nice job... what type of climate do you have, that your tree is so far along? My crepe myrtle is a bit slower... ok different form and shape, which requires more growth, but my shoots are not quite as long. and... which nozzles are you using for your automatic watering? I know.. off topic question...
so im in southern california with subtropical weather. gets pretty hot where im located over 40*c/ 104*f. But growth started emerging late February as we had some heat waves come in Feb so im thinking that kicked off the growth fairly early. i have come to notice this tree loves the sun so its placed in a location that receives full sun from 10am -6pm and loves it of course need to keep up on watering, been watering twice a day with a few days where i had to water 3 times and fertilizer helps too.
as for watering i currently use 1GPM drippers (you can get by with .5GPM but my water is to hard and clogs the tips) with 2 drippers on this tree since is has a bigger pot. but i only water with the system in case of an emergency or i cant make it home in-time for watering when its hot midday or im at work.