Question
I have 6 new leatherback Viburnum planted in the early fall of last year (2007). I live in Norther NJ.  The plant leaves are starting to yellow and the plant looks stressed.  There is new growth however at the branch tips.  Given the higher than normal temperatures in the New Jersey this past week (4/15)and subsequent budding/blooming of many plants, I hand watered to see if this improved the plants healthy leaf position. It did not.  Is there a disease, fungus or bacteria I should look for and try to tread before it's too late.

Answer
Hi Mark,

I apologize for taking so long to answer; there has been illness in the family, and I have been falling behind.

At this point, I would not be too concerned about pathogens unless you see visible lesions or necrotic spots.  These are strong symptoms of bacterial or fungal diseases.  Viral diseases can cause yellowing of the leaves, but these are not consistent within the leaves, yielding a mottled or streaked appearance of the leaves.  Most viruses are transmitted by sucking insects, and unless you have a large population (unlikely at this time of the year), you probably are seeing some sort of nutrient/environmental problem.  

Give the plants some time to adapt to the higher temperatures and longer day lengths.  If the yellowing persists (and the new growth continues), apply a balanced (10-10-10) fertilizer according to manufacturer's directions.  

Viburnum species grow in a wide range of soils and are tolerant of drought, so I wouldn't rush to water them.

You mentioned that the "healthy leaf position" had not improved.  Is there some unusual leaf orientation?

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