How to cut rhododendrons correctly - tutorial for masterful cutting

How to cut rhododendrons correctly - tutorial for masterful cutting

Reasons for a Rhododendron Cut - Occasions in Brief

There is broad agreement among rhododendron experts about the start of pruning. In the first few years, you should let the picturesque flowering shrub do it. The opulent ornamental wood develops an inimitable habit with a stable frame and compact stature. You unfold the colorful flower clusters every spring from the buds that were planted the previous year.

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Plant and education cuts are to be deleted from the rhododendron without replacement. Apart from caring for the flowers in summer, a rhododendron does not need any pruning in the first few years. Only when the balanced growth begins to falter with increasing age, optical disruptive factors can give rise to a cutting measure. The following table summarizes which these are, which goal is targeted and which point in time is advantageous:

Cut typeGoal settingDate recommendation
Cleaning upRemove dead flowers, encourage new budsafter the flowering period
Conservation cutremove bald and unfavorable individual shootsin the spring before flowering
Taper cutrevitalize old shrubin late winter until March 1st
Construction section after taperingPromote new growth after radical cuttingin the spring before flowering

For all dwarf rhododendrons (Rhododendron repens), only flower care is important. Popular varieties such as 'Pumuckl' remain comparatively small and compact with a height of 50 centimeters. Even after many years nothing changes in this, so you don't have to think about a conservation or rejuvenation cut. Regular cleaning of wilted inflorescences will thank the little beauties with a dense flower dress that covers the green leaves.

Blossom care on the rhododendron - sham cut without scissors

Two convincing arguments speak in favor of annual flower care: When it is withered, a rhododendron is truly no feast for the eyes. In addition, the buds for the next shoot are already below the withered flowers. Secateurs are not required for the maintenance measure. How to clean withered rhododendron flowers by hand:

  • With your index finger and thumb, grasp the small branch under the withered inflorescence
  • Snap off the flower cluster or break it off to the side

The sooner you start cleaning up, the easier it will be. Keep an eye on the new buds and fresh shoots below the withered flowers. At this early stage of growth, the parts of the plant are delicate and break off quickly.


Remove water bolts promptly

The fastest appointment is the best for removing cheeky water. This designation refers to branches from the game underlay that rise steeply upwards. The most beautiful rhododendron varieties are the product of horticultural refinement. A precious part is grafted onto a sturdy game underlay with great dexterity. Strong shoots regularly sprout from the wild undergrowth to overgrow the precious part and dispute nutrients. Wild shoots reveal themselves by the strikingly large spacing between leaves, the internodes. If you come across a water shooter, cut or tear off the shoot immediately.

Conservation pruning has individual shoots in its sights

Sometimes balding branches protrude from a rhododendron and disturb the well-groomed appearance. These shoots are a case for maintenance pruning. If you want the cut back to be invisible at first glance, we recommend this cutting technique:

  • The best time is before the start of flowering
  • Examine the shoot concerned for a lower, young, unbranched shoot
  • Start the cut at the fork of the branch and side branch
  • Leave small cones of 5 centimeters with a side leaf

The incision is a combination of a lead cut and a tenon cut. With this strategy you reliably prevent unsightly gaps and optimize the prospects of a new bud at this point. The figure below illustrates the procedure. If, on the other hand, you saw a cheeky branch haphazardly somewhere, you will look in vain for young shoots and have to live with a large hole in the foliage for many years.

Cut rhododendron


Cutting technique “on tenons” perks up tired rhododendrons

In cutting instructions for rhododendrons, there is regularly talk of a sophisticated cutting technique, which is decisive for the result. For this reason, we will deepen the procedure at this point. Rhododendrons rarely sprout from old wood. By leaving a small cone with a leaf, a shoot or a sleeping eye when you cut, you can stimulate growth. The mentioned parts of the plant maintain the supply of nutrients, so that the shrub continues to grow at this point. Always cut on the leafy shoot "on cones" with a lateral, outward-facing leaf. On the bare branch, place the scissors 5 centimeters behind a fork to the younger side shoot. Where both are lackinglook 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 begin.

