09/06/2026
Great info to share!!
The perennial with a dead middle and a ring of flowers around the edge isn't dying.
It's asking to be divided.
Clumps grow outward and starve their own center. Splitting them is just finishing what the plant started, and September is when it pays off: the soil is warm enough for new roots, the air is cool enough that the top isn't stressed, and there are six to eight weeks before hard frost.
There are three kinds of root, and each one comes apart differently.
🌿 Nine to divide this month:
- Bearded iris – Thick rhizomes at the surface. Snap into pieces, each with one fan of leaves, toss the woody center, and replant with the rhizome top showing. North of Zone 6 this is a July job, so wait for next summer.
- Peony – Brittle roots, so dig wide and wash the soil off. Cut the crown into sections with three to five pink eyes, and set them 2 inches deep. Any deeper and it stops blooming. Fall is the one time peonies take this well.
- Daylily – Dense fibrous mat. Two garden forks back to back through the middle and pry. Keep divisions with three to five fans, trim leaves to 6 inches.
- Hosta – Slice straight through the crown with a spade once the leaves start yellowing. Hostas shrug off rough handling. Each piece needs two or three pointed buds.
- Coneflower – The classic donut. Pull the live outer ring apart by hand, compost the dead middle, space the pieces 18 inches.
- Shasta daisy – Same donut, faster. These wear out in three or four years without a split. The roots separate easily.
- Garden phlox – If it gets mildew every summer, the clump is too tight for air to move. Divide into sections of three to five stems and give them 18 to 24 inches. Spacing is the cure.
- Bee balm – Shallow runners, same mildew problem. Dig the outer pieces you want, leave the tired center behind, cut back to 4 inches after replanting.
- Black-eyed Susan – Spreads by runners until it owns the bed. Lift sections from the edges with roots attached. The parent patch doesn't miss them.
Afterward, water deeply once and mulch 2 inches. Skip fertilizer; the plant needs roots right now, not leaves.
Divisions made in September bloom next summer. Spring divisions often sit out a year.
The center dies so the edges can live. 🌱