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 a 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 points appear from under the frozen part. After severe damage it often even regenerates from the roots!

In New Zealand C. australis appeard from the North Cape to the sub-artic lands of the south - this is a range of several thousand kilometers. The most sensitive plants to frost grow in the sub-tropics of the North Island. Our pot plants probably originate from there to a large extent. However, the stronger plants are to be found on the southern island to the North of Invercargill. Some isolate populations are regularly exposed to severe frosts there and have never been tried out here before. These populations grow more compactly and more slowly than their relations from the north.

Some of these hardy Cordylines have a reddish leaf after germination. I've called these 'Zuidland' (Dutch for 'Southern land'). After a few months the leaves turn green. The seedlings whose leaves are green after germination I've called 'Groenland'. I've established through inquiry in New Zealand that there's no known difference in hardiness between these two variants.

I estimate that 'Zuidland' and 'Groenland' will prove hardy enough for mild, coastal areas in our western-European climate. Inland some protection will be necessary.
We'll have to see whether there's any variation in hardiness between these two plants here! In recent winters we've had damage to the plants, particularly in the south of Holland. So they're not really winter-hardy but could be said to be frost-resistant.