Spiraea, sometimes spelled spirea in common names, is a genus of about 80 to 100 species of shrubs in the family Rosaceae. They are native to the temperate Northern Hemisphere, with the greatest diversity in eastern Asia. They are deciduous shrubs that can be divided into two categories: spring blooming and summer blooming. In this article we will see all about how and when to prune a spirea shrub, you will see that although it is not something complicated there are several aspects to consider for a good pruning.

If you read to the end you will learn the best techniques for proper pruning, the right time to trim and the tools to do it. The article has no waste, I assure you. 😉

Note: Please note that the advice given here is general, this blog is consulted from many countries in the world, with totally different characteristics, what not all tips will be adapted in the same way in all cases. Once you finish reading the article it will be necessary to analyze all the information and apply what you have learned in the best way. If you have any questions, remember that you can contact us to make your inquiries.

1. How to care spirea bush

Although the pruning of spirea is the central axis of this article, it does not stop being one of several of the caution that this bush needs to be healthy, strong and beautiful. In this section we will see the key care of spirea.

  • Sun: these shrubs prefer locations in full sun or with slight shade. If they are placed in places of exessive shadow, development will be delayed.
  • Irrigation: needs a regular watering during the summer, a mulch will help to retain moisture better.
  • Fertilization: it is advisable to fertilize once a year, with two inches of compost at the base of the shrub. The time may be late winter or early spring. A key aspect is to never fertilize during the autumn, this can generate a late sprouting that will be lost with the first hellas, damaging the plant.
How and when to prune spirea bush
Spirea bush
  • Pests: although the spirea is a shrub that is not usually attacked by large pests, there is the possibility of attacks by mites and aphids. If you are being severely attacked you will have symptoms such as discoloration and falling leaves. Observe with some regularity the existence of these insects, and if necessary apply insecticide (consult an expert before acquiring said insecticide).
  • Pruning: as I said well this is one of the key care, then we will develop everything on this point.

As you may have noticed taking care of a spirea is not a very complicated task, this along with its beauty are the most important aspects for which gardeners love this bush.

2. Tools needed to prune or trim an spirea bush

There are several tools that you will need to perform your pruning or trimming of a spirea. Each of them is appropriate for different cases depending on age, time of year, type of pruning, etc.

  • Hand Pruning Shears: Stems up to half inch in diameter can be pruned with hand shears.
  • Lopping Shears: It is suitable to use on stems between half inch and 2 inches in diameter.
  • Pole Pruner: Pole pruners have a hooked blade above and a cutting blade beneath. The blades are on a 5- to 6-foot long pole and are operated by pulling on a long piece of cord.
  • Hedge Shears: Manual and power shears are available for trimming hedges. Manual shears have long, flat blades with relatively short handles and are good for small jobs. Electric shears are a good choice for larger hedges.
  • Saws: A number of pruning saws are available. These saws come with either curved or straight blades and of variable lengths and points. Curved blades that cut on the draw stroke are easy to use.

Keep in mind that you must disinfect all the tools before trimming your spirea. This will help prevent disease transmission, you will have to do it before you start pruning and every time you change plants.

2.1 Needed care of pruning tools

If you want to extend the useful life of your pruning tools there are some basic care.

  • Use the right tool for a job and avoid twisting or straining it.
  • Clean and oil tools regularly by wiping an oily cloth on blades and other surfaces.
  • Keep cutting edges sharp by regularly using an oilstone.
  • Wooden handles should be varnished or regularly treated with linseed oil to keep them from cracking or splintering.

Carry out the previous care on a regular basis and you will be saving good money on tools. 🙂

3. Why you should prune your spirea bush

There are many reasons why, throughout the life of your spirea, you will need to prune or cut. Among the most common reasons we can mention the following:

  • When we want to vary the shape of the bush or make the plant stand out more. For example, in certain points of the garden you can interteresar the broader or smaller development of certain shrubs.
  • When we want to improve the quantity and quality of flowers, in those species that are decorative for them.
  • When you have to rejuvenate weak or sick shrubs. In this case we will have to act with energy suppressing the diseased parts and lowering the shrub to its main branches to achieve a new and vigorous vegetation. Sometimes it will be necessary to eliminate some of the main branches or, even, to decapitate the bush.

You may also be interested in knowing about pruning:

4. When to prune a spirea

If you have a spirea in your garden there is no doubt that you like it to flourish in the best way possible. Since if you prune a spirea are directly influencing your flowering, you must choose the right time to make the cuts without damaging it.

