Whether you need to cover roses winter depends on your climate zone and rose type. Gardeners in zones 5 and colder with grafted roses like hybrid teas need winter protection. Own-root shrub roses and those in zones 7 and warmer often skip covering.
Winter protection roses need varies based on how they grow. I garden in zone 5 and learned this lesson the hard way. My grafted hybrid teas died back to the ground without protection. Meanwhile, my shrub roses came through fine with just a layer of mulch.
In my experience, the difference comes down to the bud union on grafted roses. This is the swollen knob where the fancy variety was joined to a tough rootstock. If this graft point freezes, you lose your named rose variety. The plant may grow back, but only as the rootstock.
University of Minnesota trials showed roses can survive -35°F (-37°C) with mulch and snow. But this research used own-root shrub roses bred for cold climates. Your grafted hybrid tea can't regrow from roots if the top dies from winter cold.
The roses winter care covering process starts after several hard frosts hit your garden. Wait until the plant goes dormant. Temperatures should stay below 28°F (-2°C) at night. Covering too early traps heat and can cause new growth that will freeze later.
Mound 8-12 inches of soil or compost around the base of grafted roses. This buries and protects the bud union from cold. It also shields against freeze-thaw cycles that damage plant tissue. Some gardeners add a layer of straw or leaves on top for extra warmth.
Rose cones work for some gardeners but have drawbacks. They can heat up on sunny winter days and cause premature growth. If you use cones, cut holes in the top for air flow. Pack mulch around the base inside the cone for the best results.
Remove winter protection in spring after the last hard freeze in your area. Do this too early and a late frost can kill new growth. Start by removing the top layer first. Wait another week or two before pulling back the soil mound from around your roses.
Your own-root shrub roses rarely need covering even in cold zones. These roses can regrow from the roots if the tops die. The plant that comes back is the same variety you planted. This makes them much easier to care for in harsh winters.
Read the full article: When to Plant Roses for Beautiful Blooms
