I agree with Christopher C Nc about letting plants grow and moving rocks. While you wait for the plants to grow, add some annuals for color or a low grassy textured groundcover.

If you stagger the spacing of your Vitalis, say bring every other one forward to form a triangle, it will fill in those bare areas you are seeing and give them more room to fill in. You could bring your larger ones to the middle so they show up more. Same with the rocks, get rid of that all in a row look as you wouldn't see that in nature either, just tweak a little so one is more in front and other two are slightly set back. A creeping sedum (or other creeper) in your front row would look great and spill over the edging but only do three plants as opposed to filling in every available spot. A good mulch would neaten this all up, cocoa bean maybe, something in the more brown family seems more natural to me than the orangey red ones but just a personal choice. Love the mock orange!

@Christopher CNC The rocks have not been placed yet, and part of the exercise was to figure out a good place for them. I disagree that rocks always look pointless. When well placed they add to the sense of a natural landscape and they are the objects you ordinarily find with plants in nature. If the rock is beautiful and has some shape or design, it is a piece of art on its own.

@D_M Do you have any specific suggestions?

@hu818472722 Good suggestions. I like the zigzag concept for the Vitalis. I think as those mature I may need to move them around as well but zigzag now will look more natural than lining them up like a corn crop.

Do you have any ideas for a specific sedum, maybe one that is a dark red or purple to give the whole thing some color?

I have never heard of cocoa bean mulch before. I will look at that. Maybe a desert stone on top of compost would work too?

Regarding the rocks; bury them at least a third or more of their height. Vary the amount buried between the three rocks.

You'll need to check for your zone. I like dianthus for a ground cover. Some have a thin leaf and flowers in various colors. Some are evergreen. Not all are short enough. Mondo grass is short and grassy. Go to a good nursery and see what they have.

@D_M I am glad to learn about Mondo grass. That would make an amazing filler between concrete pavers in a partio.

Rocks are wonderful in the landscape! I use them in my designs all the time - the ultimate in low maintenance gardening :-)

But siting them correctly so they look as natural as possible can be a bit of an art - that is all that Christopher meant. A defined semicircle following the bedline and spaced equidistant from each other is not a look you should be shooting for and I'm glad to hear that's not their permanent home! The other issue is they are all of the same approximate shape and size.

I generally prefer rocks of that size used in clusters rather than placed individually. More visual impact and you can nestle plants around them easier.

I'd also give consideration to the previous advice to stagger the senecio planting. Even with the curved front bedline, the layout is a bit too linear and regimented.

@gardengal48 Do you have any thoughts on selection of something like a purple/red sedum as ground cover for the area in front of the Microphylla?

How much sun does the area get? IME red leaved sedums need full-on all day sun to develop that red coloring. And even that's no guarantee it will look the same all year round.

@westes Zone 9b California SF Bay I meant no disrespect to the rocks. I like rocks. I do all kinds of things with rocks in the garden. I have rocks in my house. I have rocks in lines and boxes. All kind rocks.

A hardy drought tolerant variety of sedum spurium is called Dragon's Blood, grows 3-5", spreads quickly and good up to zone 9. Another variety is called red carpet which is smaller up to 1 inch tall so more like a groundcover. The nice thing about sedums is they are easy to grow. Head to the nursery and browse, so many lovely ones to choose from, blue-grey, lime green, bi-color leaves etc. it's hard to choose. I did read cocoa bean mulch could be harmful to small kids and pets b/c it smells like chocolate, so maybe not the best choice but ask what works best for your region. Your larger rocks can go on top of mulch, they may look better on top of smaller rocks but then gardening around the smaller rocks is a huge pain.

@gardengal48 During the Summer that location gets full sun. During Winter full shade.... Maybe Sedum is the wrong plant for that location since many of those shed all leaves for the Winter. Is there any kind of red succulent groundcover that would stay visually attractive year round?

You could try a Heuchera (Cherry Truffles) which is reputed to keep it's leaves in warmer climates, Red Sedge Grass variety Fire dance, Red Salvia, Aloe Vera, Agave, or Yucca plants are all good drought tolerant options. If you look at the picture of the Vitalis you provided above there are both grasses and aloe plants next to it that look very nice, your contrast plant does not necessarily have to be a red color it just has to harmonize with the plants you are pairing it with.

@hu818472722 Cherry Truffles is a nice-looking plant, but that would be too dominant and would compete against the Microphylla. I think what the design needs is a low-to-the-ground plant with a little color. Sedum would work, but now that I think about it more many sedums die off in Winter and that is not desirable here.