Griselinia leaves developing black spots!

[Adrianne tully]

Can anyone help. My 3 year old griselinia hedge is developing these black spots! Last week I removed all affected leaves, but they are back again - in abundance! Ive attached a picture. Any idea what this is and what I can do to treat before I have a bare hedge?! Thanks in advance

 

[DirtMechanic]

Purely a guess, but it may be "tar spot' , a fungi common to maple trees. It overwinters in the leaves so removing them for sanitation is good.

 

[Adrianne tully]

Purely a guess, but it may be "tar spot' , a fungi common to maple trees. It overwinters in the leaves so removing them for sanitation is good.

Thankyou - I'm thinking it could be blackspot - another fungal disease, so I've removed the affected leaves, sprayed with a fungicide and will await the results!

 

[DirtMechanic]

Thankyou - I'm thinking it could be blackspot - another fungal disease, so I've removed the affected leaves, sprayed with a fungicide and will await the results!

I kept running into blackspot while searching. The dots were small and spread around.

 

[Sheal]

Welcome Adrianne. Griselinia can be prone to Phytothora which creates similar black patches to yours. Apparently it is currently a problem in New Zealand.

 

[DirtMechanic]

I could not find really good pics of phytothora that closely matched the original photo but found these.

 

[GQTN]

We have found a few leaves on various Grissy plants that look like phytothora - what is the best fungicide to treat ?

 

[DirtMechanic]

Phytophthora?

Potassium salts of phosponic acid. Bonus it is systemic and absorbs via foliar pathways as well as via roots. That oomycete is also known for sudden oak death and is a nasty water mold that will take out shrubbery and other plants and trees around your home. Is your plant staying too wet?