How to Plant a Purple Bearded Iris


Bearded purple iris has unique flowers with petals that hang beneath the center of the flower. Purple bearded iris is one of the more common colors of this plant that features drooping petals with dots or markings. Learning how to plant a purple bearded iris requires finding the perfect spot for your iris bulbs. Purple bearded iris works well planted behind smaller-growing perennials or annuals since the stalked can grow up to 38-inches tall. Adding soil amendments, proper watering and spacing should be considered when planting purple bearded iris.

Step 1

Select a spot in full sun to encourage full blooms. Soil should have adequate drainage to prevent rotting of the iris bulbs.

Step 2

Examine the iris bulbs to check for rotting, drying or damaged areas in the bulbs. Bulbs should be firm to the touch, with no indentations or discoloration.

Step 3

Plant new bulbs between July and September to allow plenty of time for the plant to become established before winter. Plants will bloom the following summer. Place bulbs in groups of three for best results, spaced 10 inches apart. Allow 18 inches of space between larger clumps of bulbs.

Step 4

Stir up the soiling your planting bed to a depth a 6 inches. Use the shovel to loosen the soil by digging up this layer. Loosened soil allows plants to spread roots more easily and take advantage of any organic soil amendments added to the garden bed.

Step 5

Mix in three parts peat moss or compost to the volume of soil in the planting area. Stir up the soil again using the shovel to work the peat moss into the top 6 inches of soil.

Step 6

Add the appropriate amount of fertilizer based on the size of the planting area. Mix this treatment into the soil using the same method used for incorporating the peat moss.

Step 7

Dig a shallow hole that will allow the purple bearded iris bulb mass to lie slightly above the soil surface level. The hole should be large enough around to provide enough room to include newly amended dirt to reach the bulb clump. You want to surround the plant with enriched soil to encourage healthy bulb growth.

Step 8

Place the bulb clump into the hole and fill in around the clump. Make sure the top of the bulb mass lies above soil level. Add or remove soil from beneath the bulbs until correctly positioned.

Step 9

Continue filling in around the plant, firming the soil with your hands. Mound the soil about 2 to 3 inches above the soil surface level and apply a 3-inch layer of mulch to keep soil temperature uniform.

Step 10

Water the bulbs deeply after initial planting. Iris prefers dry soils and doesn't respond well to overwatering. Bulbs will rot easily in wet clay soil. Soil should be moist when touched your finger but not soggy wet.

Things You'll Need

  • Spade shovel
  • Peat moss
  • Fertilizer
  • Mulch
  • Water and garden hose


  • North Carolina State University
  • Cornell University
Keywords: purple bearded iris, planting iris, irs bulbs

About this Author

Currently studying for her Maryland master gardener certification, Sharon Heron has written professionally since 2006. Her writing includes hundreds of articles on a wide range of topics including gardening, environment, golf, parenting, exercise, finances and consumer how-to articles.