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Camellia pruning revisited.

Camellia pruning revisited.

I wrote an article on pruning camellias two years ago in this post. I’m not sure that in writing a new article I’m saying anything much that’s new, but I have added more detail about some aspects and it now feels more complete. There is also new functionality on the WordPress blog which I wanted to take advantage of for before and after comparisons.

The advice in most of my books seems to be a variation on regular pruning being unnecessary for Camellias with a rider that if they get too big they can be cut back severely. I wouldn’t say that either of these is untrue but it does lack detail and for anyone growing Camellias in a confined space some regular pruning will almost certainly be needed. I have been growing camellias in Cornwall for many years and for various reasons have found myself carrying out a lot more pruning of them than one might be led to expect.

In setting out what I have done and what has resulted from it, it is important to realise that Camellias will grow differently in different conditions and that it is a very large group of plants not all of which will have the same growth pattern and which will not all respond in the same way to a particular pruning method.

How Camellias grow.
A “typical” deciduous shrub, Spiraea for example, has a suckering habit. It has multiple stems from ground level and each year, if in good health, will produce several more. The new shoots grow quickly to the height of the shrub, with little, if any branching. In their second year they produce laterals on which the flowers are carried. The following year sub-laterals are produced and carry the flowers. Under the weight of increasing twigginess and flowering, the branches arch over and the new growth, which is fairly upright, comes up through the middle of the bush. Pruning consists of taking a proportion of the oldest, twiggiest, least flowery shoots each year. The plant is constantly renewing itself and even without pruning, the oldest branches will die off and be replaced by new ones.

Camellias do not renew themselves in this way. Like “typical” trees, they usually have a single stem at ground level and produce extension growth over their entire surface each year. This extension of the existing shoots may be as little as a couple of centimetres or as much as 60-80cms. Growth typically happens in two phases. In spring the buds break and produce a shoot between 5 and 15cm in length. Each dormant shoot may grow just from the terminal bud or from the terminal plus one to four or five lateral buds. This phase of growth is complete by May or June and is often all that is produced in the whole growing season. If that is the case, flower buds will usually form at the apices of both the terminal and lateral shoots. Alternatively, the terminal bud will break again in July or August and make further growth, usually a good deal longer than the earlier growth. This may happen across the bush, on a limited number of shoots at the top of the bush, or not at all. It makes the difference between the plant putting on 5-15cm in the season, or 65-85cm. Because this growth is produced quite late in the year, it rarely produces flower buds.

In the images below the early 2019 growth flush is marked in red, the late flush in blue. Some of the less vigorous laterals have flower buds, some not. The apical buds have made much longer second flush growths, none of which have flower buds. Only the early flush growth from 2018 and 2017 remains as the second flush growth was all pruned off in the autumn of the year it was produced.

Formative pruning.
By this I refer to the pruning required to get the plant off to a shapely start in life. Nurseries aim for a bushy, well budded plant as this is what they believe their customers want. To this end the first flush growth is pinched to encourage several second flush growths rather than one. This makes for a stocky, sturdy plant with several low branches. Planted out as a free standing plant, this will make it easy to maintain a foliage canopy right to the ground. My own preference is to allow the bush to develop more naturally so that it has a single stem for the lowest foot or so, branching naturally, i.e. not too densely, above this. In this case the first flush growth is not pinched but allowed to break naturally.  In both cases the second flush growth will be shortened or removed completely as it will be unnaturally long if, as is usual, the young plant is growing under cover.

Once planted out, the rate of growth will be slower, but depending on the variety and how you want the plant to develop, removal of some or all of the second flush growth will likely carry on for a year or two at least.

Regular pruning.

If the space available is small, it is folly to plant a variety that will outgrow it in just a few years. If the bush has to be pruned to keep it at a fraction of its natural size, it will be at the expense of flowers and there will eventually be little point in having it at all. There are some smaller growing varieties, a few with a narrow upright habit and a few that keep quite low and grow sideways. The vast majority of readily available varieties however, will want to grow to a height of at least 3-5m with a width only a little less. If space permits, the plant can be left to develop on its own without any pruning and this is likely to give you the best flower displays.

If control over growth rate is required, the first and easiest option is to remove the second flush growth entirely. By August or September it is easy to distinguish flower buds from vegetative buds, the flower buds being much fatter. The purely vegetative growth can be removed from autumn onwards, so long as it is left late enough for their to be no risk of encouraging renewed growth. I have removed this type of growth from mid September on without any problems. There is the additional benefit that the flower buds are not now hidden beneath new growth so that in spring, when they open, they will be seen to best effect.

