well ... moist is NOT sodden ... wait.. that not on your list.. lol ... roots need air.l. as much as water ... and if you water so much.. that you remove all air.. they will drown ....

lets start with your soil type ... clay and sand are opposites with drainage ... and everything else is beautiful.. and in between ...

i would suggest .. you dig 3 to 6 inch holes.. with a hand trowel .. around your plant ... and when its drying at 3 inches .... its time to wet it deep again .. make it MOIST ... lol ..... see where you finger wont work ...??

we need to keep moist.. that whole root ball you planted ... until the plant can put its roots. where it can take care of itself..this is usually accomplished in one or two years... and i would only worry about a hard drought in year 3 ....

defining how it all works in your soil.. in your garden.. simply can not be answered.. with any certainty.. except by you.. and your hand trowel ...

it probably.. wont take you long to intuit it all.. after a few weeks of those small holes ... it will all become rather predictable .... but one thing for sure.. they can look bone freakin dry on the top two inches.. and simply have enough moisture at depth ....

its what i had to do.. when i laid down drip irrigation for my hosta beds.. no one could ever give me a good answer.. so i had to resort to digging holes ....

so get to it ... [there was an old seinfeld.. where there we peeps who dug in central park at night;.. that cracked me up ...]

whatever you do... they can not stand in water in bad clay.. they are trees.. not bog plants ... advise if those are your circumstances [i presume.. on some level you think i recall your whole project.. i recall the name.. and i recall i like helping you .... but i dont recall the project specifics ]

go dig some holes.. and report back.. what you find ....

ken

ps: when deep watering.. once you are sure there is deep moisture... i would not be surprised.. if you should need to be watering more than once every other week or three ... with a good mulch ... subject, of course.. to intense heat.. drought.. ambient rain.. etc ....

Matt, are you moving the bucket around as it drains so that the entire root system is getting the water?

One thing you could try is making declivities to support the neck of two liter cold drink bottles. Cut the bottoms off of each of them, leave the cap in place, but loosened so the water can slowly seep out. OR alternatively you could puncture the upper part of the containers with a heated pointed thingie - think small awl or ice pick.

My understanding is that the soil moisture should be checked at a depth of about 2".