Dividing forget-me-not

Asked April 17, 2019, 4:14 PM EDT

I have an established rock garden that includes a 4x4 patch of perennial forget-me-not. It is blooming a beautiful sky blue now. I didn't get a chance to divide the plant before it flowered this spring. Can I divide it this fall (late August), or should I wait until next spring?

Arapahoe County Colorado

1 Response

The rule of thumb is:

  • Spring and early-summer blooming perennials are normally divided in the fall.

  • Mid- to late-summer blooming perennials are divided in the spring.

  • Iris and daylilies (rhizomes) are divided right after flowering.

So, your Myosotis sylvatica (Forget-Me-Not) should be divided in the fall—before the ground freezes or when the foliage dies back (mid-September to mid-October).

CSU information on dividing perennials: