Can You Plant Irises in Spring? Here's What Horticulturists Say

Irises are hardy, low-maintenance perennials admired for their stunning flowers and diverse color palettes, which range from vibrant purples and blues to soft whites and yellows. With their elegant, sword-shaped leaves and unique blooms, irises can add a striking visual element to any garden.

Their ability to adapt to various climates and growing conditions makes them a favored choice among novice and experienced gardeners. Whether planted in clusters or individually, irises bring a vibrant burst of color and beauty to your outdoor space.

While irises are commonly planted in the fall, certain iris rhizomes thrive when planted in the spring. Below, iris experts share their professional tips for planting, growing, and caring for spring-planted irises.

Can You Plant Irises in Spring?

Irises are hardy perennials that can be planted throughout the growing season, including during spring. "If you’re purchasing rhizomes in the spring, there’s no reason to hesitate adding them to your gardens," says Josh Sullivan, product coordinator for flower bulbs and perennials at Fedco Seeds.

That said, iris rhizomes are more suitable for spring planting than true bulbs. Spring-planted irises typically grow from rhizomes—thick, fleshy root structures with visible root nodes. It's better to wait until fall to plant iris bulbs.

Benefits of Planting Irises in Spring

Iris flowers have a specific growth cycle that aligns perfectly with spring planting, allowing their roots to be established before the summer heat arrives. This early start gives irises the best chance of producing stunning blooms and lush foliage. "Planting in the spring provides the rhizomes with a long growing season to establish themselves,” says Sullivan. Additionally, spring's frequent rain and warm soil ensure newly planted irises receive ample water and the necessary temperature to grow.

Types of Irises to Plant in Spring

Successful spring planting depends on the type of iris used. According to Sullivan, irises that are suitable for spring planting include:

• Bearded irises (Iris germanica)
• Siberian irises (Iris sibirica)
• Japanese irises (Iris ensata)
• Dwarf iris (Iris danfordiae)
• Netted iris (Iris reticulata)

How to Plant Irises in Spring

Planting irises in spring is easy. For best success, however, Liz Schmidt, third-generation owner of Schreiners Gardens, recommends planting them in a location with well-draining soil that receives at least six to eight hours of full sun.

1. Choose a location with well-draining soil and full sun.
2. Using a garden fork or tiller, loosen the soil to a depth of 12 inches. This will allow the roots to move freely through the soil.
3. Dig individual holes 4 inches deep and 10 inches wide (or large enough to fit the rhizome). Place the holes 12 to 18 inches apart.
4. Create a narrow mound of soil at the bottom of the hole and center the rhizome on the mound with the roots spread out and facing down.
5. Fill the hole with soil to about ground level, leaving the top of the rhizome exposed.
6. Water every few days until new growth is evident.

How to Care for Irises

With proper care and the right conditions, your irises will thrive, producing an abundance of blooms and healthy, slate-green foliage year after year.

Sunlight

Irises need six to eight hours of sunlight daily. While irises can tolerate partial shade, the blooms will be less prolific.

Soil

Irises enjoy slightly acidic, well-draining soil rich in organic matter. The soil should be friable and crumble in your hands. Schmidt recommends amending compacted or heavy soil with garden humus or compost to help prevent root rot and improve drainage.

Water

Although irises are drought-tolerant, Schmidt says it's essential to water them regularly for the first couple of weeks after planting to establish the roots. If your area experiences extreme periods of drought, watering mature plants once a month will suffice.

Temperature

Irises do well in warmer conditions, ranging from 60 to 80 degrees Fahrenheit. If you experience frigid winters, Schmidt recommends providing winter protection by mounding soil around the plants and covering them with pine boughs or weed-free straw.

Fertilizer

Apply a balanced, slow-release fertilizer in early spring, approximately six to eight weeks before your irises bloom. Apply the fertilizer again after the blooms have faded.