two-colored headlines

I want to have two-colored headlines in wordpress. for example: “our appletree” – with our in blue and apple in red.

Of course i could use <h1><span>our</span>appletree</h1> and color the span in another way than the rest. but that’s nor correct from semantic, seo and validation perspective. and poorly there’s no :first-word css pseudo-element.

Is there any possibilty or plugin to get this working? Maybe some kind of prefix being set in front of the headline, so “our” would be the prefix in this case, being followed be “<h1>appletree</h1>”…

Or other solutions?