It would be helpful to have a few pictures of this plant. Please reply and attach pictures. Any photos are helpful, but most useful would be pictures that show the entire plant in its planting site, the branches lacking leaves, the leaves, etc. Also, how are you taking care of this plant i.e.: do you prune it and when? Is it a plant you planted and did you buy it from a commercial nursery or did it come from some other source? If so, are you sure it is a chokeberry?

Thank you, Julie. I am a Philadelphia gardener helping Minn friends in their golden Valley garden. They do not know the identity or source of this bush. Plans reference high bush cranberry but leaves are I ate. 10 years in situ

"...but leaves are I ate." - not sure what that means.

Chokeberry (Aronia) and high bush cranberry (Viburnum) are two different plants, so it would be helpful to know the Latin name of the plant. That said, this isn't an Aronia. It's likely a Viburnum cultivar (there are many). These are sometimes referred to as bush cranberries thought they are not at all cranberries.

Viburnums are full sun plants and bloom best when planted as such. I asked about pruning / care because your friends may be pruning off the flower blossoms depending on when they prune the plant. Viburnum bloom on old wood so must be pruned immediately after blooming before the plant sets flower buds for the next year (this is the same as lilacs and some spirea). Pruning later or during dormancy (winter) will result in pruning off the flower buds and thus no / few flowers next year.

Without a soil test or knowing the exact plant, I am going to guess the leaf color is symptomatic of a nutrient deficiency. In the spring, your friends should consider feeding it with a complete fertilizer (N-P-K). Feeding it now would prompt new growth that would not have time to adequately harden off before winter. They could do this by applying and watering in a granular fertilizer around the base or pounding in fertilizer "stakes" for trees and shrubs around the shrub root area. Read and follow all instructions that come with the fertilizer and apply at the proper rate and time of year. More is not necessarily better and following the product's directions is crucial to success.

The black edges of the leaves are difficult to diagnose. It actually looks like necrosis (dead tissue) from some kind of mechanical damage (ex: someone came through the area with heavy machinery and banged against those leaves). It may be some insect feeding that has killed the tissue or downy mildew. It could be from excess water due to poor drainage as well. You can see it's hard to tell from a just a picture.

If the damage is just on a few leaves here and there, then I would not worry about the plant's health. If the damage is on one branch, you may choose to prune off that branch. If it is all over the shrub and / or becomes worse, you should send a sample to the U of M Plant Disease Clinic for diagnosis. Instructions for submitting a sample are at http://pdc.umn.edu

 Feel free to reply with additional questions.

Hi Julie, and thank you again.  There was some auto correct that made I ate part of the message!  I am sure the bush is not highbush Cranberry.  We saw some of your collegues at the St. Paul Farmers market Sat who guessed winterberry on the bushes.  However, leaves are hard oblong and smooth edged and there are no berries.  Perhaps need a male, or whatever? We will feed as uou recommend.  Still perplexed as to identity.

Oh! Yes, it could be a large winterberry. This looks more like a nutritional issue. There are male and female winterberry plants (doiecious plants - separate male and female plants; you need both to for cross pollination and fruit). You could have a male plant, but even the male plants have flowers though less significant that the females. It looks like it could be an Ilex verticilata 'Early male' or 'Late male'. You could take a look at the cultivars shown in our Plant Elements of Design plant selection program here: http://landscapeplants.extension.umn.edu/
You'll need to create an account with a user name and password. It's a great program for your friends to select plants and see many MN hardy plants via the 5100 images.