This is my first year growing Siberians, and the same thing happened to me - they all turned brown, and I watered them pretty good. I'm hoping they'll just show some new growth in spring. Actually, I think I have a species Siberian that had some new growth, but all the hybrids/cultivars turned brown on me.

Tug on them to see if they have rooted. If so, you may get spring growth. If not, probably dead.

If you took good care of them and they still died, contact the company you purchased them from and put them on motice that the plants are not doing well, and then let them know how they do in the spring. Most places have some guarantee on their plants.

Siberians are easy to grow, and if you plant them right away, when received, mulch them well, and keep them watered they should certainly grow for you. But let the supplier know, they will want to help.

And PS, if they came from me, please let me know, and I will certainly replace or refund.

Polly @ Siberian Iris Gardens