Hi, You sound like a really good kid! Your Mom must have taught you well OR you inherited lots of good empathy genes from her. Awesome! The internet says that Fothergilla can live a long life, are relatively maintenance free and pretty disease resistant. Good to know.
I've never grown a Fothergilla or even seen one so I don't know how helpful I can be but I'd like to ask a few questions. In these situations you always go down the list of relevant factors to assess what matters and what can be ruled out quickly. This usually, BUT NOT ALWAYS works for me. Perhaps your answers can provide some clues and someone more knowledgeable might come along to help. Here goes.....
How long has Mom been friends with these plants? A month? A year? Ten years?
Have they ever done this before"
When did this start happening? Suddenly or slowly? A month ago, 6 months ago? Did it start after the temperature rose?
Are they getting plenty of water? When did she water them last? I know they often live near water and bogs and like lots of it. Some of her plants might be getting more water than others. Has she put her hand down into the dirt to see how dry they are a day after they get watered? Has she tried pouring on the water for a few days to see if anything changes?
There's a lot going on in the pictures. (And the pictures are GREAT by the way, helps a lot) Are the leaves slowly turning yellow and then brown and then the branch dies? Or am I just noticing other plants in the pictures? Or is this happening very quickly?
Internet says they need slightly acidic soil and very little fertilizer. But the pictures show (I think) very light green new growth which may be a bit yellow with possibly green veins which suggests that they could really use some fertilizer. Or it could suggest way too much water in that area.
Are the plants putting out new foliage at the same time that other branches are dying? That matters a lot!
Hey! I'm guessing you weren't expecting a pop quiz when you asked this question. But all of this info matters. If it were my Mom, I would ask her all these questions. Then I would suggest that she cut out all the dead foliage on the shrubs. The dead branches can't help the plants but can rot and start a new fungus infection. Then she can monitor how quickly it is still happening by the new growth. I have several plants that let older branches die off each year which is perfectly normal. If the ground is dry the day after she waters I would tell her to dump on the water for a week or two and see what happens. And if the brand new foliage is growing out pale green/yellow I would give it a shot of all purpose fertilizer and see what happens. I don't believe any of these things will hurt the plants and they just might help solve the problem.
There are still oddball things that can be happening like viruses or bugs or fungus but this is a place to start. And I'll probably think of 5 more oddball things it can be as soon as I post this! Or some smart person who has grown lots of these might read your answers and have better suggestions. I wish both of you all the best.
Debbie
