Q.Where to get soil analysis
I have a a curbside city planted tree to which I wanted to add some annual flowers and other plants.
I’d like to amend the soil and need to know what minerals to get.
Where might I send a dirt sample for analysis?
Certified GKH Gardening Expert
Your local extension center should provide those. Here is the link to find the extension center near you.
You also can buy kits for soil analysis you do yourself.
Commercial soil testers would be listed online or in phone listings.
I will tell you however that it is best not to plant under trees. You can disturb their surface roots. It's best just to put mulch out to the dripline.
Here is information on planting carefully under trees to do the least damage: