kia ora class,
As mentioned today the concept plan is the 'sales pitch' version of your design. Is needs to be refined to a level where the audience gets a real sense of the planting textures and qualities of spaces that your design will create.
Here's the Freeland Reserve concept design package, the plan on page 14 and the plant palette on pg 12 will give you some guidance on the level of detail to provide and how to represent your design.
Another example is Kopupaka Reserve https://ourauckland.aucklandcouncil.govt.nz/news/2018/12/concept-approved-for-6-million-kopupaka-reserve/
If you are stuck on planting palette composition, don't forget to check NZPCN or Auckland Council for typical planting combinations:
https://www.nzpcn.org.nz/ecosystems/plant-communities/
Ngaa mihi
Heather