What can I use to stop grass from growing surrounded by my flower bed? I have tried the plastic that you buy but grass somehow...

I have tried the plastic that you buy but grass somehow grows right through it...the grass puncture the plastic...is in that is anything else?
Answers:    you say its a flower bed do you plant singular seasonal displays in it? or is it undying planting ? if you remove the plants after flowering etc before you replant i would spray the grass next to a glyphosate based weedkiller such as roundup spray it to manufacturer instructions on a calm time and avoid spraying near by plants after 7 days you can replant within the flowerbed the weedkiller is translocated which means it will travell through the palm leaf and down to the roots and kill the grass . If its irredeemable planting i would try to dig out the grass or possibly paint the grass with the weedkiller using an aged paint brush wearing suitable gloves
7-9 layers of tabloid, mulch (or put dirt) on top. Grass and weeds won't grow up through it, but seed will start on top...easy to verbs seedlings. I've found treatise more effective than expensive outlook fabric.