How To Prune Rhododendrons?

Rhododendrons are a fast growing plant, and one that can quickly take over if left unchecked. So let’s have a look into how to prune rhododendrons for best effect!

How Fast Do Rhododendrons Grow?

how fast do rhododendrons grow

Rhododendrons are generally a big plant. You can keep them in check with pruning, but bear in mind that these bushes can grow incredibly big!

You can, of course, buy smaller varieties if you have a smaller garden, or want to keep them in pots.

Of course, each plant is different, and each will grow differently due to its conditions, so you must factor in your growing conditions when working out growing times.

With the perfect conditions, a very fast growing rhododendron can reach 60cm of growth in a year. The slower growing varieties can manage 1cm per year.

In less than ideal growing conditions you will find that your rhododendron grows much slower.

If you are going for truly big growth, you will need dappled sunlight, acidic soil and a warm climate.

If you do not have these conditions, your rhododendron will still grow, but it may not be as large or as vigorous.

If your rhododendron is a bit sluggish, consider adding some fertilizer in early spring, or even moving its position to a more favorable one.

How Big Do Rhododendrons Get?

There are a few different types of rhododendron, as there are most plants, and the different types will grow at different paces.

Rhododendrons are generally strong, vigorous growers, and one that can easily take over a garden!

The biggest types will grow to around 6 feet at their maximum, while smaller types can reach about 3 feet.

This being said, rhododendrons will not self limit or die back, and with the right conditions they will simply grow and spread for the rest of time!

If you are looking for a lovely, attractive bush to cover a large area, go for a few of the larger types, planted far enough apart that they have room to grow.

Those in smaller gardens, or keeping their rhododendrons in pots, it is wise to stick to a few clumps of the smaller types.

When To Prune Rhododendrons?

when to prune rhododendrons

This is not an overly sensitive plant, but you would do well to make sure that you do not prune it willy nilly throughout the year, and stick to one specific time.

Rhododendrons are best pruned as soon as the bush has finished flowering for the year. This will ensure the plant has enough stored energy to make new flowers the following year.

Once the flowers have died back, you may find your fingers itching to deadhead those old, spent blooms.

Do it! Dead heading will encourage future flower growth, as well as making your rhododendron look more attractive.

As you snip off the dead flowers, you should also check for signs of dead or diseased branches and leaves, and give these a good trim back too.

It is best to stick to heavy pruning only once a year, however much you may want to trim the bush further, to ensure it has enough energy for the following year.

If your rhododendron needs a really good haircut, wait until late winter, while the plant is dormant and before it has started putting its energy into flowers for the year.

Any time between the first and last frosts is a good time to really get stuck into pruning your rhododendron.

This informative article will tell you all you need to know about dead heading your rhododendron.

How Do You Prune A Rhododendron Bush?

Despite their reputation as a plant that will take over your entire garden, rhododendron actually need surprisingly little pruning.

You can deadhead your rhododendron, and be safe in the knowledge that it will produce more flowers the following year.

At the same time as dead heading, you should check your bush over for signs of disease or dead branches, and cut these back too.

If your rhododendron is taking over your space, and needs a bit more of a brutal cutting back, you can do this too:

  1. Take a good sharp saw, and ensure that you are wearing adequate protection (gloves, goggles and thick trousers).
  2. Cut back the largest branches, ensuring that plenty of light reaches the younger stems below.
  3. You can choose to spread your cutting back over a few years, as not all rhododendrons respond very well to this harsh treatment.
  4. If you are attempting this harsh pruning, it is best to wait for a frost free day in late February or March, in order that your plant will not become too stressed.
  5. After any vigorous pruning, it is advised to water and mulch your plant well, to give it a proper boost.

This video will show you everything you need to know about pruning your rhododendron:

How To Cut Back Overgrown Rhododendrons?

If your rhododendron has gone beyond the point of normal pruning and dead heading to keep it under control, it may be time to bring out the big guns!

  • With any pruning it is important to make sure you are protected – wear goggles, thick gloves and strong sturdy trousers.
  • Work out how much of your rhododendron you want to remove, and plan which branches you are going to cut first.
  • Using either a saw or some really strong loppers, take back the largest branches close to the main trunk.
  • You may need to use a wood saw or even a chainsaw for those branches that have really gone wild.
  • Once you have removed the largest offending branches, you should tidy up the rest of the bush to make it the shape and size you want.
  • This sort of pruning is best done at the very end of winter or very early spring, to allow the plant time to recover.

Rhododendron is a fantastic plant, producing loads of wonderful foliage, plus filling your garden with pretty flowers. Hopefully you now have a better idea of how to care for them!

2 thoughts on “How To Prune Rhododendrons?”

    • As long as your plant is healthy, there is no reason why it cannot make great compost. This being said, some parts of a Rhododendron can get pretty big – if you have had a large prune and cut down big branches, a bonfire might be a better bet.


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