In the images below I have shown two possible pruning options but while you probably would chose to keep all the flower buds, how much or how little you prune off above them is entirely optional. Removing all the non-flowering shoots leaves the flower buds on top of the bush where they will be seen to best effect. Whether, as in summer pruning of fruit trees, removal of all the vegetative growth reduces the overall vigour of the plant, promoting flowering, or alternatively, is quite rigorous pruning that may encourage strong growth the following season, I don’t know. I believe other factors have a much greater influence on the plant’s response.

By this means, growth is restricted to the length of the first flush growth, usually 5-15cm a year, but it is not stopped altogether and the bush will still get larger. In the following sequence of shots, taken after autumn pruning to remove the second flush growth, you can see that this vigorous growing bush of Camellia ‘Debbie’ has made about an extra 15cm height each year.

These two shots from 2nd September 2018 show how much more growth there would be each year without pruning.

It may be that even at this controlled rate of growth, the bush gets as big as you want it to be and you wish to keep it at around the same height indefinitely. To do so, an additional pruning operation is required. In spring, as the last flowers fade but before new growth starts (a window that not all varieties provide) more growth is removed.

The aim is to keep the bush looking as natural as possible; to remove as much growth as required but to not be able to see where it has been removed from. This is a job I do every two or three years, meaning I need to remove two or three years worth of growth to maintain the size of the bush. I track the shoots that form the extremities of the bush back into the bush, to a well furnished sideshoot, then cut the main shoot just above the sideshoot. Repeat this over the entire bush and the overall outline will shrink but still look reasonably natural. It doesn’t have to be done with great precision but you do need to know exactly what you are about to remove before you make the cut. I find it works best if I don’t overthink it, but I’m aware that’s easy for me to say.

You can easily end up removing quite a lot of growth from the bush and the more you remove, the greater is likely to be the impact on flower bud production later in the year. It may also encourage more second flush growth but that is simply removed later in the year.

Removing second flush growth inevitably leads to a denser bush, with more shoots produced on a bush that is not increasing much in size. Thinning out the growth can make for a more pleasing appearance, especially on a plant that has a clear trunk and something of a tree habit. The method is the same as for reducing the size but with the focus on the densest areas of the canopy rather than the tallest shoots. Don’t get carried away, removing a third of the canopy is as much as should be done at one time. It is also the case that a very dense canopy of foliage will shade out leafy growth inside the bush, leaving nothing green to cut back to if you want to reduce the size of the bush. Reducing the density of the canopy lets more light through to the ground below, perhaps opening up possibilities for growing shade lovers beneath the bush.

In the sequence below I reduce my Camellia ‘Bob Hope’ by 30-40cm. I start by visualizing where I want it’s outline to be and what currently is beyond that. I cut out longer shoots, hiding the cuts within the new outline of the bush. You can see the length of the shoots and the beginnings of new growth in the pile of prunings. Two years on, it has put back on what was removed and is covered in flower buds. I will probably prune it again this year or may leave it for one more year.

Not so regular pruning.
If you plant camellias in significant numbers and allow less than four metres or so between them, then leave them to grow without intervention, you will eventually end up with a spooky dwarf woodland, very dark, with smooth sinuous trunks supporting an unbroken canopy of evergreen foliage. Dead leaves and flowers will often accumulate in the foliage canopy, making it denser still, and it may be that a fine flower display is produced above it each year but you won’t know, because you won’t be able to see any of it. If only this were an exaggeration, or even a rarity; sadly it is not.

In an ideal world, such a situation would not arise but we don’t live in an ideal world. Once this point is reached, or preferably a lot sooner, rather more drastic pruning is required. Fortunately, Camellias usually respond remarkably well to harsh pruning, but it would be untrue to say there are no risks involved.

Before carrying out severe pruning on a camellia it is as well to have a pretty clear idea of what the response will be and what you want to end up with. If the bush is twice as high as you want it and you remove half its height, the very first growth it makes takes it back above the height you want. In most circumstances it is better to err on the side of cutting too much off rather than too little.

When cut through their main branches, Camellias respond by long dormant buds growing out to replace what has been removed. Almost always, the vast majority of regrowth will be within 30cm of where you made the cut. Growth is often vigorous, predominantly vertical and you can expect 6 shoots or more to grow from every cut branch. In good growing conditions you will get two flushes of growth a year and 60-90cm increase in height. If conditions permit, that vigorous growth can be repeated for several years, taking the bush back to its original height in around five years. The exact response seems to depend heavily on the growing conditions the plant gets in the years following pruning. In drier, sunnier locations, there may not be enough moisture available by midsummer for the plant to make a second flush of growth. The short early flush growth gets a chance to produce flower buds instead and the desired end of a smaller, but free flowering bush is achieved. If moisture is available the bush may soon be back to the size it was before pruning, but with growth much denser than before and with minimal flower production.

