Iris Perennial Rhizomes

Irises are among the most beloved perennials, cherished for their striking flowers and elegant foliage. Two of the most popular varieties are Iris Germanica (Bearded Iris) and Iris Sibirica(Siberian Iris). While both are stunning in their own right, they differ in growth habits, flowering times, and care requirements. Whether you’re looking to add a splash of colour to your borders or create a low-maintenance garden, these irises are sure to impress.

Stephen’s Iris top picks

Stephen Teeuw is the 3rd generation of his family to work in the flower bulb industry; he grows hundreds of varieties of new bulbs each year. Here are the iris that he would recommend you consider for your garden:

• Emma Louise: There was a house on the outskirts of Cambridge that had a whole wall of these. I drove past it for years thinking one day I will do the same!

• Nibelungen: If you are looking for drama then bearded Iris are a great start. The falls of this flower are incredible.

• Snow Queen: A beautiful little Siberica iris with soft green and yellow colouring. Quite a contrast to the showy beaded iris.

Planting Instructions for Irises

• When to Plant

The best time to plant irises is in late summer or early autumn (August to October), allowing the roots to establish before winter.

• Soil Preparation

 Both varieties prefer well-draining soil. For Bearded Iris, ensure the soil is slightly alkaline, while Siberian Iris tolerates a wider pH range.

• Planting Depth

For Iris Germanica, plant the rhizomes just below the soil surface, leaving the top exposed. For Iris Sibirica, plant the roots about 5cm deep.

• Spacing

Space Bearded Iris rhizomes 30-45cm apart, and Siberian Iris clumps 45-60cm apart to allow for growth.

• Watering

Water thoroughly after planting, then keep the soil moist but not waterlogged.

Differences Between Iris Germanica and Iris Sibirica

Overwintering Irises

Both Iris Germanica and Iris Sibirica are hardy perennials that can survive UK winters with minimal care. For Bearded Iris, ensure the rhizomes are not buried too deeply, as this can lead to rot. Mulch lightly to protect from frost. Siberian Iris is more tolerant of wet conditions but benefits from a layer of mulch to insulate the roots. In spring, remove any dead foliage to encourage new growth.

Top 5 Questions About Irises

1. Do irises need full sun?
   Yes, both Iris Germanica and Iris Sibirica thrive in full sun, though Siberian Iris can tolerate partial shade.

2. How often should I divide irises?
   Bearded Iris should be divided every 3-5 years to prevent overcrowding. Siberian Iris can go longer, typically every 5-10 years.

3. Why are my irises not flowering?
   Lack of sunlight, overcrowding, or planting too deeply are common causes. Ensure proper spacing and sunlight for optimal blooms.

4. Are irises deer-resistant?
   Yes, both varieties are generally deer-resistant, making them a great choice for gardens in rural areas.

5. Can irises grow in pots?
   Yes, especially Bearded Iris. Use well-draining soil and ensure the pot is large enough to accommodate the rhizomes.

Why you should order your Iris from Peter Nyssen

•  We are a friendly, family run business with more than 60 years experience

•  We offer bulk prices and free delivery for orders over £50

•  We supply flower bulbs in quantities large and small, for all types of gardener from the cottage potterer through to the professional landscaper.

With the right planting time and location, these stunning flowers will thrive and add colour and interest to your outdoor space. So why not give them a try in your own garden? For help and advice, call our team on 0161 747 4000. For guidance on how to get the best from your iris plants