Ask Mr. Smarty Plants

First, we recommend that you read A Guide to Native Plant Gardening in our How-To Articles. Ordinarily, we recommend native soil for native plants; the point being that the native plants have grown in that soil and that environment for millions of years. We also often recommend mixing compost into new beds being planted, especially where there is clay soil. The compost improves drainage and help the tiny little rootlets access the nutrients in the soil.

We have no experience with mushroom compost, so we did some research, finding mostly opinions, and not sure which are solid facts. The first article we read was from Doug Green's simplegiftsfarm Mushroom Compost. Next, we would suggest Oregon State University Extension Mushroom Compost - Use Carefully. And, finally, Dave's Cave - Mushroom Compost. Frankly, by the time we were finished reading all these, we were not very much in favor of the concept. Some words kept popping up, like "salts," "heavy metals," "straw," "corn cobs" and "fresh manure." It probably wouldn't do any harm, but we think some nice healthy compost with live organisms to help break down the soil and make nutrients more available would be better, and possibly cheaper. Or you can make your own compost, but that takes a while. 

Since you didn't tell us what plants you purchased, we recommend that you use our Native Plant Database to look each one up in order to understand how much water, sun and space each needs. And don't wait long too get them planted, they all need to get out of those pots into some real dirt before it starts getting hot.