Personally, I wouldn't take a chance dividing them now with the current heat waves and everything. I usually cut mine back about half way after the flowers fade. I would divide in fall or spring.If you do it in fall and you cut them back first, the roots won't have to stress at feeding as many leaves and can concentrate more on developing themselves. In spring the top growth will be small and you will get the same result.What kind of Monarda are you growing? I've been growing the native M.fistulosa for years and it hasn't spread a lot until just recently,but they still have plenty of area I want to cover.This year I planted the red flowered M.didyma and it has done really well and currently is putting on a show. I'm really hoping the M. didyma spreads so I can have a lot more for the Ruby Throated Hummingbirds.

Thanks for the advice

The variety I want to divide are Jacob Cline. Other varieties that I am growing are:

Gardenview Scarlett
Purple Rooster
Marshall's Delight
Grand Parade
Wild Bergamont

The garden bed looks like a collision of Monarda, it is not very neat. I was going to start tidying it up by dividing the plants to give them some separation rather than having them all mashed together.

Based on your advice, I will wait to do this. I need to mark the different varieties somehow, so that when it does come time to start dividing and moving, I know which plant is which, they are all that close together.

Having mostly monarda in one bed, with them all close together, was not a wise move. The garden looks pretty sad after the peak monarda bloom time.

If they are still blooming, so you can tell them apart,tie a string around all the stems of one cultivar and do the same with the others.Sometimes each one will have a distinctive leaf which could be another way to tell them apart.Hope you have luck with at least one of those.Now I understand why you'd like to divide now.If you don't mind me switching gears, I suppose it would be ok to divide them now, if you cut the plants halfway immediately after replanting.You would have to make sure that they stay moist and don't dry out and maybe even shade them on really hot,sunny days.After 2,3 weeks you will be able to tell that they are settling in when they start getting more healthy color and texture.Monardas are in the mint family and all mints are programmed to survive and very hard to kill.Dividing them now might set them back slightly,but with good care they should bounce all the way back no problem next year. I'm sure if you google dividing Monarda there will be a lot of articles with more information about it.Good luck.

Hey KC, I just read an article and it said to wait until your plants are done flowering before dividing.So I don't know how far along yours are.My fistulosas are just about done,but the didyma has maybe another week or two. I would still cut them back and keep them moist, but with good drainage,not waterlogged.Hope this helps.Just make sure to do it while you can still tell them apart. I'm still moving plants around and doing some editing even now near the end of July. I just have to baby them more when I do it this time of year.