WASH the ROCKS FIRST!!! I do not use rocks as a mulch, but I do have a dry stream bed and another area with decorative rocks. I use a heavy amount of newspaper and then a double-layer of the good weed barrier. My stream bed is made up of all pebbles that I have dug up during gardening (I live on Long Island - a "boulder" here is anything bigger than a foot; a "rock" is anything the size of a fist; we mostly have beach pebbles). I literally wash all the dirt off my rocks before putting them in the stream. The rocks you buy in bags MUST BE WASHED as well!!! I bought some pretty rocks for a walk-about around a planter, and I realized that there was so much rock dust in the bag that weeds were bound to grow in it, so they had to be washed first. Here's my rock-washing technique (using pots with holes doesn't work - all the dirt collects in the bottom): I have a 2ftx4ft garden cart that is made of a steel mesh, so it drains. I cut a piece of window screen to fit it, then dump a layer of rocks on top and use a sprayer hose to power wash them. Note: Eventually weeds will grow down into both newspaper and weed barrier. Heavy newspaper will last a few years though. Weeds grow in cedar mulch as well, but they are easy to pull. Be careful with newspaper/ weed barrier if you have groundcover bulbs - they will eventually push their way up and it looks really bad. Also, if you have shrubs, do not put the newspaper too close - the newspaper will block any fertilizer you apply. DO NOT use impermeable plastics as a weed barrier - you will kill your plants, create puddles, and DESTROY the beneficial soil microorganisms. Plus, when you lift up the plastic (even after a few weeks) it will REEK like a landfill (due to anaerobic decomposition). Newspaper smothers weeds below ground, but I have just discovered that even doubled-up weed barrier does not stop small weeds from rooting into the ground. I have a small berm that I am trying to create a moss garden on with chunks of recycled concrete, and my moss keeps being invaded by grass, so I laid down a thick layer of weed barrier on the berm last year, then put in the concrete chunks, hoping that would stop weeds. Well, this spring I found a baby Maple seedling that rooted itself through 2-3 layers of weed barrier into the soil beneath. Now I have to remove all the concrete and smother the area with newspaper, then weed barier (seems to be ok for grass weeds), and then I'll probably put down a layer of sand-clay mixture that will harden into cement before the concrete chunks are put back. There is nothing worse than removing weeds from moss - the moss gets pulled up with the weeds. Even though I washed the rocks for my stream, I cannot keep all the dirt out because leaves fall from the trees and then decompose into dirt. So, if I start getting weeds there I will try either the vinegar or salt-solution remedy (my mother sprays ammonia on weeds that pop up between the bricks along the driveway). All the plants along my stream are at least one foot away from the edge, so hopefully I won't kill them.

With our heavy rains that parts of the US have been having after the rain slows go out and check your plants to see if they are still planted. Look around the area to see if you can find them if they have washed away. You can hold over night or so in a dampened paper towel. Then try to raise the sides of the bed an inch or so pr use rocks to suround your bed until the plants take root. Store bought compost can be used to raise the edges if you go this route. Once the plants are settled in and extend their roots into the ground you should not have a problem with them washing.

I have very wet clay soil, on a sloping lot, not good for growing iris. I only grow iris at the top of the lot in softly mounded raised beds. The grass desperately wants to invade these "improved" places. I use rubber edging around the main beds or edging trenches, straight edge of the outside rim down as low as you can go, slant edge on the inside, at least 5 inches wide. In addition, I use newspaper, lots of newspaper, covered by mulch, on the inside of the bed edges. In zone 5 the paper 8 - 10 sheets thick is good for a whole season. The paper eventually turns into mulch, & I repeat the process. Grass doesn't usually grow through this unless you leave gaps. It is relatively easy to do & doesn't involve any poisons. Cardboard boxes also work but are harder to cut/shape to the bed. I just save up the papers in early spring, and do any areas that I had problems with the past season.

Best way--and hardest work--is to just keep pulling the bermuda grass out. Water well, then start pulling when the soil firms and water has soaked in a bit. There are a number of herbicides that target grasses, however few of them have labels for flower beds. In some cases, the grass herbicides will also have some activity against certain broadleaves, so if you go off-label and just try something, you might get a few of your flowers as well. You might look at Preen in a small area as it is recommended for grasses, but don't know what it may do to the plants you want.