Rejuvenation cuts reverse aging - it succeeds in stages

If the ravages of time gnaw at a rhododendron, you are not powerless to face the gradual baldness. Spread over several years you can regenerate the old, aging shrub. Please do not be tempted to put the barren, barren ornamental wood on the cane in one go. In this case total failure is preprogrammed. 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 perform rejuvenation cuts between March 1st and October 30th
  • A third of the bald shoots derive from a young side shoot
  • Leave 5 centimeters of cones at the intersection behind the fork
  • Heavily aged scaffold shoots divert to the lowest side shoot near the ground

The figure below illustrates the first stage on the way to rejuvenation. Then fertilize the cut rhododendron generously with leaf compost and horn shavings (€ 6.39 at Amazon *) or special rhododendron fertilizer with an NPK formulation of 14 + 7 + 14. There is a waiting period of one year until the procedure continues as a combination of build-up and taper cut. You can find out how to do this in the following section.

Rhododendron taper cut


Proper cutting tools are crucial

The rhododendron cut becomes a horticultural success story if the right tool is used. As basic equipment for uninterrupted work, adequate scissors or saws should be available for every type of cut and drive strength. The one-handed secateurs, optionally with bypass or anvil mechanism, are suitable for shoots up to 2 centimeters thick. You can master branches with a diameter of 2 to 4 centimeters with two-hand pruning shears or a folding saw. (€ 17.70 at Amazon *) For a clearing cut on a majestic shrub with branches 4 centimeters in diameter and more, a high-quality sword or hacksaw should not be missing.

The body section completes the rejuvenation - this is how it works

Under ideal conditions, the first cones sprout after regeneration in summer. Remnants of cones dry up as they grow and can be easily removed. In the following spring, cut back the next third of overaged branches, again using the combined drain and tenon cut. The illustration below shows the correct procedure.

Take this opportunity to take a close look at all young ground shoots. Select the strongest specimens and cut off weak competition shoots at ground level.

If no cone has emerged, postpone the second stage of regeneration for another year. A lack of growth of young shoots signals that your rhododendron is still suffering from the rigors of the first stage. By doing without further pruning, you give the shrub the opportunity to gather its strength.

Cut rhododendron


Wound closure on rhododendrons is no longer up to date - with one exception

Thinning out old, thick branches or a comprehensive rejuvenation cut leaves large cuts on the rhododendron. Modern home gardeners leave the healing process to the shrub and no longer seal the wounds with tree wax. (€ 5.99 at Amazon *) The latest scientific research has shown that under the bark of every tree and shrub there is divisible tissue - the cambium. After wounds, cambium forms wound wood in order to cover the damaged area. This natural form of regeneration trumps horticultural measures by far. As a result, tree wax and other wound closure agents are being discarded in the home garden. The only exception is a thin layer of tree wax along the wound edges when frost could damage the valuable cambium.

frequently asked Questions

What is the difference between rhododendron and azalea?

The genus rhododendron includes more than 1000 species, including azaleas. For this reason, the popular Japanese azalea is known by botanists as Rhododendron japonicum. Regardless of the close botanical relationship, you can distinguish between the two flowering shrubs based on optical characteristics. A rhododendron thrives as an evergreen, mostly spreading 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 varieties contain a cocktail of various toxins. Not only the leaves are health-threatening, but also roots, buds, flowers and fruits. Excessive consumption causes severe symptoms of poisoning in humans and animals, ranging from nausea and vomiting to dyspnoea 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. Protect yourself with gloves when cutting. Do not dispose of clippings on the compost or in a pasture, but in the organic waste bin.

Can I use clippings to propagate cuttings?

Propagating rhododendrons with cuttings is a challenge even among plant experts. Tree nurseries usually multiply the ornamental wood by grafting. Instead of struggling with these complicated methods, we recommend the kneeling method. Semi-woody shoots near the ground are perfect. First remove all side shoots and lightly score the fabric on the underside. You dig the shoot with the wounded site in the ground. Fix the end of the shoot to a wooden stick. The mother plant and offshoot remain connected to one another until the offspring has developed its own root system.

Rhododendron buds die off - what to do?

They describe the typical symptom of a fungal infection caused by the rhododendron leafhopper. When they lay their eggs, the insects cause tiny wounds on the bud that use fungal pathogens as a gateway. Remove dead flower buds promptly and dispose of them in the household waste. So that it doesn't get that far, you can use yellow panels to prevent the female cicadas from laying eggs in August and September.

The 3 most common mistakes

No master of the rhododendron cut has fallen from the sky yet. 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 cutting errors with tips for prevention.

Cutting errorsDamageprevention
withered flowers not trimmeddiminishing abundance of flowersBreak out withered flowers promptly
aged rhododendron put on the stickTotal failureRejuvenate the old shrub in stages
not cut back on tenonsno new shoots at the interfaceAlways cut branches with a small cone and a lateral leaf or shoot


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