Pruning large rhododendrons can seem like an overwhelming undertaking, but it doesn’t need to be. This will mean that in years to come - just as the shrub is reaching its full glory, there will be a need to take drastic action by way of cutting down hard. Now what? Rejuvenation pruning. – Multnomah County. Pay special attention to watering. Registration on or use of this site constitutes acceptance of our User Agreement, Privacy Policy and Cookie Statement, and Your California Privacy Rights (each updated 1/1/20). Mark Graves/The Oregonian/OregonliveLC- Mark Graves. A: Rhododendrons are impressive plants in a landscape. Many rhododendron spe-cies and hybrids can be severely pruned and come back as good as new. Pruning is spread over two or three years to gauge response or maintain the natural shape. Remember! Rejuvenation pruning calls for dras-tic cuts on old wood Rejuvenation pruning is best used to restore shrubs that have become leggy, overgrown, or otherwise unattractive. – Anne Schmidt, OSU Extension Master Gardener, Q: I have a small water garden and I need to safely dispose of excess salvinia, frogbit and water hyacinth. It's best to remove only 25-30 percent of the leaves in a year, as hard pruning will stimulate the plant to put out vigorous, messy growth. This makes neat little mounds of twigs that will explode with new growth come spring. Rejuvenation pruning, also called renewal pruning, involves cutting some types of shrubs almost down to the ground, leaving only 6 to 24 inches. Bravely make big cuts if rejuvenation is required. Most rhododendrons respond well to pruning. That's it. james@properlandscaping.com It would be very unfortunate to get any of these plants into our streams and wetlands. It is important to remove the flower stems from the shrub once blooming has stopped. But what if your rhodo is too big? Rejuvenation Pruning for Azaleas and Rhododendrons. Subscribe to OregonLive. Staggered renovation. The seeds would probably survive composting. The main goal of rejuvenation pruning is height reduction, and in many cases, plants may be reduced in height by 75 to 90 percent. Mock orange. This rejuvenation pruning was done at a corner unit where there was a problem with vehicle sight lines. Latent buds in action, a cluster of four buds below the cut. That's it. Q: I love our deep red rhododendron, but it has grown so big that it blocks our front window completely. I'd rather keep the rhododendron but in a much smaller version, and I'm willing to forgo blooms for a year or two to do so. I have considered setting them out to dry prior to composting but wonder if the seeds would still be viable. Here are some questions asked by other gardeners. There are three pruning actions associated with rhododendrons. This was the result. Done every three to five years, this extreme method of pruning can indeed rejuvenate an overgrown or misshapen shrub, just as the name implies. – Anne Schmidt, OSU Extension Master Gardener, Dahlia breed: Scott's Caldera Katie Currid/The Oregonian LC-LC-, Q: I have several dahlias in my yard that grow well but have little to no bloom. Plants that respond well to rejuvenation include, forsythia, lilac, and spirea. […] I have also done renovation pruning on rhododendrons. Spiraea. Rejuvenation pruning. If you have an overgrown shrub that is no longer flowering, try rejuvenation pruning in early spring by cutting all the stems back to the ground. Plants that respond well to rejuvenation include, forsythia, lilac, and spirea. Salvinia (Salvinia minima) is listed as “Quarantine” by the U.S. Department of Agriculture, Noxious and Invasive Plants in Oregon. 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