Sounds like a good assumption, especially if you have multiples of the same plant acting the same in that spot. It might be time to try something else.

The lilacs that aren't doing well are in the low spot in our yard about 100 feet away from the house. While the lilacs closer to the house in a much dryer location are beautiful.

The reading I have done suggests that lilacs do not like wet feet and can even rot. The "Miss Kim" (which are also dwarf) that I planted about 3-4 years ago were about 12 inches when planted and are now about 3 feet. The drainage is good and I amended the soil before planting.

Is there a way you can relocate the lilacs? They are still alive but not growing, right? I'd try to find a drier home for them and try something else that requires a wetter spot.

Good luck!
Kristy :)