How to Plant Bearded Iris

Plant bearded iris July through September with the top of the rhizome exposed at soil level, 12–24 inches apart. Planting too deep stops the bloom.

When to plant
July through September, at least 4–6 weeks before your first hard freeze
Depth
Top of the rhizome exposed at soil level, roots spread downward and covered. Up to 1 inch of soil over the rhizome only in hot climates or very light soil
Spacing
12–24 inches apart
Sun
At least a half day (6–8 hours) of direct sun
Water
Water in at planting, then only when the top 3 inches of soil are dry
Soil
Well-drained, pH around 6.8; use a slope or raised bed in heavy clay

Step by step

  1. Pick a site with at least a half day of sun and fast drainage; a slope or raised bed is ideal in heavy clay.
  2. Dig a shallow hole with a ridge of soil down the center. The rhizome sits on the ridge and the roots hang down either side.
  3. Set the rhizome so its top stays exposed at the soil surface, then spread the roots down and cover only the roots.
  4. Firm the soil around the roots and water in to settle it.
  5. Space rhizomes 12–24 inches apart, with the fan of leaves pointing the direction you want the clump to spread.
  6. Leave the rhizome uncovered and don't mulch over it. The top needs sun and air to stay dry.
  7. Water again only when the top 3 inches of soil dry out. Overwatering is the most common way to lose a rhizome.

After bloom

Snap or cut each bloom stalk off at the base right after it finishes. Leave green leaves through summer to feed next year's flowers; trim only brown or spotted ones. After fall frost, cut the foliage back to about 6 inches and clear every clipping from the bed. Old leaves carry soft rot and iris borer. Feed with a low-nitrogen fertilizer such as 5-10-10 in early spring and about a month after bloom. Divide crowded clumps every 3–4 years in July or August, 1–2 months after flowering.
Shop all bearded iris →