Don’t prune into old wood. This is the key step to developing the dense bushy plant that you are after. Any severe pruning of these plants should be done in March or April. Some gardeners rejuvenate rhododendron shrubs by cutting back only one-third of all branches in each of three subsequent years. These plants often send out a single long new shoots with no branching. Severe pruning of rhododendron is done to correct years of neglect that has led to overgrowth and leggy flowers. Because severe pruning prevents flowering the following year, you don't have to worry about preserving the flower buds, and it's best to prune as early as possible. First, the ideal time to do undertake rejuvenation pruning is not after flowering (that’s when you do light pruning), but rather early in the spring, before the start of the growing season. Maintenance pruning is the removal of spent flowers and old, dead wood. Severe pruning may result in growth from below the scion, which should be removed. have an attractive, natural shape that may lead you to believe they don't need regular pruning. If you find only living tissue low to the ground I would most likely replace the plants. Maintenance pruning is the removal of spent flowers and old, dead wood. Rhododendron pruning usually is conducted immediately after the flowering season ends, but no later than mid-June. In the second year after the harsh pruning, many more branch tips will produce flower trusses and by the third year, the shrub should be full and lush, producing numerous and widespread flowers all over. The final thing you want to do is to pinch or snap off the new growth back when it’s a couple of inches long. The 1 st thing you want to do is prune any branches that are sticking out of the outline profile of the plant. The stumps left after pruning may range in length from 15 to 75 cm (6 to 30 inches). Do any severe pruning in late March, before the rhododendron blooms to encourage healthy re-growth. Throughout the growing season, help the rhododendron bush by plucking spent flowers and clipping back errant branches that are overreaching into windows or over surrounding trees or bushes. Weak or sickly plants are best replaced. First, the ideal time to do undertake rejuvenation pruning is not after flowering (that’s when you do light pruning), but rather early in the spring, before the start of the growing season. On the other hand, if your rhododendron is more than 3 years old, a severe pruning back to within a few inches of the ground will tend to revitalize it, shooting new branches loaded with buds outward once more. If a rhododendron is not in too much shade, it can be cut back severely and will come back from the base. How to Deadhead Rhododendrons … rhododendrons are a group of hybrid culitvar shrubs created by breeding Rhododendron carolinianum with R. dauricum var. Arborvitae, as well as juniper, develops a dead zone in the center of the plant. As long as an old, leggy rhododendron is not weakened by a disease, it tolerates and responds very well to a severe pruning, more commonly called a rejuvenation pruning by horticulturists. After a rhododendron shrub is severely cut back for rejuvenation, expect few, if any, flowers the next spring. Rhododendrons are slow to recover from severe pruning. These plants should be pruned in late spring, after they have flowered. Mulch helps keep the moisture level steady. Rejuvenation pruning is best used to restore shrubs that have become leggy, overgrown, or otherwise unattractive. Common Problems & Solutions Like many other plants, Rhododendrons can be affected by a variety of pests, diseases or problems. Rhododendron in bloom. Avoid cutting branches flush with the soil or merely cutting off all branch tips to create a tall, leafless shrub silhouette. Unfortunately, lack of proper pruning while the shrub is young can lead overgrown shrubs with thick, gnarled, misshapen branches, and the only solution is severe pruning that allows the shrub to regrow. Their adventitious buds at the base of the plant will send up new shoots, but keep in mind that flowering usually will not occur for up to two or three years after this heavy pruning. This is a quick method and plants don't always survive such severe pruning. A severely pruned rhododendron is susceptible to insect and disease problems. There are evergreen and deciduous forms of both. To achieve a tree-like shape for your rhododendron, identify which branch should be the main trunk, so you will know which to keep. Many rhododendron species and hybrids can be … This allows the plant to focus energy on the remaining shoots, and to let air and light evenly surround each newly growing branch. Watering potted rhododendron In the spring, cut off any dead or damaged branches to encourage new growth. Rhododendrons can tolerate severe pruning at any time of year as long as you are willing to wait a year or two for them to re-flower. which may have interacted with the pruning itself. Severe pruning is not uncommon with rhododendrons and azaleas. I plan on doing some rejuvenation pruning and cutting it back so it is only about 6 feet tall. A healthy plant can be cut to the ground and will usually come back. In early spring, cut off the oldest (no more than 1/3) of the branches down to the crown of the plant. Refrain from pruning in the fall … Once the dormant buds on the rhododendron stumps flush out new leafy twigs, evaluate the quality of the growth and thin them out. Rhododendrons which you should not prune As a rough rule, varieties with a smooth bark such as R. thomsonii, R. barbatum as well as most of the large-leaved species such as R. sinogrande are reluctant to respond to being cut back to the trunk. Initially, they make look a bit of an eye sore with bare wood but fairly soon the Rhododendron will produce fresh new growth. You can cut back woody branches into areas where no leaves or lower twigs exist. Other times risk being too early or too late. A healthy plant can be cut to the ground and will usually come back. This timing preserves the buds that already formed for next year's flowers. This eliminates any potential for flowers that year, but gives the plant the longest growing season to develop new growth and mature before the onset of autumn frosts and freezes. Both rhododendrons and azaleas tend to produce twiggy growth in the areas closest to the center of the plant, not visible from afar. Rhododendrons can also be cut back to within 6 to 8 inches of the ground if need be as in rejuvenation pruning. When severe pruning your rhododendron, it is important to remember to be patient. Rejuvenation Pruning: As rhododendrons age they lose leaves and often become open and very leggy. It may be salvaged. The disadvantages of this type of pruning are that not all shrubs tolerate drastic cutting, and, until the plant