Please help! Weed identification

charlibeau

Hi everyone,
please can someone help me and identify these weeds? I’ve noticed them poking up in my new garden this week. 
Theres a lot of plastic sheeting down in the garden and I am worried that it may be invasive.
thanks so much 

Hostafan1

oh dear. Mares tail. Almost impossible to destroy I'm afraid.

charlibeau

Ah, bad news. Better get on it 
 
Thank you v much