You don't trim the gazis until they are dormant.
Gazi is a replacement for the Lombardy Poplar. This tree is originally from the Poplar Research Station in Turkey. it is a pure Populus Nigra, not a hybrid. This tree is resistant to canker, insects and to cold. It has grown with no problems in Minnesota. Grows to 75 ft. in about 10 years.
I plant about 100 of them every year to be sold between April and August.
All trees are now big enough to ship. You can have poplars, gazis, American Sycamore or common privet for a total of 8 trees. I try not to ship close to the weekend, I want the trees to be delivered to you on the same week I ship them, so I ship a lot of boxes on Mondays.