Hi Michael and welcome to the Disney Parks Moms Panel.
You are going to blown away by all of the beautiful topiaries and other brilliant blooms on display at the
Epcot International Flower & Garden Festival.
At this moment in time, it is not possible to link reservations for Special Experiences and Tours on My Disney Experience.
When I have experienced this situation myself in the past, I simply added the information manually in the "Notes" for the day of my reservation. To do this, you will need to log into your My Disney Experience account, go to "My Itinerary", and then select the day of your reservation for the
Gardens of the World tour. Then click on the "+" sign that says "Add Plans". You can enter all of the information here so that it's handy for you to access from within your schedule.
So long as you have a note of your reservation number, you are good to go.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma