Photo with one leaf:

Photo of the whole plant:

It can take a whole growing season for any plant to grow enough of a root system to start the top growth. Too much water can be as much of a problem as too little, but !/2 gallon of water every day might not be enough. How moist is the root ball? What type of soil is this Lilac planted in? Does the soil drain really well or is it water logged?

your base problem.. is that you thought that a NEW TRANSPLANT.. would be vigorous and explode in growth ..

all i expect the first year.. is for it not to die ..

you water when it needs it.. and you find out by inserting your index finger.. or digging a small hole next the the part you planted.. and insuring that it is damp thru the whole root zone .. and then NOT watering again.. until it near dries.. NO GUESSING ...

i would NEVER feed nor amend the soil on a new transplant..
IMHO.. lilac NEVER needs fert ...

and you need a nice circle of mulch around it ...

and in 40 years of owning lilac.. i never used a chemical nor bug solution ever.. the leaf damage looks mechanical.. not chewing.. shipping damage?? hail??? dog.. kids???

lilac also needs full sun .. is yours in full sun???

you are on the verge of trying to love it to death ... water PROPERLY.. and step away from it ...

and forget about some special CO winter rules ... if properly watered.. and happy going into fall.. it should be bulletproof ...

water deep into fall.. but do not allow it to freeze its roots in a manmade ice cube ...

ken

kimmsr and Ken - Thank you very much for your ideas. I learned a lot.

My husband planted it while I was away. He told me he dig a big hole and planted it into gardening soil. The soil condition should be favorable given he used almost a whole bag of gardening soil.

It is in full sun.

I won't feed it again.

There was no leaf damage when I bought it. All my neighbors do own dogs (I don't) but they seem decent enough to keep their dogs from biting other people's plants...

I now think it was hail.

on looking again.. it looks like cutter bees may have gone after the edges ...

if it is.. its not something i go after ...

ken

Here is a link that might be useful: link

Darth...never fertilizing your shrubs is not the advice you'll get from most sources. The need to provide fertilizer depends upon the existing soil...in the present and the past. I see that you are not using a traditional bark/pinestraw/wood chip mulch. Are you applying compost on a regular basis? If not, I'd bet that your plants would benefit from conservative applications of a low nitrogen fert. Stop any fertilization by late summer...you want your plant to be hardened off before winter.

The one thing I worry about, though, is the use of planting soil when installing this plant. Plants do much better when planted directly into the native soil, no matter what the condition.

Yep, looks like leafcutter bees have been at work. That and some miscellaneous physical damage. Your lilac can recover from both.

Ken and rhizo - Thanks a bunch. I Googled leafcutter bees. Seems they don't do real damage to plants.

I will stop worrying, keep watering regularly, and put mulch around the plant.