Pruninig spirea
Spirea bush

Selecting the time to prune according to the flowering we will find several options depending on the variety of the spirea. As we said there are hundreds of varieties, but all can be grouped in some of the following three cases:

  • Spireas that bloom in spring: in this group are for example the Thunberg spirea and Vanhoutte spirea. The right time to prune the species that bloom in spring is after flowering, ie late spring.
  • Those spireas that bloom during the summer: in this second case there is the false spirea, and it must be pruned before the growth of spring begins.

As you should have noticed, selecting when to prune a spire comes completely hand in hand with the variety of it. Know when it blooms and you will know when to trim.

5. How to prune spirea bush

Performing spirea pruning is really not a difficult task, and there are several recommendations that it is good to know before beginning the task.

5.1 General tips for a good spiraea pruning

Before seeing step by step how to make the cut of this floral plant is important to know the following recommendations:

  • You must know how to recognize the structure of the spirea, knowing how to differentiate pacifiers from floral branches.
  • Understands the benefits and harms of pruning, each cut is a wound that can influence positively or negatively on the development of spirea.
  • Understands that pruning after flowering is a practice that is carried out to give the bush as much time as possible for new buds before the next flowering.
  • As I said, cutting the spire generates wounds, but that should not scare you. This bush adapts very well to pruning, you must perform a very bad and debastadora task to damage it in a remarkable way.
  • A recently transplanted spire does not need to be almost pruned, you can make some slight cuts to give some shape to the bush.
  • Once the pruning is finished the task does not end there, you should give it some extra care so that the bush responds better. It will be enough to water it, fertilize and change the mulch.
  • If you want to reproduce your spirea when pruning is a good time. If the plant is already several years old, it will not be difficult for you to divide some stems with roots from its base, use them to create new plants.

5.2 Spirea pruning step by step

We have already seen the whole theory, from which tools you use, how to select the right time for pruning and some general advice. We are ready to start the task. 🙂

Follow the steps below and in a few minutes you will have finished:

Step 1: Start by cleaning the base, leaving everything that limits a good vision of the plant. This will allow you to correctly observe the development you have had since the last pruning.

Step 2: Having already a good overview of the whole shrub you should recognize all the dry and diseased branches, cut them to each one from the base.

Pruning spirea
Pruning spirea

Step 3: Another element that must be eliminated from the base are those branches that have been pruned previously, and have developed new very weak boraciones.

Step 4: find the plant suckers (buds that emerge from the roots of the plant), not cuts at all, you may need them for the development of the plant. Those that cuts should be from the base.

Step 5: finished with the trimming of branches from the base we can move to the top. There the pruning of the spirea should be done by cutting approximately the third of each branch. Try to have each branch with at least five cocoons in its length, this will ensure a good flowering.

Step 6: If finished with the task of pruning, it still seems that the shrub is too dense, you can perform a selective thinning to decrease the density.

6. How to prune an old spirea – Rejuvenation

If your spirea has been around for many years now, and you see that a pruning like the one we have just detailed does not have the expected effect, that is, it does not develop good buds and its flowering is poor. You should consider carrying out a more severe pruning, which is known as rejuvenation pruning.

This pruning can be carried out in two different ways, one with a long-term renewal and another more immediate.

6.1 Case 1: Rejuvenation in three years

As the title indicates, we will schedule the renewal with the pruning of the spirea for three years.

In the first pruning, remove the large, old branches from the ground level and leave the branches young and vigorous. At the beginning of the second and third growing seasons, you should also cut back the water sprouts or suckers that developed. Cut this new growth to different lengths and encourage them to develop into strong branches for the shrubs by thinning them.

6.2 Case 2: Rejuvenation in a season

I have already said several times, the spirea responds very well to pruning, which is why it can withstand a very severe pruning to reactivate its development.

Rejuvenation pruning involves cutting back the entire top of the plant to the ground line. Many new shoots will grow from the base, and they will require thinning.

Spirea rejuvenation pruning
Spirea rejuvenation pruning

In the following season many new shoots will have developed, select three quarters of the strongest and eliminate the others.

7. Spirea trimming – Video

To finish with the article, and as usual in this blog, I leave a good video (of the Earthform Landscaping, Garden Centre, Pool & Spa channel) where several of the concepts seen so far are reviewed.

Well I hope you have understood everything about how and when to prune a spirea bush, and that when you take your scissors you have no doubt. 😉

You may also be interested in knowing about pruning:

Source information:

Pruning Ornamental Trees and Shrubs – Rosie Lerner & Kyle Daniel, Department of Horticulture and Landscape Architecture Lindsey Purcell, Department of Forestry and Natural Resources