops readers because it
seems to be the Ignored Species. Garden centres the length of the
U.K. sell C australis, even where it has little hope of surviving
outside, and enthusiasts pay inflated sums for plants of C indivisa
and C. caspar, but no one pays any attention to C banksii, even
in New Zealand.
It has a unique combination of an elegant, 'tropical'
appearance with at least equal frost hardiness to the provenances
of C. australis commonly grown in the U.K. Its looks ally it with
the tropical C. terminals in that the leaves are inserted in just
two twisted ranks, opposite and alternate, and are differentiated
into a distinct, long petiole and a blade, as opposed to the yucca-like
leaf insertion of C. australis, C. indivisa and C. caspar.
It is not a compact plant; on my largest plant growing
outdoors in Cambridge the petioles are 40cm long and the blades
are up to 120cm long, so the leaves are 1.6m long altogether. This
gives the crowns a significantly larger spread than those of C.
australis, and they can in fact be a problem to accommodate in a
small garden. The petioles have a U-shaped cross section and are
held at an acute angle to the stem, and the blades, which have a
pronounced midrib, flop out and down gracefully. They have a shiny
upper surface. The two ranks of leaves only start to twist after
the first year in most individuals, so young plants have a striking,
flat, fan-like array of leaves in the manner of the Traveller's
Palm, Ravenala madagascariensis. The twist gradually tightens as
the trunk grows taller.