Cordyline australis ‘Zuidland’ and ‘Groenland’
Cordylines are deservedly extremely popular in our gardens. There are many species out there, but most can only tolerate minus 7 degrees Celcius of frost for a limited time. A ‘pure’ Cordyline with a green leaf can take approximately -10C.
With little care and protection you can nurse your plant through a few more degrees of frost, but if the bad weather continues even the green Cordyline will eventually suffer. Usually Cordyline will recover; after light frost-damage new growth appears from under the frozen part. After severe damage it often even regenerates from the roots!
In New Zealand C. australis can be found from the North Cape to the sub-artic lands of the south – this is a range of several thousand kilometers. The most frost sensitive plants grow in the sub-tropical North Island. In the trade Cordylines probably originate from there to a large extent. However, the most hardy provenance is central Southland (North of Invercargill). Some isolated populations near Dipton are regularly exposed to severe frosts and have never been tried out here before. These populations have a slow, compact growth and are much hardier than their relations from the north.
Some of these hardy Cordylines have a reddish leaf after germination. I’ve called these ‘Zuidland’ (Dutch for ‘Southland’). After a few months the leaves turn green. The seedlings whose leaves are green after germination I’ve called ‘Groenland’. Testing both types in the jungle garden shows no difference in hardiness between these two variants.
C. australis ‘Zuidland’ and ‘Groenland’ prove hardy enough for mild, coastal areas in our western-European climate. Inland some protection will be necessary.
In harsh winters we’ve had some frost damage to the plants, particularly inland. The Cordylines from Southland are tougher but still need frost protection during severe cold spells.
NB in many garden centres C. australis is often misnamed C. indivisa.