As long as a rhododendron presents itself in a magnificent flower robe, the gardener rightly doesn't waste a thought on the cut. With increasing age, the ornamental shrub visibly wilts and is only a shadow of itself. You should note a pruning in the care plan by now at the latest. When and how to skilfully prune a rhododendron bush, this tutorial explains in detail.

Clean, sharp tools should always be used for cutting

Table of Contents

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  1. cutting occasions
  2. flower care
  3. maintenance cut
  4. taper cut
  5. Reconstructive cut after taper
  6. frequently asked Questions

    7. Reasons for a rhododendron pruning - occasions in a nutshell

    Rhododendron experts are largely in agreement about the beginning of pruning care. In the first few years you should let the picturesque flowering shrub do its thing. The opulent ornamental tree develops an inimitable habit with a stable framework and compact stature. The colorful flower clusters unfold every spring from the buds that were planted the previous year.

    Planting and training cuts are to be deleted on the rhododendron without replacement. Apart from summer flower care, a rhododendron does not require pruning in the first few years. Only when the balanced growth starts to falter with increasing age can optical disruptive factors be the reason for a pruning measure. The following table summarizes what these are, what the goal is and what point in time is advantageous:

    cut type objective Appointment recommendation
    clean up remove wilted flowers, encourage new buds after flowering
    maintenance cut remove bare and unfavorable individual shoots in spring before flowering
    taper cut revitalize old shrub in late winter until March 1st
    Reconstructive cut after taper Promote new growth after radical pruning in spring before flowering

    For all dwarf rhododendrons (Rhododendron repens), the only thing that matters is flower care. Popular varieties such as 'Pumuckl' remain comparatively small and compact with a growth height of 50 centimetres. This does not change even after many years, so you do not have to think about a maintenance or rejuvenation cut. Regular cleaning of withered inflorescences rewards the little beauties with a dense flower dress that covers the green leaves.

    Blossom care on the rhododendron - mock cut without scissors

    There are two convincing arguments in favor of annual flower care: a rhododendron that has withered is really no feast for the eyes. In addition, the buds for the next shoot are already underneath the faded flowers. Secateurs are not required for the care measure. How to clean wilted rhododendron flowers by hand:

    • Hold the small piece of shoot under the withered inflorescence with your index finger and thumb
    • Pinch off the flower clusters or break them off to one side

    The sooner you devote yourself to cleaning, the easier it will be. Keep an eye on the new buds and fresh shoots below the faded flowers. At this early stage of growth, the plant parts are delicate and break off easily.

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    Remove water shoots promptly

    For the removal of naughty water shooters, the fastest appointment is the best appointment. This designation refers to branches pointing steeply upwards from the wild undergrowth. The most beautiful rhododendron varieties are the product of horticultural refinement. A noble part is grafted with a lot of dexterity on a robust wild base. Strong-growing shoots regularly sprout from the wild base in order to overgrow the precious part and compete for nutrients. Wild shoots are revealed by the distinctively large leaf spacings, the internodes. If you catch a water shooter, cut or tear off the shoot immediately.

    Maintenance pruning focuses on single shoots

    Sometimes bare branches protrude from a rhododendron and disturb the well-groomed appearance. These shoots are a case for maintenance pruning. If you are concerned that the pruning is not visible at first glance, we recommend this cutting technique:

    • The best time is before the flowering period begins
    • Examine the shoot in question for a lower-lying, young, unbranched shoot
    • Start the cut at the fork of the branch and side branch
    • Leave small cone of 5 centimeters with side leaf

    The incision is a combination of a lead incision and a tenon incision. With this strategy, you can reliably prevent unsightly gaps and optimize the chances of new sprouting at this point. The figure below explains the procedure. On the other hand, if you haphazardly saw off a cheeky branch somewhere, you will look in vain for young shoots and have to live with a large hole in the foliage for many years.

    If individual branches protrude cheekily and bare from the rhododendron, a diversion cut brings the shoots to their senses. Shorten the unfavorable shoot so that a young, short side shoot takes over the new leadership position. Small cones with leaves promote new growth because the supply of nutrients is not interrupted.

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    The cutting technique "on cones" makes tired rhododendrons perk up

    In cutting instructions for rhododendrons, there is regular talk of a sophisticated cutting technique that is crucial for the result. For this reason, we will deepen the procedure at this point. Rhododendrons rarely sprout again from old wood. By leaving a small cone with a leaf, shoot or dormant eye when cutting, you stimulate growth. The plant parts mentioned maintain the nutrient supply, so that the shrub continues to grow at this point. Always cut on the leafy shoot "on cones" with a lateral, outward-facing blade. On the bare branch, place the scissors 5 centimeters behind a fork to the younger side shoot. Where both are lacking, look for or feel a sleeping eye under the bark and apply your newly acquired know-how here. Then practice patience. It can take more than a year for budding to get going.

    Rejuvenation cut reverses aging - it succeeds in stages

    If the ravages of time gnaw at a rhododendron, you are not powerless in the face of gradual balding. Spread over several years, you can rejuvenate the old, aging shrub. Please don't be tempted to put the sparse, bare ornamental tree on the stick in one go. In this case, total failure is inevitable. It is better if you follow the instructions in this tutorial. How to do it right:

    • The best time is on a frost-free day before March 1st
    • Important: According to the Federal Nature Conservation Act, do not carry out rejuvenation cuts between March 1st and October 30th
    • A third of the bare shoots derive from a young side shoot
    • Leave 5 centimeters of pegs at the cutting point behind the fork
    • Heavily aged skeleton shoots lead to the lowest standing side shoot near the ground

    The image below illustrates the first stage on the road to rejuvenation. Then fertilize the cut rhododendron generously with leaf compost and horn shavings (32.93€) or special rhododendron fertilizer with an NPK formulation of 14+7+14. A year of waiting follows before the procedure continues as a combination of build-up and rejuvenation cut. You can read about how to do this in the following section.

