In preparing the iris, first, you need to make sure that the iris you are planting is appropriate for weather conditions, deadhead your iris every few weeks, cut down any diseased or damaged plants, place a layer of mulch, water sparingly, fertilize only when necessary, and mulch again in the spring to help keep the soil warm and moist.
Iris is one of the favorite flowers among gardeners because they are easy to grow and maintain. However, with their popularity comes the challenge of knowing how to prepare iris for winter. Here, we will provide you with a guide on properly caring for the iris to survive freezing during the winter season. We will also share some tips on keeping the iris healthy and vibrant all year round!
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Selecting Daylily Varieties
Flowers and winter growth habits are characteristics of perennial daylilies (Hemerocallis spp.). However, the best way to ensure minimal winter chores is to grow daylily varieties appropriate for your area’s weather conditions.
Daylily cultivars that grow well in your area are usually available at local nurseries, but you should be cautious if you order them online. Winter chores differ for dormant, semi-evergreen, and evergreen plants.
Dormant daylilies can be grown in USDA plant hardiness zones 3-9, and semi-evergreen daylilies can be grown in USDA zones 5-11. Evergreen daylilies do well in USDA zones 8 through 11, but they struggle in colder climates.
Taking Care of a Dormant Daylily in the Winter
At the first fall freeze, the foliage on dormant daylilies rapidly deteriorates. Since they can’t survive without winter rest, they tend to wane in areas where it doesn’t get cold enough to keep them healthy.
Winter ice and dehydration do not penetrate their bullet-shaped buds as they rest dormant below the surface. It is only in the spring when they emerge from the ground in spear-like shoots that they have any foliage above the ground.
Cut back dormant daylilies to within a few inches of the ground in the fall after they have turned brown, using pruning shears. Alternatively, you can simply pull the foliage away from the plant’s crown in the spring when it is still in place. Pruning tools can be cleaned by soaking them in a solution of one part household bleach to three parts water for five minutes, then letting them air dry.
Non-perennial and Perennial Care for the Winter
In warmer climates, semi-evergreen daylilies’ foliage remains green. Semi-evergreen trees in colder climates lose their leaves early in the winter due to successive autumn freezes. If they go dormant, they will remain as short sprouts that will grow quickly in the spring. Around dormant semi-evergreen daylilies, remove decayed or dead leaves, but leave the sprouts alone.
Even though their growth slows in the winter, evergreen daylilies remain green all year round. Their foliage will turn to mush if the temperature drops below freezing. Winter is a good time to clean up any decayed or damaged foliage on your evergreen lilies.
It’s important to cover daylilies with a 2-inch layer of mulch to keep weeds at bay and mitigate the effects of freezing and thawing in winter. Replace the mulch every year as it decomposes.
Dormant and dormant semi-evergreen plants that emerge in the spring may have distorted foliage due to the winter cold, known as “spring sickness.” This damaged foliage will return to full health as the weather warms up.
Winter Dormant and Semi-Evergreen
Whether they are dormant, deciduous, or evergreen, daylilies and bearded iris go dormant in cold places, even if they are evergreen. They can’t grow at this time of year because it’s too cold. They lose their desire and ability to grow and flower. Even though evergreen daylilies have all their leaves, they stay dormant in cold climates. Winter in Australia gives the daylilies that well-earned break. For some reason, daylilies aren’t called deciduous plants. They lose their leaves, but this isn’t true for some reason.
In warmer climates, daylilies have that extra growing time over cold climates, where the daylily and bearded iris keep growing during their warm winter months. However, the bearded iris might not bloom.
When the bearded iris is dormant, its leaves are shorter in the winter.
Iris roots are well-protected by mulch, one of the simplest and most effective methods available. Whether newly planted or well-established, the roots of irises are best protected by a thick layer of mulch. The University of Minnesota Extension recommends using pine needles, straw, leaves, compost, or even additional soil from the garden to create a 4- to 6-inch layer of mulch around the base of the plant. It is best to remove some mulch from around the newly planted plants in spring when the snow begins to thaw and remove all of the mulch from the rest of the garden when it has dried out.
Divide established irises in midsummer, four to six weeks after the last blooms have faded, if necessary. According to the North Carolina State University Extension, plants need time to establish a root system before winter. Those irises are likely to produce new growth before winter sets in, but their root systems cannot withstand freeze/thaw cycles that may take place in the winter and early spring. Irises that have just been divided should be mulched in the late autumn.
Freezing and Thawing Periods
Overwintering bulbs and tubers can be damaged by freeze/thaw cycles. Bulbs and tubers—irises included—are toppled from their beds during these cycles, which cause the ground to thaw briefly before freezing again. Because they won’t be able to withstand such conditions, a thick layer of mulch will serve as a safeguard.