I have 3 small--wanted to combine them in a bigger pot
Certainly, just make sure the pot fits them adequately with a bit of room too grow. They do like to have their roots snug; so not too large of a container.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/repotting-christmas-cactus.htm
I put my Christmas cactus out on the deck (it has a roof but gets morning sun) and while the plant seems to be growing, the new growth is red. Is that normal? And how much water does the plant need?
Normally, these do not do well in full sun. It is also necessary to use epiphyte soil, as these will not do well at all in regular potting soil. The red coloration could be due to it getting full sun.
This plant will fare best as a houseplant. I would move it indoors to a bright location. Window light is ok, since your windows will filter out quite a bit of UV light, which is what really harms the plant.
As far as watering goes... They like slightly moist soil. They don't like it dry, and they don't like it sopping wet, so a balance is necessary.
This article will help: https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/advice-for-christmas-cactus-care.htm
My epiphyllums are grown from cuttings from very old, but healthy plants. The original plants were raised in Southern California. I took cuttings when I moved to Charlotte, NC. I had no problems rooting therm and they have grown like crazy over the past 9 years. They live in the screen porch most of the year, but I bring them in late fall til early spring to prevent them from freezing. I have assumed that they don't like being moved, but I do miss those gorgeous blooms! Any ideas? Thank you!
This article will help you.
It can be cleaned off but I don't want it to harm the plant. What is that and why?
This depends on, exactly, how it looks. Two things come to mind. Powdery mildew (somewhat easy to get rid of) and Mealy bugs (Difficult to get rid of)
I will include articles for both, and general care of the plant:
https://www.gardeningknowhow.com/houseplants/hpgen/powdery-mildew-treatment.htm
https://www.gardeningknowhow.com/plant-problems/pests/insects/mealybugs-control.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/christmas-cactus-fertilizer.htm provides a fantastic amount of information and URL's. However, unfortunately, there is no footnote for "a good horticultural soap spray." Please, (1) consider an edit for that; BUT (2) identify one or more examples of a specific product name. AGAIN, it is obvious that 'you' love plants but plant-owners more. It is devastating to have a plant you are nurturing facing death or die! Thanks for all the people who give such detailed advice.
We don't recommend product brands. You can ask friends for a recommendation or try different ones to see what works best for you.
You also can make your own:
Use a natural soap product without synthetic additives or perfumes, which can be found in local natural food stores. Combine one heavy tablespoon of liquid soap to one quart of warm water. Tap water is okay to use, but if you have hard water you may want to substitute bottled water to avoid any soap scum buildup on foliage.
Read more at Gardening Know How: What Is Horticultural Soap: Information On Commercial and Homemade Soap Spray For Plants https://www.gardeningknowhow.com/plant-problems/pests/pesticides/homemade-soap-spray.htm
This cactus is several years old and has flowered multiple times during the year. It summers outdoors in partial shade. We heat with wood and I want to protect it from too much heat.
If it's in bud go ahead and let it bloom. Normally, at 6 to 8 weeks before you want a bloom cycle, you would decrease water and light. Make sure it has 12 to 14 hours of uninteruppted darkness each day and cool temperatures about 50-55 F. (10-12 C). (put it in a room where the lights are not turned on in the evening) It does not need complete darkness.
Here is more:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/advice-for-christmas-cactus-care.htm
My hibiscus tree is aged, few flowers and a hard crusted fungus on the branches. I plan to prune it in the spring then spray with what? I would appreciate you help - Audrey Boston
Unlike counting rings on a tree, I'm not certain there's any scientific way to determine the age of a Christmas cactus, but if the plant has grown large and the stems are woody, you can bet it's been around a while. It may have been trimmed back in the past, which can trigger more growth than one that's never been pruned. Please read our article about how to take care of an old Christmas Cactus.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/woody-christmas-cactus.htm
Certainly, pruning is a good idea for your aging hibiscus. Since there are a number of invaders that like to reside on hibiscus plants, your best bet is to take a piece of branch and leaf to your local nursery to determine what kind of spray it requires.
https://www.gardeningknowhow.com/ornamental/shrubs/rose-of-sharon/rose-of-sharon-problems.htm