Growing Photinia ‘Red Robin’ – Planting, pruning and common problems
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The Photinia Red Robin is a recognisable variety from a distance thanks to its vibrant bright red foliage in spring and clusters of beautiful small blooms around May-June. Photina is a fairly quick growing evergreen shrub that is perfect for any garden as they are easy to grow and do not require much maintenance, and respond well to pruning that will help to keep them under control size-wise. They do grow around 1ft a year and the eventual height can be fairly large at around 4 meters (13ft). However, with a little pruning every year or two you can easily keep them at around 4ft by 4ft.
To grow these hardy plants you need to have some knowledge so as to avoid the common pitfalls that may damage the plant. This is mainly pruning the shrub too late in the season, which will leave the foliage suspectable to frost and this can damage new growth.
In this article, I talk about how to grow Photinia Red Robin and additional care tips for optimal growth. First things first, let us look at planting a Photinia to give it the best start.
Choosing the right position
The Photinia Red Robin is a hardy plant, hence it can survive in tough environments and will grow in most parts of the UK. However, perfect conditions for growth include well-drained soils with good ventilation and they prefer plenty of sun but will grow okay in a partially shaded area too.
These evergreen plants can even grow well in clay as long as you add some peat and compost to promote proper nutrition and correct drainage of the soil. It is the water-logged soil they dislike, as do most plants.
Even though they grow well in partial or full sun, taking care to provide shelter against strong winds is highly recommended. If you have ever seen Photinia leaves with black spots on them, it is often mistaken for a disease. However, it is usually caused by cold winds, nothing that could kill the plant. As long as they get some sun and adequate nutrition, these plants can grow into sizeable shrubs and even work well when planted as a hedge.
Caring for Photinia Red Robin
Although Photinia plants may take a while to establish themselves, once they do, there is no stopping them. When first planted they do need frequent watering but once established it is just a case of pruning to retain shape and remove any diseased or dead sections. Only during longer periods of dry weather would they need watering.
Pruning Photinia properly
Please note that Photinia Red Robin can do without pruning but if you want to retain a certain size or aesthetic, pruning is recommended and they respond very well even to hard pruning. Without pruning, the bush will grow wide and to about four meters (or higher) in height.
When to prune Photinia
The perfect time to prune Photinia is at the beginning of the growing season, as this will promote better growth. You could also prune after flowering which would be around May to July. Pruning after July is not recommended as it will put the plant at risk of frost damage.
You do not have to prune young Photinia Red Robins until they mature unless they have long scanty branches. In this case, pruning tall but skinny plants when they are young will help promote bushier plants.
Remember that Photinia are hardy plants and therefore, they can take severe cutbacks. Just make sure you prune in time to give the plant enough time to recover before the winter sets in.
Usually, if you buy plants from a nursery, they haven’t fully matured so they will need some attention. You will need to replant it in your garden or in a sizeable pot that can house the plant permanently. Whether you plant them in the garden or a pot, ensure the hole is at least twice the size of the root ball. If you choose to grow one in a pot this means you will need a fairly large pot.
Plant in a position with plenty of sunshine and offer some shade to facilitate healthy growth. If you live in an exposed area with cold winds, try to choose a more sheltered position. Mix in a little compost to feed the plant and water adequately to avoid wilting.
Planting a Photinia hedge
If you are using these plants for hedging, spacing is important to ensure effective ventilation; therefore, place them at least 60cm apart from the wall and space them 60cm apart as well.
Read next: Growing delphiniums in pots
How to propagate Photinia
The Photinia Red Robin is a hybrid between Photinia and Fraseri; therefore, it may be challenging for the plant to produce seeds. However, you can purchase these seeds online and plant them successfully. The challenge of propagating Photinia Red Robin seeds is that they require stratification, and this takes time. Stratification permits the seeds to break the dormancy phase into germinating by imitating natural environmental conditions. In general, it is much easier and more successful to propagate Photinia (and most shrubs for that matter) by taking cuttings.
How to take cuttings from a Photinia
Cuttings are one of the easiest ways of propagating Photinia and fortunately, it doesn’t take a long time. The most suitable time to take cuttings is around mid-summer when you can take softwood cuttings.
Take cuttings that are around 6 to 10 inches long and have 3 nodes (this is where the leaves sprout from) and simply remove the lower leaves on the cuttings. If you are taking pots of cuttings, which I recommend, then you can place them in a clear zip bag with a little water in and they will be good for an hour. This will give you plenty of time to work through planting your cuttings and will prevent them from drying out in the wait to be placed in a pot.
