Abrojo

Hi there, yet another veteran xcom player to come here 10 days have passed since i started the game (normal, v1.2), and i have spotted a planter and couldn't take it down. Now this happened just before i closed U:AM and then i came to this thread where ppl are saying i should see planters after a mission about "Area 51" and that if i dont shoot down this planter i would face this 'biomass' thing. Now just wondering is this normal?