Iris ‘Gossamer’ is a specific variety of Tall Bearded Iris. It’s important to keep this in mind as general iris care can sometimes differ slightly from specific bearded iris care.
How to Grow and Care for Iris Gossamer
Iris ‘Gossamer’ adds captivating elegance to any garden. This popular iris variety offers unique appeal, enhancing landscapes with its distinctive presence and graceful form. Its striking aesthetics combined with straightforward cultivation make it a favored choice for a beautiful display.
Understanding Iris Gossamer
Iris ‘Gossamer’ displays a unique palette of colors and delicate structure. The upper petals, or standards, are a soft peach-buff, while the style arms are peach-cream with a subtle lavender midrib. The lower petals, or falls, showcase greyed violet to lavender, subtly shaded with bisque, and a narrow columbine blue flush extending from the beard to the petal’s edge. This tall bearded iris typically reaches 38 inches (97 cm) tall. Fine textured veining on the falls becomes more pronounced as the flower ages, adding depth. ‘Gossamer’ generally blooms midseason to late spring, offering sustained vibrant color.
Ideal Growing Conditions
Iris ‘Gossamer’ thrives in full sun, requiring at least six hours daily for abundant blooms. Without ample sunlight, ‘Gossamer’ will not flower prolifically. Well-draining soil is essential, as irises are susceptible to rot in waterlogged conditions, especially during colder months.
A slightly acidic to neutral soil pH (6.5-7.0) supports optimal growth. Once established, these irises tolerate dry conditions, but moderate, consistent moisture during their active growing season promotes vigorous development. ‘Gossamer’ is hardy in USDA zones 4 through 9.
Planting and Cultivation Techniques
Soil Preparation and Planting
Proper planting begins by loosening soil 12 to 15 inches deep, optionally incorporating two to four inches of compost for improved drainage and fertility. Create a shallow hole, about four inches deep and ten inches wide, with a small soil mound in the center. Position the rhizome on this mound, spreading roots downwards, ensuring the top is at or just below the soil surface. This shallow planting allows the rhizome to receive sun warmth, important for flowering. Space rhizomes 12 to 24 inches apart for air circulation and to prevent overcrowding, which inhibits blooming.
Watering and Fertilizing
After planting, water rhizomes thoroughly to establish root systems. For ongoing care, apply fertilizer twice yearly: in early spring as new growth emerges (before buds), and immediately after blooming. Use a low-nitrogen fertilizer (e.g., 6-10-10 mix), as excessive nitrogen promotes leaves over flowers. Apply granular fertilizer in a ring around the root zone, avoiding direct rhizome contact, then scratch into topsoil and water well.
Deadheading and Dividing
Deadheading spent blooms prevents seed production, directing energy to strengthen the rhizome for future flowering. Cut the entire flower stalk down to its base, about an inch above the rhizome, once all blooms fade. Divide irises every three to five years, typically four to six weeks after flowering, to rejuvenate overcrowded clumps and maintain vigorous blooming. Lift the entire clump, discard old or diseased sections, and replant healthy divisions, each with a fan of leaves and firm roots.
Common Problems and Solutions
Bacterial Soft Rot
Bacterial soft rot is a significant concern for Iris ‘Gossamer’. This infection causes rhizomes to become soft, mushy, and foul-smelling, often collapsing leaf fans. It typically enters through rhizome wounds, worsened by warm, moist conditions, poor drainage, or overcrowding. If detected, carefully dig up the affected rhizome, scrape away all infected tissue with a sterilized tool, and allow the healthy portion to dry in the sun before replanting. Disinfecting tools prevents further spread.
Iris Borer
Iris borer is another common pest that can lead to bacterial soft rot. The moth larvae tunnel through leaves and into rhizomes, causing damage like water-soaked spots, ragged leaves, or wilting. To manage borers, remove and destroy old iris leaves and plant debris in late fall to eliminate overwintering eggs. In spring, inspect plants for early tunneling signs and crush visible larvae. For severe infestations, apply insecticides with azadirachtin or spinosad when new shoots are four to six inches tall, with a follow-up 10 to 14 days later.
Non-Blooming
Non-blooming is a common problem. Insufficient sunlight is a frequent cause, as irises require ample sun for flowers. Overcrowding also diminishes flowering; dividing dense clumps every few years helps. Planting rhizomes too deeply can prevent blooming, as they prefer to be near the soil surface. Over-fertilization with high-nitrogen products can also lead to lush foliage at the expense of flowers.