Winter Iris Garden Care
In the Northern Hemisphere the Iris are dormant beginning in November and on through February, in many areas well into March even.
Remove all spent bloom stalks and dead foliage. Trim Iris foliage to a height of about 6 inches. A clean garden will help prevent the spread of various fungal diseases and can discourage overwintering pests from building nests.
Evergreen boughs or straw make a good winter protection for Iris, particularly in areas with especially harsh winters. Apply after freeze-up. Heaving of the soil, caused by freeze-thaw patterns, can result in the dislodging of the rhizome. Avoid mulches that will trap moisture around the rhizome, as this environment can induce rot. Remove winter protection promptly in the early spring when new foliage begins sprouting.
If you live in area with mild winters, no winter protection is necessary. Keep the Iris garden free of weeds and grass throughout the winter.
Spring is inevitable no matter how high the snow banks or how low the mercury. When all threat of frost has passed, remove the winter protection. If the garden is still covered in snow and ice, leave winter protection in place. If the ground is clear of snow and ice, you may see weeds and grass begin to emerge. Get them while they're young, and before their roots become long and difficult to remove.