Well, my two cents would also include obedience school and Logan has the right of it -- one at a time. However, there are other things to look at. What do you feed these two? Look at the ingredients of the food and if you find corn in the first three, look for another food with no corn in it. A good chicken and rice or lamb and rice diet should help some. Make the transition over the course of a few days, if you decide to change their food. Corn is a complex carbohydrate that can make active animals "hot" -- so full of energy they don't know what to do with themselves and generally end up being unintentionally destructive because of all the extra energy.

How old are these "children"? The cocker should be maturing some at age one (give or take a few months) and the lab/staffie around age two. Are they teething? Do you have crates for them -- separate crates? Do you ever work with them individually on-leash? Do they even know their names?

Even though it sounds like you have a fenced back yard, you might consider installing a tie-out for a temporary measure and let them out singly for potty sessions. It should be situated so they cannot reach the plants you want to save and yet handy enough so you can get hold of the line to "draw" them in as you call for whoever is out. That way, they learn that the yard is not to be "eaten" and that when you say "Come" (only one command, please), you mean come now. As you reel the dog in on the line, give lots of praise along the lines of "Good come," "what a good dog to come," etc.

You might also consider a smaller fenced area that they can play in freely. Something like a couple of exercise pens hooked together or a good sized dog run. Then, you can put them in the fenced area to blow off steam and get out some of that energy, but not destroy the yard.

Inside, I would have separate crates and occasional time-out time. They should do better in airline types as that will give them the old "den" feeling. It is also a good way to housebreak if the crate fits right. This way, you also have the option of working with each dog separately while the other is in the crate and they should begin to listen to you more. Try teaching each of them tricks -- shake, sit pretty, rollover, etc. Use treats and that should help get their attention on you and what you are saying.

I also agree that the squirt bottle can be a help, but is difficult to catch both of them if they're racing across the yard and such like. How about a hose? Can you squirt them with the hose when they are being naughty in the yard? Anything that will suggest that being at a distance from you will not allow impunity from some sort of discipline while not necessarily implicating you as the disciplinarian. Not that that is bad, but sometimes they need to think that being naughty has consequences from other sources. Then, you can use the squirt bottle for the house. Shake cans sometimes have a good effect as well. It is something like a coke can with a few pennies or rocks inside that really rattle when shaken. The principle is to distract the dogs from whatever they are up to they shouldn't be and allows you to divert their attention to their toys/chewies.

Sure hope some of this helps. Let us know.