Red Robin leaves turning yellow

[d23]

Hi there,

I was wondering what the cause of the leaves turning yellow on red robin photinia - this is post a week of >30 degrees in full sun in Adelaide. Would it be heat stress, lack of water, fungi or something else? Any ideas on how to treat it?

Thanks so much

[MitchellMc]

The plant looks very healthy apart from those specific leaves @d23. It could be heat stress, but I find it quite unusual that only those leaves were affected, not the more succulent growing tips.

Have you noticed the issue progressively worsening after the hot weather, or has it eased? I'd be tempted to cut those yellowed leaves off and monitor to see if others begin to yellow and report back then.

Mitchell

[d23]

Hi Mitchell,

Thankyou for your reply. I am seeing it on a few other ones which are in direct sunlight most of the day. Where I have a few around the side of the house I'm not noticing any. At the front it's also starting on a few leaves which is in direct sunlight (3rd picture).

Is there any chance it could be Iron Chlorosis that it needs more nutrients?

Thanks again

[MitchellMc]

Have you noticed the issue progressively worsening after the hot weather, or has it eased d23? Since the more sheltered plants at the side of the house are not affected, it adds weight to the theory that it's burn/heat or lack of water related. How often do you water, and did you get out there last week on the hot days and give them a water?

It could be a deficiency. When was the last time you fertilised them and with what did you use? If you haven't fertilised in more than three months, apply a controlled-release fertiliser like Scotts Osmocote landscape.

Mitchell

[bobsmith3000]

Hey bud, mine do this when they need magnesium. Assuming its the same thing, you can water them with epsom salts or get the magnesium chelate that bunnings sells, should sort them out.   

[EricL]

Hi @bobsmith3000, 

Welcome to the Bunnings Workshop community. It's great to have you join us, and thank you for sharing your solution for the Red Robin Plant.

Let me tag @d23 to make them aware of your suggestion. I take it you've come across this problem before. I think it's vital that the nutrients of the soil be replaced to maintain plant health. Using Yates 500mL Leaf Greener Magnesium Chelate is a great way to maintain your plant's green foliage.

Again, thank you for sharing your knowledge about the Red Robin plant,

Eric