Could it be cause by a disease or fertiliser burn because I spread about a handful of Growmore granules around the roots in early March.
I'm not able to enlarge this image and can't really get a good look at the plant or any detail on the leaves.
Yes, over fertilizing a plant certainly can lead to burns or plant die off.
Leaf fungus issues or bacterial disease can also be an issue with a plant in the description you give. Clean up any dead plant material around the plant and dispose of.
Avoid overhead watering.
These links will help you determine if you have pests or disease and how to treat them.
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/diseases-affecting-viburnums.htm
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/brown-viburnum-leaves.htm
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/pests-affecting-viburnums.htm
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/leaf-curl-in-viburnums.htm
There were no signs of disease last year, but this spring all 3 viburnums are not budding. They have an occasional flower but most of the plant is leafless
It appears to have cankers, which would suggest that there is an infection at the root zone. Usually, by this point, the damage is significant, and hard to control.
I can recommend a treatment that may help, though.
Using DOLOMITIC lime and WETTABLE sulfur, in tandem, can help kill off infections in the soil. Just apply to the soil as per the instructions, and you should see some sort of recovery by next year.
Doing this once or twice per year is a really good preventative method, as well. It also provides essential nutrients such as calcium, magnesium, carbon, oxygen, and sulfur.
This article will give you more information on root infections: https://www.gardeningknowhow.com/plant-problems/disease/root-rot-in-garden-plants.htm
Bushes are 4 feet high. Planted one week ago. Temperatures in the 30's.
If it has budded out; I would say yes...no harm in covering for the overnight hours. Then uncover as soon as temps rise.
viburnum leaves turning yellow
This article will help you assess the shrub.
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/viburnum-leaves-turning-yellow.htm
Hello, All 3 of my Viburnum Cardinal Candy (Viburnum dilatatum 'Henneke') have many of the leaves turning brown from the outside edge going inward, curling and becoming crispy. Planted on 4-20-2018. Any help would be appreciated. Thanks, John
The type of drying that the photos show appears to be from desiccation/drying. That can be a result of water-deficit/drought-stress or fertilizer burn. High Nitrogen, high salt index chemical fertilizers can desiccate roots and therefore restrict uptake of water. The extremes of the leaf tips and leaf margins dry up first. If the condition is severe the drying can continue into wider scale leaf burn and die-back.
This link is for an article on viburnum leaf browning, for your general information. But I don't believe your plants are suffering from any of the fungal disorders indicated.
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/brown-viburnum-leaves.htm
I have a bush that I would like to transplant, divide, and trim, but don't know when is the correct time to do it? Can any one identify it from attached photo?
It may be a variegated viburnum (V. tinus ‘Variegatum’) which should be evergreen in your zone 7. To be sure what it is, I would wait and see what the flowers and/or berries look like for a positive ID.
It looks like someone has been trimming it, probably because they can get up to 12 feet tall and wide if not pruned. Instructions for pruning are included below. You can transplant in spring or fall, see tips below.
My next guess would be a variegated lacecap hydrangea, but they don't require much pruning.
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/variegated-viburnum-plants.htm
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/viburnum-pruning.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/transplanting-trees.htm
This is a follow up from 7-5-18. My Viburnums Cardinal Candy leaves are still turning brown, curling & drying out. I have been giving them lots of water & providing shade.Some new leaves are yellowish green.Is there anything I can do? Or is this a lost cause? Thanks. John
Fungal disease may be to blame. Back off the frequent watering and treat with a fungicide. Yellow leaves can be a symptom of overwatering.
https://www.gardeningknowhow.com/ornamental/shrubs/viburnum/brown-viburnum-leaves.htm