Spring is a great time to divide perennials. It's better to do it on a cloudy day, not humid, and keep well watered after dividing.

Jen

I'm thinking this is the BEST time to do it.

Somebody left me some spiderwort on my front porch last year around the first week of June, that was in bloom. I stuck it in the ground, and it kept blooming the whole summer, and is starting to bloom again now. I think it will be fine.

Ladies, thank you much. Think I'll be doing it first thing tomorrow morning. The coolish weather puts me in the mood; wish it would stay around 60-65 degrees year around.

I wanted to share how we divided the spiderwort this spring, well, a daylily too. We used a bulb planter. Just thinned out the middle of the larger plant, you couldn't even tell after a week or two. Maybe not the correct way - but it works for me.
Penny

I have found that some plants are very tough and can be moved or divided year 'round (with proper care of course). However, the rule of thumb is spring bloomers should be moved in the fall, and fall bloomers should be moved in the spring....There are some things I follow this addage for --such as poppies, but others I move willy nilly.

I whole heartedly agree with the suggestion to provide shade. My neighbors here think I am nuts when I drape sheets, put chairs over the top of or otherwise coddle newly divided/moved plants. Of course, there's only one gardener in the lot of them....everyone else has people come in and "landscape" then care for them.....

Spiderwort is a very tough plant. Enjoy!