ROS should survive your zone - they do mine and I'm a high 5/ low 6.

Since they are newly planted, make sure they get lots of water this fall so they establish their roots. Water deeply at least once a week if you don't get an inch or so of rain during that week.

Do not fertilize. Especially if using a high nitrogen fertilizer. It's best not to encourage growth above ground at this time of year. You want the plant to concentrate on roots.

When things get really cool, mulch. You can use shredded leaves - these are the best. A 4 inch mulch above the root area will be sufficient.

In the spring, be patient. ROS has a nasty habit of leafing out late and a lot of folks think they are dead and take them out too soon. Don't, and if it gets through, you will be rewarded with a beautiful plant in bloom next fall!

Hi. I have tried to grow Rose os Sharon in my garden for three years now. Each year they died. This is at our farm in Z5a. We have heavy clay soil and the winter temps can be down to -30C. We don't have our house up yet, we'll be building next year, so the site is open and windy. It can be extremely windy in winter. My neighbour has a large Rose os Sharon bush in her yard so I get my seedlings from her. Tiffy, thanks for the advice. I'm going to try once again. Hopefully this time it will survive. Marg

Great advice, Tiffy. I am in zone 5 Canada, and my ROS is planted near a patio and my pond. There is a constant breeze coming up from the river. It comes through with no special effort at all, but as Tiffy mentioned in the spring it does take a long time before it starts to leaf out.