Congrats on your new house!

These questions are impossible to answer without knowing what weeds you have (had) and more about the weeding that was done. Was everything pulled out with all of its' roots? Were these seed-dropping plants? What state are you in?

Dirt in the mulch is fine but it's understandable if it's unsightly. Do you know what kind of tree you had removed/shredded? Just make sure whatever you cover it with is not some toxic, painted garbage. If the shredded tree mulch is in pieces that are mostly much thicker than your finger, it may be far less effective than something more finely shredded in regard to weed suppression, and certainly less beneficial as a soil improver since it will take an extremely long time to decompose, will not help moderate moisture levels as well, and could cause nitrogen issues for the plants in that bed for the first year or two.

The tree that was mulched was a cottonwood.

As for weeds, ahh so many dandelion, thistle, broadleaf plaintain, mallow, creeping jenny, wild onion, and a few others. We are in Denver. We dug/ weeded out as much of the roots bulbs (onion) as possible, however I had my teens helping so....

I have to disagree a bit with purple. What you have done is exactly what I would recommend. Tree chippings are the BEST weed suppression you can get. I use a thick layer on our acre of property, and have very few weeds. We go through about 40 yards of chip a year (delivered free), and the plants love it. You won't have problems with nitrogen deficiency unless you till it in, but if you are concerned, put a slow-release fertilizer such as osmocote or a slow-release organic fertilizer around the plants. Over time it will break down into beautiful worm-filled soil. You will learn to appreciate it over time, but you can topdress with nicer mulch if you wish. I would hit any bulbs that pop back with a systemic herbicide. Try to get any weeds out before they go to seed if you can. If you are not overhead watering, weeds should not be a big issue until the fall. Preen would be most effective in August, just before the fall rains, but I'm betting you won't need it with a thick mulch layer (call the tree companies for more!)

Any "weed" seeds that may be in the soil under that 3 to 4 inch layer of mulch will not get the sunlight they need to grow even of they germinate so they will die. However, new "weed" seeds can, and will, germinate in that mulch. Those will be quite easy to pull out since the roots will not be hanging on to the soil for dear life. Also, some few "weeds", such as thistle, could grow and push up threw that mulch and those are not easily dispatched.

Sorry, I didn't mean to imply that anything incorrect had been done, especially since I wasn't thinking that. It sounds like gmp & crew did what they could, and I fully support the use of the chipped tree as mulch but just wouldn't be confident in its' performance without supplementing it with a layer of finely shredded wood or even chopped leaves this year, and maybe next, until the larger chips of wood get to a more rapidly decomposing state.

Larger chips have larger gaps that make it easier for seeds that sprout on top to get their roots into the soil. Finely shredded makes a more solid layer, especially at 3-4" deep.

I had the same thought as Kim about the thistle, you may see some that are able to pop up out of the mulch. Try to get the whole root if you see any.

Cottonwood is good, just wanted to make sure it didn't happen to be a black walnut.

Thanks everyone, there are some very large hunks of mulch, but most of it is shredded and very thick so it sounds like I am on the right track. Luckily the thistle was minimal, but I will keep after it as much as possible this summer.