Hi gardeners,
I am a completely newbie with gardening but I am eager to learn and try new things. I also do have the time and the physical ability to spend some time on this. I recently moved to a new development in the suburbs of Seattle (Zone 8b) and would love to plant a border or at least a few plants in my otherwise sad little bare yard. I dug under the beauty bark by the retaining wall and found that less than 4 inches down, I hit dense sand. I think the builders dug up the existing area (which used to be wooded), and leveled the foundation area with sand. About six inches further down, there are sizeable pebbles and rocks as well as the sand. My question is, what are my options for planting along this retaining wall? I've been watching YouTube videos and I love the look of English gardens. I'm thinking plants like creeping phlox and other rocky soil/hardy plants along the top of the retaining wall, and hydrangeas, hostas, snapdragons, and other perennials in front of the wall behind the bird bath. I get about six to seven hours of sunlight right now along that retaining wall area. I assume that having someone come in to dig a deep trench along the retaining wall and refill with soil would cost a fortune. Perhaps I can do it myself? Are raised garden beds (I'm thinking something like the Vego) my only option here?

Thank you in advance for any advice!

Photo of the sand 4-6 inches down.

All the plants you mentioned can be planted in a raised garden bed. Adding 3-4" of good garden soil will give all your new plantings a good start.
Wonder why sand is under the there?
Weather the native soil is sand or clay raised beds is a good way to go.

Thank you, @bumplbea ! My wish was to be able to plant directly into the ground but I guess a raised bed isn't bad either.

I would plant some vining plants in a few spots along the top the retaining wall for vertical interest. Even annual vines. Then I would put coneflowers up there for some shorter height and creeping phlox would look good every few feet. Tall sedums would do good and creeping sedums would love growing in the crevices. Since you're in Seattle you might look into moss growing also.

As far as improving the sand, add a mix of topsoil and compost in there every year. Don't go deep, just use a trowel or shovel and that will be a good start.

For in front of the retaining wall, my above suggestions work also and pretty much anything that catches your eye at the nursery. There are lots of plants that will work. I personally love zinnas and think they would look good there against the wall.

Sorry, if the post seems a bit scrambled. Was jumping back and forth between typing and your post trying to catch everything.

Yeah, like that ^^^. You could start with plants that do well in sand: salvia, lavender, sage - the Russian kind is pretty - rosemary, butterfly bush, black-eyed Susan .... Several of these will grow into nice big bushes. You can still improve the soil to accommodate more kinds of plants, just don't make it too rich.

I'd imagine the sand was used to set the rocks... Rather than being used to level anything.
If you want to see what they used to level the soil with, you'd have to lift some of that sod.

When you say that you want to plant along the wall... Do you mean that narrow strip between the turf and the rocks? or... were you planing to make a decent sized bed by taking up a bunch of the turf?

by how green the grass looks, I'd say that you would stand a good chance of growing anything you wanted once you cleared some ground.

I can't imagine digging a trench and removing soil and then bringing other soil in...
I've never had to do more than take up the grass and shovel turn the soil beneath... Ideally, I find a source of manure / compost to turn in with the existing soil... And... plant, mulch, enjoy.

No idea what the sand is about, it could be lots of things, maybe the builder just needed a place to unload it so filled that in to get it off his hands. Maybe it is there for drainage? If you get alot of soggy soil there pushing the fence/rock it may be a problem? Also, have you talked to the neighbors to see if their homes are the same? And have you tried to contact the builder/landscaper? If there isn't any reason to keep the sand, dig it out a little at a time and replace it. Plants you put there may need fertilizer more often as sand is of course lacking in nutrients. I'm just thinking if does have some NEED to be there, of course you will need a plan B and can cause a huge problem if you take it out, so ask around and be certain before messing with it.

Not sure what you can grow where you are, but I'd put an assortment of evergreens on the top, and trellis w clematis. Then plant a ground cover like creeping phlox or ajuga or lamium ect.
Then I'd plant flowers along the front of the wall, and bump the mulch out.

That design looks pretty, but I don't think there is any soil on top of those rocks. The evergreens would have to go in containers. Not a bad idea; vegetables and flowers could go up there in boxes, too. The strip in front of the rocks would do nicely for herbs and poor-soil plants. Alternatively, dig individual holes and flowerpots - each with their customized soil.