    In the first stage of regeneration, remove a maximum of one third of all shoots or direct them to a lower-lying side shoot. Again, leave 5 centimeters of small cones.

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    Proper cutting tool is crucial

    Rhododendron pruning becomes a horticultural success story when the right tool is used. As basic equipment for uninterrupted work, the appropriate scissors or saw should be ready for every type of cut and drive strength. The one-hand secateurs are suitable for shoots up to 2 centimeters thick, with either a bypass or anvil mechanism. Branches with a diameter of 2 to 4 centimeters can be mastered with two-hand pruning shears or a folding saw. (€17.70) For a thinning cut on the majestic shrub with branches of 4 centimeters in diameter and more, a high-quality sword or hacksaw is a must.

    A build-up cut completes the rejuvenation - this is how it works

    Under ideal conditions, the first cones will sprout in summer after a rejuvenation. As the cone grows, the remains of the cones dry up and can be easily removed. The following spring, prune the next third of overaged branches, again using combined deflection and tenon pruning. The figure below shows the correct procedure.

    Take this opportunity to examine all young ground shoots. Select the strongest specimens and cut off weak competitive shoots to ground level.

    If no cones are expelled, postpone the second stage of regeneration by another year. Failure of young shoots to grow indicates that your rhododendron is still suffering from the hardships of the first stage. By refraining from further pruning measures, you give the shrub the opportunity to gather its strength.

    If the first young shoots form at the interfaces in the year after the regeneration, the next third of the old shoots are regenerated. Without a fresh shoot, wait until next year for the next stage.

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    Closure of wounds on rhododendrons is no longer up-to-date - with one exception

    Thinning out old, thick branches or a comprehensive rejuvenation cut leave extensive cuts on the rhododendron. Modern home gardeners leave the healing process to the shrub and no longer seal the wounds with tree wax.(12.96€) The latest scientific research has shown that there is dividing tissue under the bark in every tree and shrub - the cambium. After wounds, cambium forms woundwood to overwhelm the damaged area. This natural form of regeneration trumps gardening measures by far. Consequently, tree wax and other wound closure materials are being phased out in the home garden. The only exception is a thin layer of tree wax along the edges of the wound when frost could damage the valuable cambium.

    frequently asked Questions

    What is the difference between Rhododendron and Azalea?

    The Rhododendron genus includes more than 1000 species, including azaleas. For this reason, the popular Japanese azalea is referred to by botanists as Rhododendron japonicum. Regardless of the close botanical relationship, you can tell the two flowering shrubs apart by looking at them. A rhododendron thrives as an evergreen, mostly sprawling shrub. Azaleas, on the other hand, shed their leaves in autumn or winter and develop an upright, less expansive stature.

    Are Rhododendron Shrubs Poisonous?

    Most rhododendron species and cultivars contain a cocktail of various toxins. Not only the leaves are a health hazard, but also roots, buds, flowers and fruits. Excessive consumption causes severe symptoms of poisoning in humans and animals, ranging from nausea and vomiting to shortness of breath and slowed heart activity. Please only integrate a rhododendron into the garden design if the plant is out of the reach of children and animals. Wear gloves to protect yourself when cutting. Do not dispose of clippings in the compost or in a pasture, but in the organic waste bin.

    Can I use clippings to propagate cuttings?

    The propagation of rhododendrons with cuttings is considered a challenge even among plant experts. Tree nurseries usually propagate the ornamental tree by grafting. Instead of bothering with these complicated methods, we recommend the sinker method. Semi-lignified shoots close to the ground are perfect. First, remove all side shoots and lightly score the fabric on the underside. Bury the drive piece with the wounded area in the ground. Fix the end of the shoot to a wooden stick. Mother plant and offshoot remain connected to each other until the offspring has developed its own root system.

    Rhododendron buds are dying - what to do?

    You describe the typical symptom of a fungal infection triggered by the rhododendron leafhopper. When they lay their eggs, the insects cause tiny wounds on the bud that fungal pathogens use as entry points. Remove dead flower buds promptly and dispose of them with household waste. To prevent this from happening in the first place, you can prevent the female cicadas from laying eggs in August and September with yellow boards.

    The 3 most common cutting mistakes

    No master rhododendron pruning has yet fallen from the sky. Although the beautiful flowering shrubs are easy to care for per se, pruning requires attention to the special growth characteristics. The following table would like to arm you for the three most common pruning mistakes with tips for prevention.

    cutting error damage picture prevention
    withered flowers not trimmed declining abundance of flowers withered flowers break out promptly
    aged rhododendron placed on the stick total failure rejuvenate old shrub in stages
    not pruned back to cones no new shoots at the interface Always cut branches with a small spigot and lateral leaf or shoot
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    tips

    Transplanting rhododendrons requires a rethink of pruning. While pruning is part of the standard procedure for other garden shrubs, the measure for rhododendrons is canceled without replacement. The sap pressure is simply too low to sprout again after a change of location and pruning. Therefore, give a transplanted rhododendron special attention when watering and fertilizing so that it can compensate for the lost root volume on its own.

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Vegetable garden