I had notches bitten from the leaves, which I treated in late September with nematodes. There are now tiny white worms that float on the surface if I pour a bucket of water into the pot. They don't look like vine weevil grubs but I can't identify them to know if they pose a threat.
If you don't see any damage, the tiny worms are likely the nematodes you added. Nematodes are difficult to identify by their appearance because they are so small. But aside from the beneficial nematodes you added, there are other harmless nematodes that live in the soil. So if you don't see damage to the plant, there's no reason to worry.
What's eating holes in all the leaves?
Scale pests are the most common, but it could be other pests.
Spray the plant with Neem Oil, it will take care of most pests and is safe for people, pets and bees.
https://www.gardeningknowhow.com/ornamental/flowers/camellia/identifying-and-fixing-problems-with-camellias.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/control-plant-scale.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
I just bought a house with a huge variety of Camellias. The problem I am having is that the camellia is now a tree with a good size trunk. The tree is over 15 feet tall and sits right in front of a window that I can't see out of. The trunk is bare with no limbs for up to 5-6 feet. How can I trim this tree drastically without harming it?
It is possible to severely prune a camellia to entirely change its shape and basically start again. Just after it finishes flowering, you can prune as far back as 1 foot from the ground. Or, if you want a more gradual approach, you can prune it back enough to remove 1/3 of its total size in the first year. This should rejuvenate it and allow you to shrink it to a more manageable size.
Here is how to prune camellia into the future:
https://www.gardeningknowhow.com/ornamental/flowers/camellia/pruning-camellias-how-to-prune-a-camellia-plant.htm
I inherited some limbed-up lanky top-heavy plants. Is it ok to cut them back to 2 feet to encourage new growth at the bottom? They are now about 8 feet tall.
Severe pruning should be done after the plant is done flowering.
You can prune 1/3 or up to 1/2 of the shrub.
My camellia flowers are partially opening - about half way, then they are withering.
Make sure you are keeping the soil evenly moist and that your plant is not in too sunny of a location.
A balanced fertilizer is best.
Nutrient deficiencies can cause leaf, bud and flower issues.
The symptoms you list however may be Bud Mites. They can cause bud drop and the decline of flowers.
They can't be seen with the naked eye, you may be able to find them with a magnifying glass.
Neem Oil is the best treatment for Bud Mites.
Here are some links with more information.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My camellia is about 3 years old, and this year it produced lots of flowers, but the flowers open and look great and then they fall off. Could it be the chilly mornings, or is it something else? I wait to hear from you, many thanks. Regards, Derek.
Yes, cold mornings could be causing your camellia flowers to drop off. Providing too much fertilizer can also cause flowers to fall off. Here are more possibilities:
https://www.gardeningknowhow.com/ornamental/flowers/camellia/camellia-flowers-not-opening.htm
We just bought this house and noticed two trellis trained camellias by our entry. One is doing well but the other is dying, I think. The foliage has thinned out and the stalks have white blotches on them. I have sent pictures, and the last picture is of the healthy camellia just to the side of the unhealthy one. Thank you for any help you can give me.
The splotches on the trunk might be lichens, which are not harmful in themselves but can indicate that the plant is unhealthy.
https://www.rhs.org.uk/advice/profile?PID=411
Check over the plants for any sign of insects on the leaves. You could also add some fertilizer in case nutrient deficiencies are contributing to the yellowish leaves in the photo:
https://www.gardeningknowhow.com/ornamental/flowers/camellia/camellia-fertilizer-info.htm
Here are some other camellia problems you can look for:
https://www.gardeningknowhow.com/ornamental/flowers/camellia/identifying-and-fixing-problems-with-camellias.htm
http://www.clemson.edu/extension/hgic/pests/plant_pests/shrubs/hgic2053.html