Looks like water stress rather than verticillium.

The golden one will have more leaf damage than the others because it's gold, not green nor purple.

They appear to be in the ground; is that correct?

What's the prevailing weather conditions?

And how do you water them? i.e. the method (hand, drip, hose, sprinkler?)

For how long?

How do you determine when you need to water again?

hi Jean,

they are in the ground.

it has been hot and dry.

i water with a slow-drop homemade hose - 150 feet in length with 1/16" holes drilled every few feet - about 3-4 times a week for about an hour depending on weather conditions.

all shrubs are on a 1' berm so drainage is present.

when were they planted...

does the sun hit the cement .... is that side of the plant more affected???

water when the plants need it.. insert finger.. and let near dry in between waterings .... having one system for a multitude of different types of plants.. can become problematic ...

ken

I think you're watering too much...smoke trees require well drained soils. Try running it overnight once a week.

Watering frequency seems excessive but the duration is probably not long enough. dbarron's suggestion is good - water less often but for a much longer period of time. You want the water to penetrate down fully into the soil profile - at least 8-10 inches - and I doubt that is being achieved in just a hour with your homemade system. You may need to do some testing to find out how long the water needs to run with each individual application but the general rule of thumb for irrigation is infrequently but long and deeply :-)

btw, if these smoke bushes were affected by verticillium, they would very likely be dead and not just damaged. VW works very rapidly with these shrubs (also viburnums) and the entire plant would most likely be covered in dried, wilted leaves and virtually overnight. Unfortunately, I see this rather frequently with my consultation business. Japanese maples and smoke bush (Cotinus) are extremely prone to this pathogen in affected soils.

thanks all! this is helpful. i've also read that VW is an aggressive fungus and works fast. i guess i'm not sure this is the case here.

as far as the watering system goes, i adjust the frequency of it depending on the weather. it hasn't been AS hot the last week or so. i actually haven't been using it as much, either. if it rains once a week for a few hours, i generally leave the entire bed alone and let the shrubs and perennials fend for themselves as long as they don't wilt. i try not to water too much so everything establishes deep roots without excessive watering. maybe i'm not giving the smoke bushes enough attention; everything in these beds was planted last year (spring 2015) so i'm only 1.5 years into establishment.

i'll keep an eye on my watering habits instead of concerning myself that this is VW. thanks for your help folks.

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Care of newly planted trees

http://www.ext.colostate.edu/mg/Gardennotes/635.html

Watering newly planted trees

http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/watering-new-trees-shrubs/index.html