Oh< I apologize, I think I misunderstood? I though the sand was between the fence and the rock retaining wall
well disregard my ideas lol, they are dumb

Frillylily said: Oh< I apologize, I think I misunderstood? I though the sand was between the fence and the rock retaining wall
well disregard my ideas lol, they are dumb

But you made such a pretty mock-up! And it's a good idea to put some plants - I agree about the conifers, too - there. Say, in cedar boxes. Wouldn't that look elegant?

Wow, everyone! I didn't get any notifications about this post but thought I'd visit it again just to see. I wasn't expecting so many kind responses so thank you! I love the mockup, @Frillylily . :D And @pepper23 and @Serpent , thank you very much for the plant recs. I'll have to see what's available at the adorable nursery nearby but I'll bring this list.

As for the soil/substrate, the developers aren't getting back to me about it (it's amazing how quickly they'll ghost you as soon as they have their money, haha!) but it's basically dense sand and rocks right under the beauty bark. The grass was recently laid down so I haven't pried it up to see what's underneath but I suspect it's sand or a very thin layer of soil over the sand. I do have some rocky soil to work with along the top of the retaining wall (before the wooden fence) and my neighbor has planted ferns and what looks like Japanese andromeda along that section. As for the area right in front of the stones, I'll most likely have to do container planting in addition to a narrow raised bed, though something like Frillylily's beautiful layout would've been ideal. Thank you again for all of the suggestions. I'll talk to my neighbor to see what their situation is like, and will do more research before I potentially damage the area in front of the retaining wall.

You're going to have to feed that grass, too, if there's nothing nourishing underneath. Might consider whether you need a lawn, or it could (eventually; I know you have your hands full just now) be replaced, or supplemented, by an undemanding groundcover.
https://www.missouribotanicalg...
https://www.missouribotanicalg...
Just something to keep in mind.
Oh. I just remembered. If you're going to plant something directly into the ground by the fence, better put some kind of barrier, so it doesn't creep into your neighbour's yard - or vice versa - unless you both agree that's it's okay.

I think you did a really nice job for a beginner! I am a newbie as well.. However, I did learn a lot from a group of Essex garden designers called consiliumhortus.co.uk at their blog page, plus my family is a friend of theirs so I got some firsthand advice!

@Serpent thank you for the lawn alternative suggestions. I do want to replace the grass with something like a stone pathway and plants, but I'm pretty sure our HOA would be against that if they were to ever find out. I love the look of stonecrops and I just planted (stuffed) a few in the rocky crevices of the retaining wall so we'll see if they take root. I'll look into some environmentally-friendly grass fertilizer. I hear you can make your own with beer, baby shampoo, etc.!

With all of your suggestions, I started playing around with some ideas and came up with this layout so far. There is soil on top of the retaining wall, so I could probably work in some compost or something and plant coneflowers, black-eyed susans, lavender, sages, and creeping phlox, and possibly orange honeysuckle. For the area right in front of the retaining wall, because the soil is sand/poor there and I don't want to mess with the foundation of the wall, I can container plant in that area, and I have a raised garden bed coming where I can grow some flowers, herbs, and tomatoes. Using trellises or a fence-mounted plant pot for some vining plants might be fun too. I'll definitely make sure the areas next to my neighbors are blocked off so the plants don't go creeping into their yards.

You can also plant in the crevices of the wall. Perennial herbs love growing there, creeping sedums, basically anything that likes dry and cascade or creep will look great. Just stuff a plant in a crevice, tuck dirt around em, water em and watch them grow. That will soften the wall up some along with the normal plantings.

Excellent ideas. I especially like the trellis - morning glory? Sweet pea? Could be great. A quick suggestion about containers to plant in. I don't know whether cost is a consideration for you, but if it is, think outside the box. Lots of things can be planters that were not sold in a garden supply store - use your imagination, yard sales and thrift stores.
I would love to see the results. But that's months away. Could you let us know by starting a new thread when you're ready to share?

I like Frillylillys idea better than yours op. A few evergreens will provide structure and are a good starting point for any garden. Put the flowering stuff in between. They also provide winter interest when everything else is gone. Placing them is critical, they anchor the whole garden. Rhodies and azaleas provide flowers and are evergreen.

I don't know what the soil there is, or if the area is wide enough (although selecting the right shrubs is key as some evergreens stay narrow). I was just looking at the photo for what it was, but it may not work.

There are some ever greens that do stay quite narrow and get all, such as Green Tower boxwood, or sky pencil holly, I am sure there are others too.