Planting and Growing Bearded Iris

Flamboyant blooms on stately plants grace the garden in June. Bearded Irises come in a rainbow of colors—vibrant primaries, subtle bicolors, gentle pastels. Reblooming varieties may flower again from late summer into fall depending on climate. Note: Bearded Irises may not bloom the first year after planting.

Light/Watering

Full sun and well-drained soil are essential. Do not overwater—excess moisture causes rhizome rot. Water deeply during summer drought. Consistent watering is especially important for rebloomers.

Fertilizer/Soil and pH

Iris will not tolerate wet winter soils. Good drainage year-round and pH near neutral (7.0) preferred. In hot summers, plant rhizome just below soil surface; in cooler climates, leave top exposed. Do not mulch around rhizome (encourages rot). Fertilize early spring with all-purpose fertilizer scratched in around plants, avoiding rhizome contact. Rebloomers benefit from a second feeding after first bloom wave.

Pests/Diseases

The iris borer is the worst pest. Eggs overwinter in spent leaves—remove foliage to deny hiding places. Borers emerge as tiny caterpillars in spring, boring down into rhizomes, causing soft rot. Vigilance helps: vertical streaks in leaves indicate borers; squash them. If rot appears, dig up and remove affected parts. Well-drained soil and planting with rhizome top above soil line prevent soft rot. Discard affected rhizomes.

Companions

Best with other perennials: Lilies, Herbaceous Peonies, Roses, Oriental Poppies. Allow enough space for good air circulation.

Reflowering

Remove spent blooms consistently; flowers open sequentially. After blooming, cut flower stems at base. Rebloomers may send up new fans with flower spikes later in season, but not guaranteed. Repeat bloom depends on location and conditions.

Dividing/Transplanting

Divide when clump becomes crowded and bloom diminishes, usually every 3–4 years. Unlike most perennials, Bearded Irises go dormant after flowering—summer is ideal for division. Even rebloomers should be divided then. Break or cut rhizomes into pieces with healthy leaf fans (from outer plant). Discard crowded interior pieces and any with rot (trash, not compost). Trim leaves to 6 inches. Optional: dust cuts with sulfur or dip in 1:10 bleach solution. Replant promptly. Share extra divisions.

End-of-Season Care

After hard frost, cut foliage hard, remove spotted/yellowed foliage, dispose of debris in trash. Winter protection recommended in cold climates, especially first year. After ground freezes, cover rhizomes with 1–2 inches of sand topped with evergreen boughs; remove when Forsythias bloom next spring.

Calendar of Care

• Early Spring: Remove and destroy old foliage to prevent borers. Remove winter mulch. Feed with all-purpose fertilizer around plants.
• Mid-Spring: Watch for borer signs (dark vertical lines). Squash bugs; if severe, remove and destroy affected foliage.
• Late Spring: Stake taller forms. Deadhead faded flowers; cut entire spikes at base when blooming finishes. Fertilize rebloomers after first wave.
• Summer: Divide if needed after flowering; trim foliage to 6 inches. Water divisions during dry periods.
• Fall: After hard frost, cut foliage hard, remove spotted/yellowed foliage, dispose of debris. Winter protection as above.