Opening the Rose Garden by Diane Brueckman
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id-April is the safest time to start uncovering your winter protected roses. Look for leaf buds swelling on the canes exposed above the mulch. Do not despair if you a see lot of black canes with no obvious new growth. The severe cold in February killed many canes down to the mulch but you will find growth below the mulch. When I get ready to open up my garden, I start with the hardiest roses, usually my shrubs, and prune them first. The last roses Pruned and properly “stressed” canes of a climbing rose at Missouri Botanical Garden. I work on are the hybrid teas. I thin out the main canes of climbers to the best three or four and take out the oldest canes and any damaged canes. Main canes (those coming from the bud-union) should not be cut but bend them along their support, either a trellis or fence. Once you determine which canes you are keeping prune the lateral canes (those coming off the main canes) to 3 or 4 bud eyes. Stressing the main canes along the support will encourage the side shoots to produce blooms. If the canes are allowed to grow straight up you will only have blooms on the ends of the canes. Tie the canes securely to their support. Shrubs such as Knock Out roses can be pruned in March but it is not too late to prune them now. Take out old growth especially if it is crossing through the center of the plant. I know some shrubs are sold as no maintenance but all plants benefit from a yearly cleaning up. Air circulation is improved and the overall appearance of the plant is much better. The once blooming Old Garden Roses should not be pruned until after they bloom. If you had some die back over the winter you can cut that out of the bush but otherwise wait until after they 18
bloom before pruning. After they bloom only cut back 1/3 of the height. When you start on the modern roses, do the hardiest first. Ownroot roses have fewer problems with winter kill than the budded roses, but the method is the same if they were covered. I have had some die back to the ground but they almost always come back because the roots are true to the rose you planted. I watch them for a few weeks and low and behold they start to come up. The lesson here is do not dig them up right away.
Budded roses are a different story, if the bud-union dies the rootstock will produce a different rose most likely ‘Dr. Huey’ a pretty red rose but not what you planted. Carefully pull the mulch away from the bud-union. Prune out any crossing canes as well as canes that are diseased or damaged. Leave some excess mulch piled near the roses in case of a late freeze so you can quickly recover the bud-unions and basil shoots (the new canes coming directly from the bud-union). New growth especially basil shoots are very susceptible to extreme cold when exposed to cold before they harden off. After everything is uncovered, it is time to fertilize the roses. I use strictly organic fertilizer. I like the idea of feeding the soil as well as the plants. Using organic matter keeps the pH of the soil well in the range roses like (a pH of 6.3 to 6.8 is ideal but 6 – 7 also works). My mulch is once ground tree trimmings which contain brown and green material. The tree services are happy to dump their trimmings in my yard. If I have more than I can use, I let it compost for a year. There are also many organic fertilizers on the market to choose from. The final step to opening the garden is to spray with a fungicide. As the weather heats up and the humidity increases it is best to get the fungus before it gets you. The first disease in spring is powdery mildew, a neem oil spray will knock it out. Neem oil also helps with blackspot. Diane Brueckman is a retired rosarian with Missouri Botanical Garden, and currently owns Rosey Acres in Baldwin, Illinois. You can reach her at (618) 785-3011 or droseyacres@ egyptian.net.
The Gateway Gardener™ APRIL 2022
