New Delphinium arrived with powdery mildew

msqingxiao

Hi all, I bought this Delphinium Magic Fountain Lilac Pink in 1L pot from Gardening Express, but it arrived with what seems to me to be powdery mildew on the leaves. I contacted the customer service and she insisted that the plant is healthy and has been treated. I wanted to plant it out with my two other Delphiniums but I now worry about it spreading powdery mildew to the other two plants.

Any suggestions please?

Dovefromabove

I can't see clearly from the photograph, but white splotches on leaves can sometimes be the result of overhead watering with soluble fertiliser in the nursery.  

However, I wouldn't be planting that out yet anyway ... I'd cut it back by two thirds and grow it on in a pot in a cold frame, to plant out  as a much more substantial plant year. 

Fairygirl

I'd agree with @Dovefromabove - definitely better to grow on. Young delphiniums are very attractive to slug/snail damage when they emerge, and a bigger, stronger plant can withstand that more easily. 
If it is a bit of mildew, just keep it somewhere with good airflow, and it should recover anyway. 

msqingxiao

Dovefromabove said:

I can't see clearly from the photograph, but white splotches on leaves can sometimes be the result of overhead watering with soluble fertiliser in the nursery.  

However, I wouldn't be planting that out yet anyway ... I'd cut it back by two thirds and grow it on in a pot in a cold frame, to plant out  as a much more substantial plant year. 

Fairygirl said:

I'd agree with @Dovefromabove - definitely better to grow on. Young delphiniums are very attractive to slug/snail damage when they emerge, and a bigger, stronger plant can withstand that more easily. 
If it is a bit of mildew, just keep it somewhere with good airflow, and it should recover anyway. 

Thanks both! Hmm my other two Delphinium plants of similar size are already in the ground for like a month but haven't seen much slug damage yet. I've put copper rings around them... I'm slightly reluctant to cut it back though coz there are flower heads showing up already  But will definitely have another think!

Lyn

You really need to cut the flower heads off in its first year, the plant can’t make strong roots and use energy to making flowers,  keep the plant protected from any bad weather through the winter and plant it out next Spring.   

msqingxiao

Lyn said:

You really need to cut the flower heads off in its first year, the plant can’t make strong roots and use energy to making flowers,  keep the plant protected from any bad weather through the winter and plant it out next Spring.   

Thanks Lyn! Will do as told