How can I keep grass from growing in my flower bed I just want mulch?

weed barriers will be fine for awhile but eventually seeds land on top and grow. When mowing make sure you are sending the grass clippings shooting away from the bed. Fresh mulch and plenty every year. Pull when you see it start. Isolated round up but make sure the over spray does not touch plants.

Simplest way is to cover it with mulch-- as it grows, REcover it...eventually it will be 'exhausted' and die.

Apply mulch about 1-2" deep in the garden and BURY the weeds in 3" depth... If you loosen the weed's roots, you can accelerate the death.

Really, you're using the right stuff for chemical-free gardens... you just need a bit of persistence! Go At it!

I think people expect that once they have established a grass and weed free garden--it's going to stay that way! Wishful thinking! It is an ongoing job. Spraying with Round up, weeding and adding mulch will eventually result in a garden space that becomes easier to maintain over time--you will still have to pull out grass and weeds but it should be minimal as time passes--as long as you maintain a maintenance schedule in the spring and fall.

Lay thick layers of newspaper or brown grocery bags down, soak them with water, then cover with mulch. I just tried this last year and have only a few weeds that sneaked through.

newspaper,cardbaord,heavy landscape fabric and top with mulch

I wouldn't put plastic under the mulch; just thick newspapers. You want the earth worms to have access to the weeds, newspapers and compost so they will turn it over, kill the weeds And enrich the soil. If you can, make a raised bed, then put compost topped with mulch and let the worms do what they do best. You can plant your Hostas and have a worm workforce at the same time. And GK is right. Seeds blow in, and/or are dropped by birds so weeding and mulching is an ongoing part of gardening.

weed killer along the edge