water properly .. and hope that they can reflush ..

its a bit early to start hacking them up ....

find the receipt if you have a warranty

ken

"I planted 3 Miss Kim Lilacs in my yard late in May."

May is pretty late for planted trees and shrubs. With pot-grown material, it is do-able, but isn't ideal. It certainly requires diligence with monitoring soil moisture and watering when necessary.

I planted according to the directions on the tag, and prepared the holes well, backfilling with a mix of bagged topsoil, compost, and native soil.

The instructions you depended on were incorrect. It is almost never a good idea to amend backfill soil. Whoever wrote those instructions apparently didn't know much about planting woody plants.

"I watered them after planting, but then we left town for 8 days."

Without knowing what type of soil and drainage you have and how much it rained, we can't know much about whether this was a problem, but it definitely is a red flag.

"One thing I did not do was separate the roots when planting...maybe this killed them?"

I'm not sure exactly what you did from your description, but you probably helped your lilac more than hurting it by addressing any pot-bound roots. I don't think your problem lies here.

As Ken said, find/keep that receipt if you have a warranty! Check out the link below for future plantings.

Here is a link that might be useful: Planting a Tree or Shrub

When first planted into the garden, roots are still confined to the original rootball. That area dries faster than does the surrounding soil. Even though the surrounding soil may be moist or even wet, water won't go sideways into the rootball. Further, the roots haven't yet extended outward.

Tada! Now we have the oft claimed "transplant shock."
But no. Not shock at all.
Instead, drought stress because the roots are dry.

"When first planted into the garden, roots are still confined to the original rootball. That area dries faster than does the surrounding soil."

Neither of these assumptions are always the case. Roots are only confined to the rootball if the root ball was not disturbed (which Ren920 actually claims to have done). Rootballs only dry out before the surrounding soil if 1. pore size of rootball material is larger than pore size of surrounding soil AND 2. moisture is insufficient to keep the rootball moist.

"...water won't go sideways into the rootball."

That statement is just false. Capillary action (a major component of internal soil drainage) can move water sideways (horizontally) equally as well as it can move water vertically.

"Tada! Now we have the oft claimed transplant shock. But no. Not shock at all. Instead, drought stress because the roots are dry."

This may indeed be the case, but we have little if anything to base this conclusion on, at this point. Unless you have a crystal ball, you are jumping the gun BIG TIME!

I planted a Miss Kim just before the 7+ week drought last summer. Even though I watered it, it looked like a goner. But it came back this year, so don't give up yet!

Anne

The biggest red flag is leaving town for 8 days and not watering. It looks like everything else was done correctly. It's unfair to pin this on the nursery when a newly transplanted shrub didn't get the deep watering that's essential the first season.

This thread is 7(!!!) years old, jenfreeman01!

Amending of planting hole back-fill during the planting of long term plants is never "correct", was being noticed as consistently tending to be detrimental in organized university level experiments by the late 1960s.