Q.lilacs
My lilacs are starting to get leaves but some of them have started with brown leaves instead of green. Is there a problem? Will they be all right? My plants are dwarfs and this is their fourth year with me. Thank you.
You will need to do some further inspection of the plant.
Look for any other leaf issues that may help determine if the leaf damage is Lilac Bacterial Blight.
Has is been dry or excessive rain or wet conditions?
The leaves could be showing signs of either condition.
Here are some links with more information.
http://extension.oregonstate.edu/gardening/how-recognize-treat-and-avoid-lilac-bacterial-blight
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/dwarf-lilac-varieties.htm
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/common-lilac-problems.htm