Wow - you have a serious challenge here. I can see why you are perplexed as to how to handle it. I do love your description of the moat, though, very good way to explain it. I would guess that a lot of the moat stays shaded almost all day because of the shadows cast by the retaining wall and the fence. One big question is ... what do you want in that area? Do you need it for anything - like an area for the dog to run? If it was my moat & I was happy enough with the size of my backyard such that I didn't need to moat-area for any function ... I would do the following: Kill the stuff that is there. Either physically remove it to kill it, or use an herbicide (brush-be-gone) that kills down to the roots and then remove it. Ensure the ground that is there has decent drainage & pH. Then I'd add some compost (3-5") and mix it in. In any area that has enough sun, I'd plant some fruiting trees/bushes. Blueberries, pears, cherries, apricots ... whatever the soil can support & I like to eat (which is all of those except pears). I'd buy the world's best weedblock fabric (the cheap stuff is cheap for a reason) and use that plus a ton of barkmulch to minimize weeding/maintenance around my trees/bushes. In 3-8 years I'd stand on the retaining wall and pick fruit that is at eye level, instead of climbing a step-ladder. And I'd be patting myself on the back for how relatively easy it is to use bird netting to protect my crop, since I can reach the top of my trees much easier. Now if your HOA prohibits fruiting trees, then maybe you just use some "street trees" in the moat. I'm talking about trees that top out at 20-30', they'd keep a nice canopy at the right height (just above the fenceline) and give you some privacy in the summer. I'm not sure if redbud or red japanese maple or sandcherry would do well in your area. But I'd look for trees with color - either blooms or foliage - so they stand out. Good luck, and remember that this doesn't all have to be completed right away. It's perfectly normal to attack these kinds of projects in stages and have your plan evolve over time. Unless you are on HGTV, no one's yard looks great after just a few weekends of work :)

Kitasei, the rocks are not actually landscaping filler. They are river rock mulch (as opposed to wood mulch) on a prepared shrubbery bed, separated from the lawn by metal edging. It's extremely common in the Denver metro area. When properly planted, these rock mulched beds are quite beautiful. It's just a different look from that seen on the east coast. ColoradoLime, you haven't mentioned your elevation. From what I am reading about the Abies koreana 'Horstmann's Silberlocke', it's mature width is 10-12', which might fit in a corner of your bed, however, it's not recommended above 6000 ft. If you're at a higher elevation, you might take a look at some of the Juniperus scopulorum cultivars. There are a number of very slender (3-4' wide) choices. You could even do a grouping of 3 in a corner with a groundcover at the base. Denver Botanic Garden has 2 beds with 3 surrounded by perennials. Stunning! One observation I would like to share - our daughter and her family are in a new home in Castle Rock, with an almost identical backyard setting as yours. ALL of their adjoining back-fence neighbors have planted trees within 2 feet of their own fences. As a result, our daughter isn't planting any. They are surrounded by trees! It appears that yours is also a new development. Just something to be aware of. Some things to consider (keeping in mind your elevation): Evergreen shrub - dwarf pinyon pine Evergreen tree - Picea glauca 'Pendula' (weeping white spruce) - 20-24' tall x 3-4' wide. This would be striking in the corner and definitely something your neighbors are not likely to plant. Evergreen tree - Juniperus scopulorum 'Woodward' Deciduous shrub - 'Mini Man' dwarf Machurian viburnum (good for small beds) Deciduous shrub - Spirea - there a many cultivars that remain small enough for your space and have lots of color during the summer and the fall. Perennials - too many choices to even list. Perennial heaven here! Have fun!

Haul it away. No unless you have money to burn. BTW, you could burn some of the bigger twigs to make them take up less space, but wood ash is very alkaline so don't heap it all in one place and expect things to grow there. 2. Pay someone to grind it . . . hmm. It seems like what you have is not enough to make that a cost-effective option but you might investigate. I just saw an ad in my local paper for someone who offers tree trimming and shredding but you don't know if that is just more of the same level as what you have, so investigate. I get very woody debris from the power companies out at the Arb. and we are always picking out sticks from it, but we just throw them into the woods for the most part. Finding someone with a good mulcher might be difficult but you never know. I am toying with buying a small electric one just for twigs around my yard, but have heard they don't last long. 2, OK to leave as is for a year? I would think so. As far as needing more mulch, you can figure that out in a year, see what you've got. If it looks shabby you can pick out the big stuff and then freshen it up with a top dressing of fancier mulch if you like. Stuff that isn't breaking down, the big pieces, aren't robbing the soil of nitrogen. I don't know about the smaller stuff, it depends. If in doubt, test the soil before you plant the grass. I think you're supposed to test the soil anyway. Some people get a load of topsoil to rake around before they seed a lawn, depending on how good or bad the soil is. Seems like your money would be best spent on something like that rather than futzing with your mulch. But test first. I don't think you're ruining your soil leaving mulch on it for a month or so. But if it were me, I'd read up on seeding a lawn and check off all my boxes for that. If you want a lawn, focus on doing the lawn. I think you are wise to just rake the stuff into the area you want to have for shrubs and leaving it. It will be fine in a year and then you can decide what to do with that area and what's left. I find it best to break up a big re-landscaping project into sections and focus on getting one part done at a time. Take some time out to enjoy your yard too!

Talk to some landscape designers and ask to see their portfolios. I’ve looked at a lot of landscape photos online and most of them are overdone, loaded with too-wavy lines, unnecessarily complicated shapes, fire pits and fountains that no one uses, redundant “features” and stepping stone paths to nowhere. A good pro design will address your family’s needs in the simplest way possible, IMO, taking into consideration the amount of time you want to spend maintaining it. Making a list of your needs and wants and a sketch of your yard as suggested above is the first step. You can do it yourself if there are no grade change or drainage issues, or paver installations that you can’t manage or aren’t willing to learn how to do correctly, but it’s hard physical work and there’s a lot to learn first. Planting and mulching is moderately hard work but doable with some advice on plant selection from a good nursery or the forums. Books from the library or online advice on proper planting methods are important for success. Having a lawn seeded or sodded is not that expensive in my area. Lighting is a job for pros. Here is an outdoor living area with a patio for sitting/dining, grill, lawn, simple flower beds, and not-yet-mature plantings for privacy in the background. It provides a walk from driveway to house. Small tree for shade. Retaining wall provides an interesting grade change. Out of view is a bird bath for bird watching, and additional small sun and shade gardens. No squiggly lines, extraneous rocks and gravel, squirting fountains, monuments to stone-look blocks, or kitsch. Simple. Professionally designed. Last summer this area was a construction site with a new septic system being installed until the patio, sod, and new driveway and were installed around October. There is enough space here to satisfy an urge to garden but not so much that it creates a burdensome maintenance problem. Beds are kept mulched for weed control and moisture retention. You could easily do something like this in your yard even if you completed the project over time. Some of the garden accoutrements here have been collected over a 25 year period. Some of the gray pots on the ground are 3 or 6 dollar plastic pots from walmart painted with rustoleum camo color spray paint that blends in with the concrete and stone. They were lime green before. Good luck and try to enjoy the process.