Time to dig and divide perennials
This coming autumn you may want to take a close look at your perennial plants such as:
Bee Balm (Monarda)
False dragonhead (Physostegia)
You'll want to look for:
1. Overcrowding - or a tight mass of roots and stems
2. Die off in the center of the plant
3. Overall appearance, if the plant lacks vigor or looks shabby
4. Smaller or no recent flower production
5. Plants that are simply getting too big
If the above is happening, the cooler fall months are a good time to dig and divide your plants.
The General Rule of Thumb:
The general rule is to divide spring and summer-flowering perennials in late summer or fall, and to divide fall-flowering perennials in early spring. Division rejuvenates perennials, increasing flowering, and improving the overall appearance.
If you live in a very cold-weather climate, make sure you do this early enough, about 6 to 8 weeks before a hard freeze, so that the plants have time to root and get established before it gets too cold. If you can't do it early enough, then wait until spring.
What To Do:
1. Simply dig up your perennials
2. Separate them into healthy sections
3. Get rid of any plant material that looks woody, dead, or diseased
4. Replant the pieces
5. Water them in and keep moist until they are rooted