I recently bought some plants from a french nursery. Two of the smaller ones have hollow stems at the bottom where, presumably, the cutting was first rooted. The new leaves above this seem healthy enough. Is there any cause for concern? I may wait until there is more growth then try to air layer.

I assume your young tree was from a cutting. Very often the soft center of the top of the cutting will die back to a node and appear hollow. This is normal. Most of the time I try to burry my plant a bit lower in the pot when I shift them up to burry the hollow stem and a couple inches of the main branch. This will allow the main branch to grow it's own roots. You can do this in the ground as well. No worries.

Thank you for the reply. I was worried that burying it might cause it to rot but you are right, it would probably root further up before that happened.

I second what Aaron said,seen that before where stem is left above the node on rooted cuttings,doesn't happen on mine as I trim to just above a node.I was worried about water sitting in the hole so checked it and found a little slug in there,probably eating the dead wood so I trimmed it off,was fine after.

If you don't mind me asking who did you order from and how did it go?,I want to order a couple of plants from a French nursery and have a few in mind but none seem to have all the plants I want in stock at the same time lol,maybe a positive recommendation will help tip the balance

It was a man on ebay, Jean-Marc, his ebay name is jeq-games. He was very nice and tried to keep postage costs down. When the plants arrived they were a little bashed up but have survived.

The temperatures in France were very high when he was packing them and he had watered them. The water had broken up the bottom of the box which meant the plants were able to move about too much.

What varieties are you looking for?