I would make sure your trees have a well around them so when you water, it won't run off. Try using adjustable emitters. that way you can turn them off when you need to. I buy my products from Ewing Irrigation, There is also Sprinkler World and Horizon Irrigation. They have better products than the box stores.

they have a basin now, that's how i water the mesquite. the ficus and the ash i just lay the hose on their drip lines and let the water trickle overnight once a week for each. being that they'll be on drip emitters now it's unlikely they'll need the basin anymore though. i was kinda hoping someone knew how many gallons each tree should receive and if they could receive it during the span of 60-90 minutes. if they need more water or need it to drip for longer than that then i'll have to setup a separate circuit just for them.

you should still keep a well around the trees. You need the water to soak down deep to get the roots to go down into the ground.

We soak our trees with enough water to fill the well around them. You may need to determine your water flow and time required to fill your tree wells.

Hi xill,

Here are approximate water amounts needed by your ficus, ash and mesquite based on information from the University of Arizona.

15 ft. diameter ficus - 300 gallons once every 10 days
10 ft. diameter ash - 120 gallons once every 10 days
new mesquite (guessing 3 ft. diameter) - about 5 gallons once a week

You'll just need to figure out how many and what size emitters are needed to apply this amount of water.

this is exactly what i was looking for. thank you. i couldn't find squat through google, but this is the reference i needed :)