It could be that when you separated the 2 plants, you lost alot of the root system of each and thus the plants are compensating by aborting some of the existing growth. Meanwhile, they're both probably growing brand new roots (ie., often when nothing is happening on top, something is happen underground). I think patience is in order and hopefully some new growth will sprout soon.

Thank you SB for your input. During its first season I had it in a full sun location and browning of the buds occured. The people at Sheridan Nursery where I bought it from suggested it needed some afternoon shade and so I moved it to a partial shade location with sun until 1 pm and it was still happening. Now I'm still seeing the same thing. Could it be as a result of some nutrients my soil is lacking? This spring I added 2 inches of compost and 2 inches of mulch and 1 round of slow release all purpose fertilizer. My other phloxes are just coming into bloom as well....and you are probably correct about the reason as to why the browning of some of the leaves on the bottom of the stems as a result of overwatering and poor drainage. This year we have been getting a lot of regular rainfall in Toronto and I have not had to use my hose as often so I'm not seeing that yet! It would be nice to find out if anyone else have seen this happen to their Tiara as well. The picture on the tag for Tiara is so pretty and I have been looking forward to seeing it in person ever since I bought it.

There is a shock from relocating out of warm humid greenhouse by the way of semi trucks to the store and to your much drier house. Can cause blossom drop. Or this bud stem was someway damaged on the way. None of these are a problem. AV will adjust and give you more blossoms in time. Congratulations with your very pretty purchase. i.

For anyone else looking for information, I dug this up. This is the best site I've found with information about hybridizing. Here is a link that might be useful: Jeff Smith's Notes on Hybridizing