Any suggestions what to plant in empty spot?
 

We had a small yellow tree there, but it didn't make it.

Golf balls spilling out of flower pot.

Need more info.

What direction does wall face?
What type and pH are the 1' of soil below the mulch?
Is there irrigation? What type head hits it? How often and how much water is going on that spot?
What are your parameters for flowers and maintenance?
Do you like color (variegated) leaves?
Looking for something taller? Medium and bushy? or ground cover height?

I'll stop here. Should allow me to narrow down the thousands of choices to a few or even 1.

Take the snake plant out of the pot and plant it. Free up a little space.
It will do fine year round in that protected spot

Or replant one of the other low bushes pictured there. Move the snake plant in That spot. You’ve got a lot going on…I wouldn’t add anything…just rearrange.