You may choose to prune the bushes down to 50-100cm so that the regrowth is at viewing height. If deer are a problem, they may feast on the regrowth, so pruning should be higher, aiming to produce regrowth beyond their reach. There is also a slightly increased risk of killing the bush with more severe pruning. The biggest drawback with this mode of pruning is that the regrowth is often so strong that in around five years the plant is back to the size it was before and often only just beginning to flower freely again.

This type of severe pruning is usually carried out immediately after flowering and before new growth commences. From the point of view of the plant’s response, it would best be done between mid February and mid March irrespective of flowering but the difference it makes is probably not very significant. By June or July new shoots will be pushing through the bark, concentrated in the 15-30cms behind the cut end. There are likely to be many shoots, all around the branch and by seasons end there may be up to 30cm of new growth.

Essentially you now have the choice of letting the plant grow back unchecked or adopting one of the strategies described earlier to keep the plant’s size in check. If you decide to try to keep the plant under control, you need to manage the very strong growth that is likely to occur following hard pruning. The response can vary a great deal, you may get dense masses of short, early season shoots and no late season extension growth or you may get metre long shoots with hardly a pause between first and second flush. What you do next depends on how the plant has behaved. Dense clusters of shoots should be thinned out, removing half to two thirds completely, cutting as neatly as the bunched shoots allow. The following year there will probably be the usual pattern of two flushes of growth. Much or all of the second flush growth can be removed in the following winter and further thinning can be carried out at any time. Thinning should be targeted at the densest clumps of shoots. It may be easier to remove whole branches with all their new growth in some instances, especially if the branch system is congested following earlier hard pruning treatment.

Some varieties will produce new shoots all along the branches but most will have them heavily concentrated near the cut branch ends. New growth around the sides of the bush is likely to be sparse compared to that at the top. Shoots arising from well down the main branches can be left to furnish the lower parts of the bush or removed to create a clean limbed, tree-like effect.

Very occasionally the bush will respond by producing no new growth and dying. Sometimes parts will make regrowth and other parts will die. Sometimes there will be strong re-growth only for it to wither during the winter and the whole branch or bush to die. Even when this happens it is as well to cut off the dead wood but not rush to dig out the roots as a proportion of apparently dead plants will rise, phoenix like, by producing new shoots from below ground. In my experience regrowth followed by winter dieback or death is only likely in cold, wet situations such as north facing slopes under trees and even then affects only a small minority of bushes.

In a large collection, it may be available time that dictates how plants are managed. To carefully thin and reduce a plant every two or three years may take 30-45 minutes per plant, requiring skilled labour to do it. Hard pruning can be done in ten minutes per bush using unskilled operatives and not need repeating for a decade. In the latter situation it is unlikely that there will be any follow up to the “hatrack” pruning, the bushes being left to grow unchecked until it becomes necessary to repeat the process.

Another factor is the scale of the planting and the size of the plants within it. In my small garden 2m is as tall as I want to allow most of my camellias to grow. That does mean that regular pruning is required but it also means that the entire bush is within reach of my secateurs from the ground. In a larger scale planting, 2m is the point at which the plants start to look in scale with their surroundings and 3-4m tall bushes may be the norm. Even on flat ground working from step ladders on a bush 3m wide is challenging. On a slope it is almost impossible and quite hazardous. I have a telescopic pruner which makes it possible to prune 3m bushes provided they have something of a taper in to the top, rather than being very rounded. Second flush growth can be fairly quickly pruned off, any time between mid September and spring. Accuracy of cutting isn’t critical but working from the ground can lead to a stiff neck and bright sun can be very unhelpful.

Managing a collection becomes a matter of deciding how each of the plants is going to be managed, trying to avoid pruning where possible, keeping it simple and ground based and spread it over as wide a time period as is compatible with the needs of the plants and other tasks that must be carried out. Received wisdom is that Camellia reticulata responds much less well to hard pruning than do the other more widely grown groups, so these should be planted where they can be left to grow naturally. Certainly bushes in poor health are likely to respond poorly, it is not a reliable method of rejuvenation and likely to fail if the reasons for the plant being in poor health are not identified and addressed.

The following images will hopefully give you a clearer idea of what the likely response to severe pruning will be. There is no certainty about it but it may help you to get where you want to be in a shorter time.

5/6/2018 ‘Twiss Cornwall’, or ‘Saturnia as I’ve now realised it should be, two years after severe pruning. It was cut high to be out of reach of deer. I’just thinned it at this stage. I need to use my telescopic pruner to remove late season extension growth later in the year. Note that in addition to thinning the new shoots I’ve also removed a little more of the main framework.

Finally, by way of saying keep your eye on the prize, five camellias in my own small garden, where keeping things within bounds is essential, photographed five minutes ago. All have been pruned to a greater or lesser degree, I don’t want them all looking the same and I certainly don’t want them to look like topiary. I do want them to flower well and I do want them to look at home in a fairly informal garden.