Question: will the cedar trees block the sun from that lower bed? In other words, will it be a sun or a shade garden?

Also, what do you mean by Cedar? That name is used for a variety of conifers by some people.

Location?

I've looked at apps. The thing you have to watch out for is scale. While plenty will prevent you from making your tulips bigger than your oak trees, most will not scale things well. Most are a good 25% or more off scale. So, you get a great picture, but when you go to implement your plan, you have puny plants or ginormous plants and it doesn't look at all like the plan.

Needless to say, this is why I can't recommend one.

if you want to talk plants.. we need to know where you or the garden are ... big city name ...

you can do all your brainstorming here ... no need for referrals to other sites..

use specific forums for specific plants.. many plants are called cedars... but all are conifers.. and/or trees... use those forums...

also use perennial.. annual..etc ...

there is a hosta forum.. but i suspect there might be too much sun for hosta.. but location will matter ...

find local labeled gardens.. and visit all high end nurseries.. to find out what grows near you.. and what is sold.. rather useless to dream about hings that wont grow in your yard.. or arent sold locally ...

you can mail order anything in.. dishonest sellers will send you anything you want... local peeps sell whats thrives in your area...

ken

Is there anything preventing the soil and rocks from touching the neighbouring wooden fence?