I live in the Chicago area. I have had a bed of lilies of the valley for years, in my yard, about 4' wide x 15' long. This year was a hot, very humid summer. We had some rain, inconsistent, and I am pretty good at watering my yard, my containers, and so on.

Many of my lilies of the valley browned up and withered away already (mid Sep) while some are still looking good. Will the shriveled up ones come back in the spring time?

Can I transplant NOW the good looking ones from the back of the bed to the thinner areas -- if not now, when? And how deep down do you need to dig them out to transplant successfully?

Much appreciate any guidance you can provide. Thank you!

In my experience lily of the valley is incredibly tough, I've seen it growing through gravel and through pavement cracks. If you can dig up some of the roots with 'pips' and replant they should be fine. Whether you do it now depends on how much time they would have to grow more roots and settle in before winter.

The plant can be sulky however, so I would plant some roots in a couple of different areas if you can. Hard to say if the shrivelled up ones will recover, you will see in Spring.

Good luck.

Ditto on sulky....
Sounds like exactly the best thing to do if you want to ruin the patch!

Lilies of the valley is considered a bit of an invasive, in the north, we can't hardly grow it at all down here.

It's been my observation that spreading plants that look good on the edges.... And dead in the middle benefit from being left alone.

At a guess, the spreaders have exhausted the nutrients in the middle... And moving the plants that have escaped into better soil.... Back into the poor soil is not helpful.

Was me....
I'd spread some compost in the middle... And let them recolonized that area in their own time.