I mulch leaves right back into the soil... it's free fertilizer, I only wish I had more trees on the property. Pine needles on the other hand I can't mulch up, the tractor will just keep blowing them out. I have a bagger for my tractor that I use to clean these up with. The only problem is that there is always so many that I'll have to empty the bags a good 20 times. This is actually the worst I've ever seen it. I'll gather some up and spread them around the base of some of the plants for added winter protection and mulch. I'm not going to add as much as I was going to because I just found out they blow around easily. Well at least they do today with winds around 30MPH. It's actually a lot worse right now, the entire picture above is tan, hardly any grass poking through. The winds are increasing, blowing them further

You don't need the cardboard unless you are trying to kill green, growing plants. Just use the mulch. The roots will grow up into the mulch after a few years.

that is the flare .. where it changes from trunk to roots ... trunks are made for air.. basically always dry ... roots are made for soil ... and often damp ... it actually looks like deep mulch.. which is fine.. but NOT on the trunk ... so pull it all back.. about a foot around ... maybe sprinkle a bit back over that.. no more than a half inch or so ... we have seen trees planted up to a foot below grade at the root flare ... and then a year or two donw the line... the bark starts failing.. and trouble hits ... etc ... i think you are all set .. ken at a look at this link ... and the 5 th link in particular ... just insure.. over the years.. that the mulch dudes just dont keep mounding it.... AT/ON THE TREE ... https://www.google.com/search?q=mulch+volcano&source=lnms&tbm=isch&sa=X&ei=c3pwVd-qNcTnsAWZxoDYAQ&ved=0CAgQ_AUoAg&biw=856&bih=745&dpr=0.9

Here is what mirabilis (4 o clocks) look like with Mystic Beauty. Blooms are show and last until fall. Self sowing, but easy to recognize and pull out. I originally got this two years ago because it was supposed to be poisonous to Japanese beetles, but the it blooms after the JB peak. I notice that JBs have become less of a problem especially this year but I am not sure if that is more due to my vigilant picking them every morning for two years in a row. I also have a yellow mirabilis but it has not bloomed yet.