Watch the Arpeggiated Chords online guitar lesson by TrueFire from Play Rock Guitar 8: Advanced Rhythm Principles
Arpeggiated Chords - Breakdown is a video guitar lesson presented by Jennifer Batten and is sourced from Rock Sauce for Rhythm Guitar.
The technique of combining open strings with fretted notes is very common in country style guitar playing. It adds another level of lushness to an arpeggiated chord. I've also used string slides and hammer ons while arpeggiating, to add more notes. Another technique here is to play a D major triad chord made of harmonics.