@JMJ 4Life Really sorry to learn about your tree. I assume some part of the root mass is fused, so the soil/root mass remains intact like so: If the answer is yes, unpot the plant and set the root/soil mass on a stack of newspapers, rags, old towels, dry sponges - something that will PULL excess water from the soil. Allow it to rest on the wicking material for an hour or two before returning it to the pot it fits. Use a wooden "tell" to "tell" you when it's time to water, because with no water loss from foliage, the plant will require very little water. Using a 'tell' Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant. Watering in small sips in order to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions - which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma and creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor. In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water. Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'. One of the most reliable methods of checking a planting's need for water is using a 'tell' (more reliable than a 'moisture meter'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) works better. They usually come 48” (120cm) long and can usually be cut in half or in several pieces, depending on how deep your pots are. Sharpen both ends of each tell in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell's tip comes out nearly dry. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue. Al

I believe that all the mosses that are being sold as aquatic mosses are actually mosses that occur naturally in very wet places or near bodies of water. The only moss that I would tend to call entirely aquatic is Fontinalis but even that may be found emersed. Your best bet is to try the one you like best and see how it performs. Not really into ferns and fungi.

Hate to sound dense, but what do you mean, under a retaining wall?

I don't have any advice about overcoming your phobia that hasn't already been given here, but I wanted to chime in that there is no rhyme or reason to phobias, so it's not helpful for others to say "that phobia makes no sense". I have always had pet fish and I adore them. I have no trouble letting them nibble on my hand as I clean their tank, etc. I can swim in ponds with little fish darting around, and I have swum in the Gulf of Mexico with harmless sand sharks bumping around in clear view. But I am very unhappy about visiting aquariums where there is just a wall of glass between me and big fish. And (thank you, Diana Gabaldon) I am freaked out swimming in lakes because I am afraid of . . . the Loch Ness monster! Yes, I know it is ridiculous to be afraid that the Loch Ness monster is in a lake in the US. And even if the Loch Ness monster WAS in the lake, it's probably a harmless vegetarian and wouldn't bother me anyway. After all, I would PAY to swim with manatees, so why be leery of Nessy?Because knowing it is ridiculous intellectually isn't the same thing as not being filled with heart-pounding dread when you're at the lake!