Need a grass killer for flower bed so it won't hurt the flowers-ideas?

I have found the Preen products are pretty helpful. Check out reviews and the Q&A here to see if it could be used for your gardens weed eradication needs. There are different formulations to include organic.

https://www.amazon.com/Preen-Garden-Weed-Preventer-Covers/dp/B000GXQMEE

https://www.amazon.com/Preen-Garden-Preventer-Power-Spreader/dp/B007C7I13M/ref=pd_sim_86_3?_encoding=UTF8&pd_rd_i=B007C7I13M&pd_rd_r=M14SNMH8Y2CV5XB8J4Q3&pd_rd_w=8BdSE&pd_rd_wg=6hduF&psc=1&refRID=M14SNMH8Y2CV5XB8J4Q3

https://www.amazon.com/Preen-Extended-Control-Preventer-Covers/dp/B074J5699N/ref=pd_bxgy_86_img_3?_encoding=UTF8&pd_rd_i=B074J5699N&pd_rd_r=PN2829Q882ZHATN9Q1J3&pd_rd_w=RXkkm&pd_rd_wg=HcI8E&psc=1&refRID=PN2829Q882ZHATN9Q1J3

https://www.amazon.com/Preen-Organic-Vegetable-Garden-Preventer/dp/B000BQONLA/ref=pd_sim_86_3?_encoding=UTF8&pd_rd_i=B000BQONLA&pd_rd_r=7QQYRXJGBTDC4DE38Q07&pd_rd_w=WYJ97&pd_rd_wg=RWSuj&psc=1&refRID=7QQYRXJGBTDC4DE38Q07

As long as you don't get any on the flowers, you can use boiling water. You can also lay down layers of newspaper, then cover with mulch. That works also.

Buy some cheap small foam paint brushes, rubber gloves, and any weed killer. Pour some weed killer in an old jar, plastic cup or whatever you have around. Dip your sponge brush in the weed killer and ring out so it’s not dripping then just lightly brush the weeds you wish to kill being careful not to brush your flowers. If you accidentally get weed killer on your flowers, just give your garden a really good soaking right away to dilute the weed killer. Wait a few days for your garden to dry then try again. I’ve done this in several of my beds before I mulched them. It‘s kind of a tedious chore, but if you mulch after your weeds are brown then you’ll find you won’t have too much of a weed issue come next summer.

I pull or dig my weeds, then put down Preen Weed Preventer. It works on all weeds that come from seed. Once I do this, all I have to do is take care of tree seeds and root born weeds like some grasses and Creeping Charlie. Those I catch as they show up on the edge of the garden.

Boiling water poured over the roots will kill the weeds. Then cover with landscape fabric and mulch to prevent them from coming back

Ortho Grass B Gone works pretty well and is safe for most flowers. Read the label.