I plant white pine and white spruce. White pine has done better in my heavy clay soil. Probably have a 70% survival rate with the spruces and 100% with the pines. Rototilling a spot and amending a bit does way better than using a dibbler.
IF not watering, invest in some mulch. I buy bunch of bags when they're on sale or clearance. Woodchips are good if you can get them too.