cordyline, nigra variety

I was just wondering what are the best growing conditions for a cordyline, nigra variety?
mine is starting to look a bit crappy as if its frost bitten, but they thrive in winter though?
is there any fertilizer or anyhting i should put on it?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.