Estate developer enforcing Landscaping guidelines

Hi all
I have built a house in The Platform estate in Donnybrook VIC. Its a rental so for the front yard I just put paving, timber edging and Tuscan toppings.
Now the developer has come back saying that the landscaping has to be done according to the landscaping plans that was submitted by the builder which included planting along with lawn.
In the email they have threatened legal action if the landscaping is not done as per the submitted plan within 30 days.
The email also states that this will cause problems when I try to sell the house.
I found this to be a bit extreme.
How much of this is true? Has anyone been in a similar situation?
Any feedback will be appreciated. Cheers.

Same boat as you are

It seems a bit unreasonable in my opinion for an investment property.
I had plants & grass installed and all dried up because the tenants didn't look after it. Hence I filled it with Tuscan toppings.
Can't seem to win here with this developer.

estate design requirements aren't different for owner occ or investment. They're trying to achieve a unified look. Install some automatic reticulation so that tenants dont have to think about it.