Question
What can I do to rid my camillia bushes of black spots?
What can I do to keep Ivy from growing rampant everywhere but it in a controlled area?
What are crushed egg shells and coffee grounds used for on plants?

Answer
Egg shells and coffee grounds.

Crushed eggshells are very useful in the garden. They can be sprinkled around hostas to prevent damage from slugs. They contain calcium, so they're useful to sprinkle in the vegetable garden to prevent problems with nutrient deficiency.

Coffee grounds are another useful addition to garden plants. Azaleas, rhododendrons, blueberries, hollies and other acid-loving plants will appreciate the addition of coffee grounds around their roots. It really makes a great mulch for those plants.

Or you can just incorporate them into beds to increase microbial activity and organic matter content.

Crushed egg shells add valuable nutrients to soil. Calcium is essential for cell growth in all plants. Calcium is especially important for fast growing plants because they quickly deplete the surrounding soil of calcium. Egg shells should be washed before you place them in a compose or into your garden.

Make sure you crush the egg shells before you add them to your garden. Egg shells that are not crushed will break down very slowly.

Ways you can use egg shells grounds in your garden:

Instead of throwing eggs shells away, put them in the bottom of plant pots instead of stones. Egg shells are much lighter than stones and they are a great source of of nutrition.
Place egg shells in a circle on top of the ground surface around tender plant stems such as peppers, tomatoes, broccoli, cabbage to deter slugs and cutworms.
Place egg shells in the soil near tomatoes. Calcium is very useful to tomatoes because the extra calcium will help prevent blossom end rot.
Can egg shells be used along with coffee grounds?

Yes. Egg shells provide calcium to your garden while coffee grounds provide a high content of nitrogen to your garden. Calcium and nitrogen supplements (egg shells and coffee grounds) will help keep your garden soil and plants healthy.

Camilla spots--

Sounds like tea scale. These can be controlled in the spring using an insecticide.
The most common insect pests of camellia are scales. Scale insects feed on plants by piercing plant tissue and sucking sap. Scales do not look like typical insects. They are small, immobile and have no visible legs. They vary in appearance depending on species and sex. Some look like small fish scales attached to the plant. As a result of their unusual appearance, populations can reach damaging levels before they are noticed.

On camellia, scales usually attach to leaves but some species also attach to stems. Their feeding weakens the plant. With a heavy infestation, symptoms include yellowing of the upper leaf surface, fewer and smaller blossoms, leaf drop, twig dieback and sometimes death.

Tea scale is the most serious scale insect on camellia. It attaches to the underside of leaves. Tea scale has an oblong shape with a ridge down the center parallel to the sides. It is a small scale with the female about 1/20 inch. The male is about two-thirds the size of the female. The females vary in color from dark brown or gray to nearly black. Males are white. The female lays 10 to 16 eggs, which remain protected under her body until they hatch. In one to three weeks, bright yellow immature forms called crawlers hatch from the eggs. A typical symptom of tea scale infestation is yellow splotches on the upper surface of leaves. With a large infestation, the undersides of the leaves are covered by a cottony mass.

Controls: With a light infestation, scales can be scraped off the plant and discarded. If only a few leaves are infested, hand picking and destruction of infested leaves is very effective. The best time to spray with a refined horticultural oil (Bonide All Season Spray Oil, Ferti-lome Scalecide, Green Light Horticultural Oil Spray, or Ortho Volck Oil Spray) is in spring, after the plants have finished blooming and the danger of cold weather has passed.  This will kill many adults, crawlers and eggs by smothering them. Spray two applications, 10 days apart. Spray when temperature are between 40 and 85 degrees.

Most insecticides are effective only against the crawlers. In addition, using an insecticide against scales can result in the deaths of naturally occurring enemies of scales. As such, insecticides should be avoided unless the camellia is very valuable.

Monitor the crawler emergence with sticky cards, tape wrapped around a branch, or by putting an infested shoot or leaf into a baggie and watching for crawler movement. Crawler activity often coincides with the flush of new plant growth in the spring. However, some scale species may have overlapping generations with an extended crawler emergence period, such as along the coast.

Insecticides labeled for homeowner use against tea scale crawlers include acephate (Ortho Japanese Beetle Killer), malathion (Ferti-lome Mal-A-Cide, or Hi-Yield Malathion Insect Spray), cyfluthrin (Bayer Advanced Garden Power Force Multi-Insect Killer), and carbaryl (Sevin 50WP or Ferti-lome Carbaryl Spray). As with all pesticides, read and follow all label instructions and precautions.

Ivy
The best way is just keeping the ivy pruned back. If you mulch areas that you do not want it in this seems to keep it out (6 inches deep of mulch). To rid it completely from an area use a herbicide spray
Manual, mechanical and chemical control methods are all effective in removing and killing English ivy. Employing a combination of methods often yields the best results and may reduce potential impacts to native plants, animals and people. The method you select depends on the extent and type of infestation, the amount of native vegetation on the site, and the time, labor and other resources available to you. Whenever possible and especially for vines climbing up trees or buildings, a combination of cutting followed by application of concentrated systemic herbicide to rooted, living cut surfaces is likely to be the most effective approach. For large infestations of ivy spanning extensive areas of ground, a foliar herbicide may be the best choice rather than manual or mechanical means which could result in soil disturbance.

Systemic herbicides like triclopyr (e.g., Garlon?3A and Garlon?4) and glyphosate (e.g., Accord? Glypro? Rodeo? are absorbed into plant tissues and carried to the roots, killing the entire plant within about a week. The evergreen nature of English ivy means that it continues to grow through the winter months although at a reduced rate. Herbicide applications can be made any time of year as long as temperatures are above 55 or 60 degrees Fahrenheit for several days and rain is not expected for at least 24 hours.
Mulching may be an effective choice for smaller infestations when herbicides are not appropriate. Cover the entire infestation with several inches of mulch. This may include wood chips, grass clippings, hay or similar degradable plant material. Shredded or chipped wood may be the best option since hay and grass may potentially carry weed seeds. Covering the area with cardboard may improve the effectiveness and longevity of this method. The mulch should stay in place for at least two growing seasons and may need to be augmented several times. Mulching can also be done following herbicide treatment.