The Iris genus, named after the Greek goddess of the rainbow, represents a diverse group of perennial flowering plants known for their intricate bloom structure and vast color palette. Irises are grown from either a bulb or a thick, horizontal underground stem called a rhizome. Finding the specific variety requires knowing the various sources available, from local vendors to specialty sellers providing access to rare cultivars.
Purchasing Options for Iris Plants
Local garden centers and nurseries are excellent starting points, especially for new gardeners, as they provide plants already growing in pots. Purchasing a potted iris ensures instant planting and allows you to physically inspect the plant’s health before purchase. Big-box stores and seasonal plant sales may also offer common iris varieties, particularly bearded iris rhizomes, during peak planting times.
Online mail-order nurseries and specialty hybridizers are the primary resource for gardeners seeking a wider selection beyond common varieties. These vendors offer hundreds of cultivars, including new introductions and heirloom varieties that local shops rarely carry. While online purchases may involve shipping costs and the plants often arrive as smaller, bare-root stock, they provide access to a vast range of options.
The American Iris Society (AIS) or its local chapters frequently hold sales or auctions, often featuring divisions from members’ gardens. This is an excellent way to acquire named, high-quality varieties directly from experienced growers, often at competitive prices. Local community groups and farmers’ markets can also be a source for divisions, where local gardeners sell off their excess rhizomes, making it a budget-friendly option.
Understanding Iris Varieties and Purchase Timing
The ideal time to acquire and plant an iris is determined by whether it grows from a rhizome or a true bulb. The most recognized garden varieties, the Bearded Irises (Iris germanica), grow from thick rhizomes that store nutrients. These bare rhizomes are best bought and planted in mid-summer through early fall, typically from July to September.
The late-summer timing allows the newly planted rhizome at least six weeks to establish a robust root system before the first hard frost. If planted too late, the root growth will not be sufficient to anchor the plant or support next season’s bloom. Bearded irises are generally sold as bare rhizomes during this period, often with the foliage trimmed back to a short fan shape.
Beardless Irises
Beardless Irises, which include varieties like Siberian (Iris sibirica), Japanese (Iris ensata), and Louisiana irises, are often sold as potted plants throughout the growing season. If purchased bare-root, these rhizomes are usually planted in the fall, from August to October, and benefit from being soaked overnight before planting.
Bulbous Irises
Bulbous Irises, such as Dutch (Iris hollandica) and Reticulata (Iris reticulata), are sold as true bulbs. They must be planted in the fall alongside daffodils and tulips, before the ground freezes, for a spring bloom.
Selecting Healthy Iris Stock
A visual inspection of the planting material is necessary to ensure viability. When purchasing Bearded Iris rhizomes, they should feel firm and solid to the touch, indicating good nutrient storage. Avoid any rhizomes that have soft, mushy, or slimy spots, as these are signs of bacterial soft rot, which can be fatal to the plant.
A foul odor is another indicator of rot. Check the rhizomes for small holes or tunnels, which can be evidence of the destructive iris borer, a pest that hollows out the rhizome. For potted beardless irises, look for vibrant, green foliage free of dark spots, which may indicate fungal leaf spot.
Bulbous irises should be firm, dry, and plump, with no visible gray mold or signs of shriveling, which suggests dehydration or improper storage. If the plant material is healthy, the foliage fan on a rhizome will either be green or cleanly trimmed, and the roots, if present, should look white and fresh.