- 遙かな：adjective - 遙かな「彼方／遠方／昔(these are "direction" or "direction of time") -> you can skip ’な' and　’遙か' sounds like adverb. - 遙かな「山、故郷、町（these are real thing」 -> you cannot skip 'な'. The word must remain adjective. - in the context where you can feel 'flowing', you can say the following はるか草原をひとつかみの雲が あてもなくさまよい飛んでいく

はるか means "far", "long", or "much" as a degree or an extent. As you know, "はるか彼方" and "はるか遠方" means "faraway", "in the distance" or something like that, and "はるか昔” means "long ago". "はるか山” and "はるか故郷" don't include those kinds of words as "far", "long", or "much". I suppose that it is the reason why you cannot say "はるか山” and "はるか故郷". However, you can say "はるかな故郷の空" (the distant sky of home) if you use the word "はるかな” (distant) as an adjective.