Ken's point about fall is that the plant is about to shed its leaves - foliage problems are really of no immediate concern at this time of year :-) Your leaf problem looks like typical lilac blight - and not a very severe case of it, either. This is a bacterial disease lilacs (and a bunch of other plants) are prone to. Tends to be somewhat climate-related and you can treat for it if you wish but I find it more of a cosmetic issue than a serious health threat, at least with an established lilac. Can be pretty gruesome with certain other plants, however. And pinhole insect damage to leaves is a no-brainer NBD and even more so at this time of year. Just make sure you rake up and properly dispose of all leaves this fall and then follow whatever treatment plan you prefer. A dormant spray with copper sulfate is often used in my area. Here is a link that might be useful: lilac blight fact sheet

it has been so terribly rainy this summer--many of my supposedly hardy, fool-proof plants are really suffering (lavender, rudbeckia, baptisia). Now my lilacs are looking poorly--everything I see about bacterial blight says it's a springtime illness, but I'm afraid that might be what this is. discrete brown spots on the leaves, light brown...do I need to prune them down to nothing? will they come back?

I bought this from the nursery 2 weeks ago ==>> first... i would talk with the owner of the nursery .. see what they say .. second.. i would presume a high end nursery.. would bring in 'clean' stock ... which bring me back to what i said above ... superficial leaf damage ... and who would expect a blight to infect and manifest itself.. in 2 weeks ... third ... i like the extension office idea ... if for no other reason.. to report the owner.. if he doesnt offer you satisfaction .. and the stock is in fact.. severely diseased .... this industry is regulated ... this shouldnt happen in 2 weeks... period ... ken ps: injured leaves.. can assume all kinds of weird looks ... but its still just a leaf with a boo boo ...

Ah, the Hulda Klager Lilac Garden! Back around 1995 I was driving down the interstate in southwest Washington when I saw signs advertising the lilac festival there in Woodland. I turned off the road and went to visit it, and there began my passion for lilacs, which is unslaked to this day. Ken, I know about the USDA hardiness ratings, but the Italian climate is different from that of most of the U.S. Lilacs are a traditional, popular plant locally and do extremely well. The weather pattern here is that temperature lows aren't very low--many winters it never drops below 20F--but there's abundant winter chill, that is, temperatures in the low forties, thirties, and high twenties. This is why we can grow both Tea roses and olives on the one hand, and tulips, apples, and peonies on the other. Summers are traditionally dry and hot, and the lilacs may like that as well. I got into conversation with a nurseryman once who told me that lilacs had disease problems in the plains (the Po Valley), where summer atmospheric humidity is greater than here; but in the hills they're great. Our fabulous weather patterns may be changing, though, with climate change, so I'll see what happens. Carol and John, thanks for your ideas. The lilac in question is right by two other lilacs that are doing fine. The other two sufferers (and one was definitely diseased, with foliage damage that this one doesn't show) are located well away from this plant. I find it hard to imagine drought stress, drainage, or nutritional inadequacy being a problem, as the two neighboring lilacs are fine, and since the conditions are the same the lilac has been happily growing with for several years. They may not be great conditions in themselves, but lilacs like them. (N.b. I find this bizarre, but the spring flowering this year, for all plants, has been amazing, in spite of low precipitation since last summer. We seem to be getting enough rain to keep the plants happy....groundwater recharge is a different question. And it has been raining lately, with hints of more starting in a few days. In late years I seem to notice a trend toward drier, sunnier winters and wetter springs, Or is it just a fluke, or my imagination?) Carol, one of the baffling aspects of this lilac's behavior is that some inflorescences on the plant are normal, others look wrong; while the rest of the growth looks okay. I'm considering cutting out all the branches with the bad flowers, even though they otherwise look healthy. I did look up lilac diseases online before posting my question here, finding nothing that looked applicable. If we can maintain our gardening activity, perhaps we'll undertake more lilac planting in a few years, say, when DH is ninety (this is sarcastic! although he is in his upper eighties). I was down in the newer part of the big garden, close to the road. Seven or eight years ago, perhaps, we planted a hedge of lilacs, mixed varieties, along the southern boundary of the garden, and property. There had been a sizeable landslide on the land below ours, and the slide was propagating up into our property. So DH, who was seventy-nine at the time, went out with planks, heavy rebar, and a maul as big as he is, and got busy shoring it up, then planted hazelnuts in the upper part of the slumping area, and lilacs along the boundary. There were seedling oaks there, too, which have since grown well. The ground slumped a bit but is holding. The lilacs look great--they love the slope, clay soil, and full sun and wind--only we need a few more dark varieties to set off all the lavenders, pinks, and whites. I'm considering continuing the hedge along the line where the garden bounds neighboring fields below it. I'd like some new lilac varieties, too, so need to go looking for other suppliers. All this naturally assuming we can keep on gardening.