Though most shrub roses are hardy in Kansas, other types of roses can be more tender. For example, the hybrid teas have certain species in their ancestry that had their origin in the warm climate of southern China. These roses need protection to reliably survive our winters.
A mound of soil or compost about 8 to 10 inches high should be hilled around each plant after most of the leaves have dropped. If soil is used, it should be brought in from another part of the garden. Do not pull soil from between plants to make the mound as this can either directly damage the roots of the rose or make the roots more susceptible to cold damage. This should be done about Thanksgiving time.
After the ground has frozen, a mulch made up of straw, leaves, or hay should be added to an additional depth of 4 inches to provide further protection. Some additional soil may then be placed on top of the mulch to keep it in place. Do not add the mulch before the ground freezes or mice may invade and feed on the roses over the winter. The purpose of these coverings is not only to moderate the cold but also to prevent warm days during the winter or early spring from stimulating growth which is very tender to renewed cold weather.
Excessively tall canes should be pruned down to a height of 36 inches and tied together to prevent them from being whipped by strong winter winds. This whipping action can damage the crown of the plant or loosen the soil surrounding it.
Next spring, the coverings need to be removed before new growth starts. Do not do this before the ground thaws as the tops may begin growth before the roots can provide water.
-- The Garden Calendar is sponsored by K-State Research and Extension-Douglas County office and written this week by Dennis Bejot, county extension director. For more information call the extension office, 843-7058, between 8 a.m. and 5 p.m., Monday-Friday.