A beautiful plant @ctrl-alt-nwo and all proteas require extremely well drained soil which is both acidic and very low in nutrients (i.e. fertiliser containing phosphates kills them). Proteas will quickly die if their roots sit in waterlogged or wet ground for long periods in areas of high rainfall.

In the main feeding is not necessary providing you keep potting your protea on regularly each year with fresh compost. Any fertiliser containing phosphates is dangerous but there are slow release (8-10 month) granular fertilisers which can be used. However most pre- mixed acidic composts will already contain slow release fertiliser.

In general don’t unless you particularly need to shape up your plant or to remove damaged stems. Proteas can be cut back to the base and will re-grow perfectly well. However this is advisable only if the leaves of the plant have been frosted and then quick action is needed to encourage the plant to reshoot.

http://www.burncoose.co.uk/site/content.cfm?ref=Protea+-+Care+Guide