Sunburned Lilacs?

[SCGirlGrower]

Hi there..I planted a lilac bush in a half barrel in May and it has been doing great until it started getting quite hot here. I had the barrel in a location that was recieving some morning sun and all of the afternoon sun. The leaves look sunburned...brown and dried out. I have since moved the bush to a location that gets a bit more shade in the afternoon and am watering more often. Does this sound a) like sunburn and b) is there anything I can do to help it out besides move it and water more? Thanks!

[Newt]

Hi SCGirlGrower,

I realize it's been a long time since you posted your question and I hope you've gotten some help with this. From your location your lilac could be Ceanothus aka California lilac or Syringa vulgaris aka French lilac or Syringa persica aka Persian lilac.

If your lilac is a Ceanothus the most common reason for what you are seeing is overwatering and heavy soil. Here's what Ceanothus looks like at the first site. Note the shape and size of the leaves of these different varieties.
https://www.laspilitas.com/groups/ceanothus/california_ceanothus.html

This explains the growing conditions they prefer.
https://findarticles.com/p/articles/mi_m1216/is_n3_v188/ai_12137271


Here's what Syringa vulgaris aka French lilac looks like. Note the shape of the leaves. These tend to like cooler growing conditions then where you are.
https://www.ces.ncsu.edu/depts/hort/consumer/factsheets/shrubs/syringa_vulgaris.html

Here's Syringa persica aka Persian lilac. These also prefer cooler conditions.
https://www.ces.ncsu.edu/depts/hort/consumer/factsheets/shrubs/syringa_xpersica.html

Syringa can get several diseases. There is one called bacterial blight.
https://www.ipm.ucdavis.edu/PMG/P/D-WO-PSYY-FO.001.html
https://plantclinic.cornell.edu/FactSheets/LilacBactBlight/lilacbactblight.htm

Leaf scorch is a possibility but is usually most prevalent on the side of the plant most exposed to sun and wind. You can read here on the symptoms.
https://ipm.uiuc.edu/diseases/series600/rpd620/index.html

Ascochyta blight is a fungal disease.
https://www.extension.umn.edu/projects/yardandgarden/ygbriefs/p467lilac-ascochyta.html

Newt