Thujas Doing Well in Zone 5 Despite Poor Soil

Bought 45 Thuja Giants as a privacy border nearly 2 years ago. Each plant has thrived and grown nearly 2ft in that time despite my Zone 5 location and very poor soil conditions and with little care. I also tried planting white pine and hybrid willows in the same location. All died. Although I am a bit disappointed at the rate of growth (advertised at 4ft per year), these specimens will thrive and outlast me and my ownership of this property. Hope the next owner appreciates them as much as I.