Two years old or not... I always like to chime in on these watering discussions to caution new people: ERROR ON THE SIDE OF OVER WATERING! Unless you just absolutely DROWN your tree to death (this is hard to do for most), the most common side effect of over watering is more rapid growth. The most common/ unavoidable side effect to a tree that does not get enough water is DEATH. INSTANT, IRREVERSIBLE DEATH. So, decide for yourself. Do you want a tree that is a little shaggy and needs a hair cut a little more often, or do you want a DEAD tree?
This is my recurring public service announcement and especially relevant amid this brutal heat wave we are suffering through in my area currently.
Here is where I get long in the tooth, so skip all this crap if you already got the point!
Opt for free draining soil, and water OFTEN. More often than you think you should need to... If the soil is free draining, it is difficult to over water! Water thoroughly.. Watering is not just about getting the roots wet, it is about air exchange and vacating old, "stale" air from the soil by flushing the soil completely with water. So, water til it is running out the bottom of the pot (what's that? No holes in your pot? FAIL- get a new pot NOW or drill some damn holes in it!!), wait a minute and water again... Rot occurs from stagnant/stale air allowing bacteria and all those nasties to grow in a stagnant environment without consistent flushing and replacing the air. Daily watering is not necessary when the trees are dormant- colder temps and the much reduced water uptake from roots means they simply don't need much water.
Heat and WIND combined are killers. I had an Elm shrivel up on me last week that had been watered at around 6:00 AM by my sprinklers... I got home for lunch around noon (always do some watering on my lunch break) and it was a complete crispy critter already- been soaking in a tray of water ever since, hoping it will come back... Not looking so good so far! This time of year- EVERY TREE gets water EVERY DAY- usually 2-3 times a day for most. Regardless of species, potting mix they are in, location (sun/ shade...) 100+ temps just fry them right up if they aren't kept at least moist... Some have to literally be kept in trays of water. Root rot has never been an issue for any of my trees and I have watered on This type of schedule for... At least three years now! Prior to moving to this, I lost multiple trees every summer and I finally realized I was trying to "keep from watering on a schedule/ avoid OVER watering"... It was tree murder. I had a misting sprinkler system that would get stuff kind of wet on a schedule for me, but it just gave me a false sense of security that my trees were watered enough when they weren't! No substitute for a watering wand/ can and hitting every tree yourself by hand every day.