Where the end grain of pine has significant bands of different hardness in the growth rings I first drill a very fine pilot hole then follow that up with another larger pilot hole about half the width of the snail of the auger. This reduces the risk of a wandering bit.
As an update, I made the vases using an augur bit in the end, but I had to finish the taller one with a normal bit, to get the full depth for the test tube that goes down the center of the vase.
Took a few minutes to tune the auger bit in, bit once that was done, and with judicious use of the oil in a can, I was able to bore the holes with no real bother.
I had thought I would have to use a power drill for this (the auger bit is a hex shank), but after grinding down the shaft of a 3 jaw chuck spindle, I was able to do the boring by hand.
Apologies if the image looks a bit strange, I am not sure how well the whatsapp image will upload.