Originally Posted by kay

There's no difference between weeds and flowers - a weed is merely a flower growing somewhere where you don't want it. So while there are persistent weedkillers, they will stop anything else growing. OK for paths, but keep them well away from flower beds and lawns.

Or did you mean you have some persistent weeds which grow back even though you think you've pulled them out? In which case try something containing glyphosate - it's a systemic, which means it is taken into the plants system, and kills the whole plant "from inside out". Takes about 3 weeks for a visible effect. Don't let spray drift on to anything you don't want killed and keep it well away from your lawn.

The best deterrent for weeds is a bigger and stronger plant! If you plant your flower beds densely, then weeds won't be able to compete (and the few that get through won't be very visible amongst all the other vegetation).

Originally Posted by echinosum

Where is weeds a problem? In flower beds, you can apply the "stale bed" approach. A lot of weeds are annual weeds, and grow from the accumulated load of dormant seeds in the soil. But if you weed regularly, and don't disturb the soil, then the number of new weeds growing eventualy reduces, not to nothing, but to rather less. For perennial weeds, you have to make sure you pull the full root out. A dense covering of shrubs helps exclude weeds.

Weed-proof fabric helps. I lay this over the vegetable bed during the winter, and it greatly reduces the labour when it comes to replanting it in the spring. I have a patch of land permently covered in weed fabric, with a covering of decorative gravel. But weeds still succeed in growing in the gravel... But at least it is a lot less.

There are chemicals that can be sprayed on paths and driveways. Pathclear kills off teh top growth, but perennial weeds grow back from the roots. You need glyphosate to kill off perennial weeds. Though some of those seem to be resistant!