Carefully fill small pots with cutting compost or mix 50% perlite with 50% multipurpose compost.
Next, dip the cuttings into some rooting powder before immersing into the soil to encourage healthy root development. I like to plant several cuttings into each pot. The most common reason for cuttings rotting off is too much moisture and by using 3 or 4 cuttings in each pot I find they are much more successful in taking. You can use any small pots but I like to use 9cm or 1-litre pots.
When placing the cuttings in the container, make sure they don’t touch each other. Every cutting needs adequate space to establish its own rooting system. Place the cuttings in an area where they can get some sunlight and keep them well watered. After a couple of months, expect to see new growth in the cuttings and the development of well-rooted systems. Once they are well rooted, you can either pot them on into individual pots to grow on further or plant straight into the ground.
Plants are susceptible to attacks from pests and diseases. It is up to you to note any issues with the plant and act quickly to prevent irreparable damage. While it is normal for Photinia Red Robin to drop leaves occasionally, excessive defoliation or discoloured leaves are a point of concern.
Below are some of the pests and diseases that may affect a Photinia Red Robin.
Black spots caused by the cold weather
The most common problem with Photinia is black spots on the leaves. These are often mistaken for a disease but it is thought to be caused by the cold weather. This does not harm the plant but to help prevent this they are best planted in a more sheltered position away from cold winds.
Other diseases that affect photinia include:
Honey fungus, as the name suggests, is a fungal infection that spreads through the roots. The fungus destroys the roots of the tree and above ground can develop into mushrooms in the autumn. It may hide between the bark and wood, making it hard to spot unless you strip the bark.
If you are sure that it is a honey fungus, uproot the plant and burn it, as there are no viable chemical controls. Then utilise pond lining or a heavy-duty plastic sheet on the soil to prevent any rhizomes left in the soil from developing and spreading.
This fungal disease affects plants worldwide and the Photinia is no exception. The infection is identified by the presence of dark spots on the leaves that continue to increase in size and develop red outlines. If unmitigated, the disease causes defoliation which weakens the plant.
Remove all the diseased sections and prune severely around May to give the plant enough time to recover. The use of fungicides will prove effective if you catch the infection early and continue to treat it through the autumn and winter.
Placing fresh mulch around the trees will act as a barrier in preventing the spores from spreading.
Powdery mildew is another fungal infection that affects Photinia. It is fairly common and easy to identify. This infection looks like a white powdery substance that coats the leaves and buds. The leaves will eventually discolour and fall off which is bad news for the plant because leaves are necessary for food production. Apart from removing the diseased parts, prune the plants occasionally to improve circulation and use mulch as a spore-spreading barrier.
There are plenty of copper or sulphur fungicides available for powdery mildew treatment on the market.
Originating from the bacteria Erwinia amylovora, although not that common, this disease manifest as cankers that secrete a brown liquid. This infection typically appears around the late spring, making the plant look like it has been scorched by fire. Although there are no fully functional chemical interventions for fire blight, removing and burning the infected parts will help. Use disinfected cutting tools in between cuts to stop any re-infection. In severe cases, it is usually recommended to remove and destroy the plant.
Root rot emerges from fungus such as Phytophthora sp that invades and infects the roots. Overly wet conditions in the roots, thanks to poor drainage, can catalyse the situation and that is why you are advised to plant the Photinia in well-drained soils.
Symptoms of root rot include discoloured roots, wilting leaves and limb dieback amongst others. There are chemical control measures for treating root rot but the infection needs to be identified early to prevent it from spreading.
Pests that attack Photinia Red Robin
Mites do not do a lot of damage unless in large populations. These insects suck the nutrients from the leaves causing them to discolour. These tiny pests are hard to see, but they leave tiny webs behind that are easily identifiable. Dealing with mites is easy; just spray some neem or horticultural oils to remove them without introducing chemicals to the soil.
European fruit-tip moth
Also identified as the oriental fruit moth, Grapholita molesta attacks various plants. In its larva phase, it invades new shoots and causes the leaves to drop. Use the braconid wasp as a long-term control method. There are several products on the market that include spinosyn and esfenvalerate among other compounds that will help control the population.
Scale insects damage the plant by sucking off the sap. This causes discoloured leaves and eventually, the stems will die back and this affects the plant’s vigour. Scales also produce honeydew, which then attracts other insects like aphids and ants to the plant.
If left unchecked, scale infections could cause irreparable damage to the plants. The use of insecticides or employing natural predators like lacewings or ladybugs is highly recommended.
As you can see, growing Photinia Red Robins is fairly easy. Just ensure the plants are well watered, pruned occasionally and protected from common diseases and pests.