Hi Jill,

Sorry to hear about your lilacs, and thank you for sending us pictures so that we can start to help identify the problem. Based on what we know so far, we don't think that your lilacs are suffering from a disease, but that they might be suffering from stress or from some sort of environmental factor. We have several follow-up questions for you that will help us arrive at a better diagnosis:

When was the gravel mulch put in, and is there landscape fabric under it?

How long has the turf been there/was the turf recently put in?

What does the watering schedule for the lilacs look like (including for fall and winter)?

What, if any, fertilizers, herbicides, or weed killers have been used on the lilacs or nearby turf?

Where are the lilacs located (in relation to each other, and throughout the yard; we know three are close to each other, but where are the other two lilacs in relation to those three)?

How often have the lilacs been pruned?

In the meantime, we are including a few resources for you to take a look at. Here is an info sheet on abnormal plant growth, here is a resource on mulching (including using rock and gravel mulches), and here is one more fact sheet on healthy roots.

Thank you for reaching out, and we look forward to hearing back from you!

Also, would you mind sharing your zip code? We are collecting this info to help us better serve our local gardening community.

Caitlin W. and Jessie A.