regrows, you are left with an unsightly stub. If you’re in doubt, don’t cut the entire shrub back. Rhododendrons can be pruned at any time during the year without harming the plant, but there are times that are better for pruning. Therefore, the best time to prune Rhododendrons is immediately after they flower. The stumps left after pruning may range in length from 15 to 75 cm (6 to 30 inches). When pruning is done either on the tip or the sides, cuts should not be made into the dead zone. Tall, leggy plants should be replaced with smaller varieties or plants having a low, mounding growth habit. Overgrown arborvitae cannot be pruned back more than 20 percent. Drastic pruning can also be called rejuvenation pruning. Shape Pruning: Pruning for shape enhances the rhododendrons form and habit. As with any plant, dead wood can be cut away at any time. A rhododendron shrub needs extra care for the first year or two after severe pruning. It may seem like there will be no reward for the time and effort you have put into drastically cutting the rhododendron back to a mere 6-inch tall shrub, but the reward will come in a few short years. Severe pruning means that you cut the entire rhododendron down to the primary branches of the shrub, as low as 6 inches off the ground, if possible. Photo: Pixabay ... Plants can be pruned back severely if needed since dormant lateral buds will initiate new growth after pruning. Keep the soil evenly moist but not wet or soggy. Prune back the end buds of new sprouts. Photo: Pixabay. If your large rhododendron is growing out of control and starting to look like a mess, you’ve got some pruning to do. Remove dead wood regularly. It isn't necessary to cut the shrub back to a stub if you can remove the problem while leaving the scaffolding branches. They generally grow in U.S. Department of Agriculture plant hardiness zones 5 through 9. Prune right after the blooming has finished during the summer months of June and July. Pruning a rhododendron is normally done for maintenance, shaping, and rejuvenation. Another more severe type of rejuvenation pruning involves cutting the main branches (trunks) to a point 6 inches or so above the ground. Pruning them too early will interfere with the budding for this season and pruning them too late will interfere with the next season. On the other hand, if your rhododendron is more than 3 years old, a severe pruning back to within a few inches of the ground will tend to revitalize it, shooting new branches loaded with buds outward once more. have an attractive, natural shape that may lead you to believe they don't need regular pruning. Protect exposed plants in cold climates by driving four stakes around the shrub and wrapping burlap around the stakes to buffer the drying winds. PRUNING Constant pruning of rhododendrons is not really necessary. Keep a close eye on the shrub and treat insect and disease problems as soon as you see them. Dead leaves will look yellow or brown, and dead branches will be crispy and snap easily. Wright holds a graduate diploma in environmental horticulture from the University of Melbourne, Australia, and a Master of Science in public horticulture from the University of Delaware. Next year, do another third, and so on. Rhododendrons (Rhododendron spp.) Key Points. In the wild our native rhododendron, R. macrophyllum, often is killed back to the ground by fire, only to sprout again from the root crown and in a few years regain full vigor. Stagger the height of each primary branch so the shrub will have a natural shape when it regrows. Severe pruning is not uncommon with rhododendrons and azaleas. However, Richard Colbert reported that such attempts at Tyler Arboretum were only successful if the plant had enough sun light. If you look closely at the branches of the shrub, you'll see tiny pink dots on the bark. It’s also a lot easier mentally, strange as that may sound. Pay special attention to watering. In severe cases, you can sometimes cut your rhododendron to within 6 inches of the ground. Many plants will recover from this drastic pruning but not all will survive. Rejuvenation pruning is best used to restore shrubs that have become leggy, overgrown, or otherwise unattractive. With age (some live 80 years) or limited light, rhododendrons can become leggy. Rhododendrons should be healthy before you prune. It is worth trying to propagate older shrubs or plants of sentimental value before heavy pruning in case they do not recover. Rhododendron before pruning. This is easy as 1-2-3, and why azaleas and rhododendrons are considered low maintenance. Before you cut back this severely, examine the shrub to make sure it looks healthy and is free of insect infestations and disease. I have a rhododendron in my front yard that is completely overgrown to the point that it is taller than the lowest point of my roof. You can cut back woody branches into areas where no leaves or lower twigs exist. It is when a more severe pruning is required, cutting back to a bare trunk, that results vary considerably. Pruning: Winter, spring and early summer-flowering evergreens such as Rhododendron and Camellia are best left unpruned except for removal of unsightly shoots and deadheading, unless some shaping is required. Step 1 - wait until the flowers die off in the spring to prune. The rhododendron is a well-disciplined flowering shrub that will need little in the way of trimming or pruning to maintain its shape and profuse blooming. Rejuvenation Pruning. Other times risk being too early or too late. Don't go overboard; just … Those in heavy … Severe pruning to either of these types of plants should be done in April, although light pruning may be done at any time of year. All rhododendrons and azaleas are members of the genus Rhododendron. The advantage of hard pruning is that the shrub rejuvenates quickly. Rhododendrons can tolerate severe pruning at any time of year as long as you are willing to wait a year or two for them to re-flower. This is a good rule of thumb for any shrub or tree that needs a severe pruning. Removal of spent flower heads is important for promoting next years bloom as well as a good overall shape. By pruning just above viable dormant buds, new healthy growth can be directed to obtain a more desirable shape. Thats sound advice from Ron, excercise caution as some rhodos will never recover from a severe pruning. Step 3 - prune off live stems and branches to conform the plant into your preferred shape Hard pruning involves cutting the shrub off to a height of 6 to 12 inches (15 to 30.5 cm.) Severe pruning may result in growth from below the scion, which should be removed. If the rhododendron is large and overgrown or already looks unattractive and flowers poorly, it's best to severely prune the plant in early spring. 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