Must design that in to a growth scenario. Get project management right, that every one does it the same way. Many will complain that they do not need to be involved and are getting spammed but all must understand what is going on in the organization. And the systems you put into place must be more efficient than before when you where a relatively smaller, simpler company. Sounds mutually exclusive doesn't it.
Hierarchy is a framework that the vine of trust grows on.
It does not substitute for trust. Communicate your mistakes as well as successes. Everyone will know eventually anyway. Make sure you point them out first and tell folks or involve them in the creation of the plan to correct it or not repeat it. Do not surprise folks.