This card works great with Tangrowth or Eggs. It's only disadvantage is it's Weakness.
The Retreat Cost is acually 2, because of the Body. Is that too bad? No. So, stop complaining, 2 RC is average in this format.
The attack is okay. It costs 2 Energy because of it's Body, and can do 50 - 70 damage, with a coin flip. This can be an annoyer, getting up quicker then those Gard/Lades and hitting them for 50 or 70. However, it's not a very powerful attack. 70 max isn't that great, even for 2 Energy. If it had a second attack, it might be better.
The HP isn't too hot. 100 isn't too good nowadays, the format's made up of 110 and 130 HP boys. If it had 110 HP like Gardevoir, it would see much more play, but... so, this is another weak point.
The Body is the only reason worth playing it. All Grass Energy attached to all of your Grass Pokemon now provides 2 Grass Energy. Nothing more needs to be said.
8/10