Watch the Strumming Options online guitar lesson by Rich Maloof from Acoustic Guitar For Beginners
An entirely new type of right-hand movement combines plucked and strummed strings. For this you will definitely need to know which is the lowest string you can pluck, so mind those chord grids and watch out for strings that should not be played at all (marked with an X).
This right-hand action first plucks the lowest note, then proceeds with a strum. It has a lilting feel. In its most basic form it seems like a country 'n western rhythm. The technique has broader applications as you expand on it with variations.
(Note: the word "root" is often misused to describe the lowest note of a chord. However, the root note really tells you the NAME of the chord. For example, "E" is the root note in an E chord, or an E minor, or an E7. Sometimes, the lowest note is not the root but another note from the chord.)