I main a Combat Stormwarden HR. For me, I use gushing wound/throw caution/plant growth. This combination allows you to do buff everyone (lss or split the sky which gives combat advantage), debuff (throw caution) and do crazy amount of damage (gushing wound for single and plant growth for multiple targets). Rule of thumb, learn your feats, they are your best friends. Try to keep your self buffs going and keep flurry active. Generally 1 encounter follows by 2-3 at wills.

HR Stormwarden if played right can do crazy amount of damage both on mobs and boss (mod 15 buffs Blade Storm and Twin Blade Storm so expect more damage on mobs :). For starter, MMOminds is a really good place to go to. I personally would recommend you to check out KB or Sume's HR build and rotation on youtube. They are the best HRs you can find out there. Their explanations are more in depth than what I can provide and their works on HR is what inspires me to play Stormwarden Combat HR.

If you have any questions, my handle is @sorrrrrrrrrra#8470 , add me and we will learn HRs together.