Plant/Kin

Kinetics is a late-blooming set -- two of your best powers come at 35 and 38. Plant/Kin is an awesome build, especially if you team with a good scrapper or tank who will herd up the foes in a tight group, so you can hit them all with Seeds of Confustion+Roots, then use your Siphon Power and Siphon Speed, Transfusion as needed. Your teammate(s) will love you if you keep them Speed Boosted, and it will help the team kill everything much faster. Later when you get Transfusion and Fulcrum Shift, you will be able to cruise through large groups.

After you get Roots early and then Seeds at 8, your next great Plant power is Carrion Creepers at 26. That will add a lot of damage and draw aggro, making it easier to solo if you want. Transfusion can take care of your, and everyone else's, endurance problems, and then Fulcrum Shift will kick your damage way up.