Hello. I have a project that has no landscape consultant, so the architects are asking for assistance in choosing plants that will help us meet the 30% to 50% outdoor water reduction.

Our project is in Metro Manila, Philippines. I required them to use drip irrigation and recommended plants with low water requirement. Though I was only able to list down recommended plants based on my company's previous certified projects,  which had their plant profile forms filled in by landscape specialists.

Beyond my recommendations, I asked the architects if they had any other local/native plants in mind, to fit their concept.

My question is: How do landscape specialists determine the water requirement of plants? Do you guys know any website or source to know the water requirement of plants? To be exact, from the Philippines, South East Asia (or any site with international data will do). I am no landscape architect/consultant/specialist, which is why I ask this, for help and also out of curiosity too.

Thanks so much in advance! Hope all is safe and doing well amidst the corona virus outbreak.