Pests & Diseases - Photinia Leaf Spot
Published: 16/04/2018
Many of you who are getting back into the garden after the Winter and recent wet weather may be wondering why their usually chirpy Photinia x frasieri 'Red Robin' is looking very sorry for itself all of a sudden.
The usually clean, glossy green older leaves that create the backdrop for the show of younger red ones are now blotched all over with purplish-red-brown spots!
You may be wondering "Is this a fungus? Is my Photinia dying of some disease? Has a garden pest taking up lodging and caused this?"
Thankfully no, so don't panic!
This is what is known as Photinia Leaf Spot.
What is Photinia Leaf Spot then?
It is a problem specific to the Photinia family that is caused when the plant is put under great stress.
Will it cause permanent damage? 
What has caused this to occur?
As mentioned, Photinia Leaf Spot occurs when the plant undergoes great stress. This can be from nutrient deficient soil, cold weather, drought, etc.
Photinia should be planted in a sunny, well-drained location. As non-native plants from a warmer climate than the UK, Photinia should be hardened off before being sold in nursuries and garden centres. If this is not done so correctly the plants can be shocked by the colder weather we receive in the Winter months.
Now as you remember, we have just trudged through a milder/wetter than usual early Winter and then experianced a colder late Winter than usual, which also brought with it a barrow full of snow!
Shocking! But even more so for Photinia! Thus we have the reason for the Photinia Leaf Spot.
So what can be done about it?
Once May comes around (as the weather can more reliable) it is useful to prune back the Photinia a few inches, remove the affected leaves and keep the ground beneath clear of leaves (this is in the case of Entomosporium which looks similar and occurs under similar circumstances. However, it is much rarer than Photinia Leaf Spot and is dealt with in the same way).
Aside from that just try to give it as comfortable a year as possible, i.e. not neglecting it if there is a drought in the hotter weather, not letting it get waterlogged if we experience a wet summer, etc..
If this goes well your Photinia x frasieri 'Red Robin', or any other affected Photinia, will look as good as new again later in the year.
Hope this helps.