Is it to hot to plant knockout roses?

Plants that come in a pot can be planted year round.

You should not have a problem.

I have a knockout rose that I got right after Katrina to put in my front yard garden and this time of year it struggles to put out roses of any quality.

Most of them are scrawny and don't last even a day with our heat.

I'd plant it and keep it watered well until it properly roots, but don't expect any roses until late fall is how I see it going.

Knockout roses are really hardy you should be fine.