Dear Donnie: When there is growth, whether it's bloom buds or foliage, new roots are emerging to support that growth.
That's why, contrary to much opinion on the matter, I recommend fertilizing very lightly with an appropriate balanced organic fertilizer when camellias of any kind start to bloom.
Once established, camellias need very little fertilizer to be healthy. Healthy camellias are less prone to disease and pests than unhealthy ones.
1. Camellias don't need much fertilizer. They get enough nutrients, in many cases, from decomposing mulches. I have fertilized mine fewer than a dozen times in the 30 years I have been growing them here in the Sandhills. Most of that fertilizing was done when plants were young and still establishing a big, efficient root system. Still, I do fertilize them some years because they seem to be growing slowly, blooming less, or showing higher levels of diseases or insect attacks.
2. Use only fertilizer formulated for camellias or acid-loving plants, such as Hollytone. And don't use very much. A handful or two around a 5-foot camellia is adequate. Such fertilizers are balanced and produce sources of slow-release nutrients that encourage healthy bacterial activity in the soil.
3. Avoid fertilizers designed to be dissolved in water. They are expensive for the amounts of nutrients they contain. They are a lot of trouble, and they are very quick-hitting and short-lived. That means repeated costly and somewhat ineffective applications are needed.
4. Make sure your plant gets plenty of water before you apply the fertilizer. Then water in the fertilizer with a 1/2 inch to 3/4 of an inch of water. Plants that are inadequately irrigated will not benefit from the nutrients. And the fertilizer could damage or destroy the plants' vascular systems by removing water, causing a breakdown in osmosis and possible death.
5. If your plants are mulched heavily, you may rake back the mulch, apply the fertilizer, then replace the mulch with new mulch. Old mulches can harbor diseases that infect flowers and new growth. Discarding old mulches is a good preventive measure. It is especially important to fertilize lightly if you remove the mulch first. Recycle the old mulch by putting it in your compost pile and adding enough nutrients to the pile to get the mulch hot. That will kill diseases and pests in the mulch.
6. Avoid timed-release fertilizers, such as Osmocote.
7. Apply slightly more fertilizer in spring when your camellias begin to produce new foliage. Nitrogen is especially important when new foliage is forming. Nitrogen allows new foliage to become very efficient at converting light to food.
By providing adequate nutrients you will have strong, heavy-blooming camellias.