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Spring Rose Pruning

With roses blooming so beautifully around town right now, we know that roses must be on people’s minds when they come to the garden center!

One reason gardeners sometimes shy away from having roses in their garden is that they’ve heard spring pruning is daunting. Not so! We would like to share the following article written by Dave Ingram, explaining the ins and outs of spring rose pruning.

Spring Rose Pruning

By Dave Ingram, American Rose Society Master Rosarian

Spring pruning of roses can produce a lot of uncertainty for gardeners. Where do I cut? When? In truth, you can learn to be comfortable with what is actually a pretty basic process. My first tip? Study what your rose is telling you as it begins to grow in the spring. The poor thing has had a long, hard winter outside in the garden, while you got to stay nice and warm inside.

The idea behind pruning roses is to cut your stems to produce new growth that enhances your rose’s blooming power. In general, rosarians along the Front Range like to do their first pruning around last frost. Most years, that date falls roughly between May 1 and Mother’s Day. If you prune earlier, you may encourage lush new growth that gets damaged by a late frost (and then you have to prune again). Prune much later and the new growth can mask the damaged canes that need to be removed. It’s normal to fertilize your roses for the first time when you do your spring pruning. The whole idea of spring pruning and first fertilizing is to encourage your roses to grow when it is safe to do so.

The first rule of pruning is to understand that when you cut into living rose tissue, you send a signal to your rose to grow back. So: Pruning Stimulates Growth. New growth rejuvenates the plant and gives you more flowers.

The second rule is to understand that some groups of roses, such as Hybrid Teas, Grandifloras and Floribunda (the most popular classes; if you are reading this, I bet you have some in your garden) have a normal tendency for the above-ground growth to suffer severe die-back in our long winters. It ain’t you; it’s the genetics of the rose. I call these the semi-hardy roses. With some roses, it is normal to cut them back near the ground every year.

The third rule of rose pruning in the spring is to remove all Dead, Diseased, and Damaged growth. With the more winter-hardy varieties, you may find a few inches of dead tip, then some wimpy new growth behind it, and further back on the cane, more robust growth that indicates healthy stems that can support good growth and lavish flowering. I prune to this robust growth; wimpy doesn’t work for me. Does all the new growth seem to be proportional and healthy? Well, lucky you. You can leave that rose alone, if you want. Fertilize and move on to the next one.

By far the most common roses in nurseries and our gardens are genetically inclined to suffer cane damage in our long winters. A semi-hardy rose survives, but loses most or all of its above ground growth. Even in non-freezing Southern California, the rule is to cut semi-hardy Hybrid Tea canes back to around a foot above the ground (new growth = best flowers). In Colorado, Jack Frost may decide to claim the entire cane. The key is to look for healthy new growth sprouting from the base of the plant. Once you see this, you can afford to be tough on the remaining above ground canes. Healthy cane pith is green on the outside and like a Granny Smith apple inside (in other words, able to easily pass water and nutrients). If you find any growth like this, you can stop pruning there. Mostly, you will find damaged canes that are green on the outside but have pith inside like dead cardboard. Imagine: you are drinking lemonade through a straw on a brutal, hot summer day. If the straw gets clogged with lemon pulp, it gets really hard to drink. Semi-hardy rose canes get clogged with dead cells. Even if the cane is trying to send out wimpy new growth above a blotchy, blackened section, that growth will not be healthy, rarely re-flowers and is prone to insect munching and fungal diseases. Be brave, cut that stuff out. Keep searching for good pith, all the way to the ground if necessary. Leave only the growth that is new and healthy, even if it is sprouting from below ground. You will be amazed at how fast your rose will rebound with new growth that shoots for the sky and flowers on schedule in early June.

Miniatures are often fairly hardy. Remove any dead growth, then prune back to the places where the plant is growing most actively. The popular Knock Out® shrubs are treated the same. Each winter will be a little different. Climbers should have dead and badly damaged growth removed, and any loose canes secured. Training canes horizontally (or arching them on a trellis) will produce more flowering growth along the canes.
Enjoy the new rose season!

Some extra tips:
1. Update your tetanus shot.

2. With any stems pruned within a foot of the ground, seal the cane ends with waterproof wood glue such as Elmer’s or Titebond II; or you can use colored nail polish. There are beneficial insects that drill into pruning cuts to build their nests. You want to keep them out of the heart of the plant underground.

3. Remember: it is really hard to kill a rose by pruning it. Pruning just stimulates new growth. Be brave – go for it. Canes are like hair – they grow back. Let the way your rose grows back guide your approach in future years.

4. The more you learn about good culture (such as healthy soil, proper fertilizing, consistent watering, a winter mound of mulch for semi-hardy roses from December to late April), the better your rose will rebound in spring, and the simpler pruning becomes. Culture and pruning go hand in hand. The Queen of Flowers is ready if you are!

5. Questions? Ask your nursery staff for help, or go to
denverrosesociety.org to find a list of Consulting Rosarians who offer free rose growing advice by email or phone.

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