Thank you for submitting another photo. This looks like it could be the result of too much water/soil moisture. Leaves will turn uniformly yellow and may show signs of tip injury under these conditions because the feeder roots die and can no longer take in water (or nutrients). This is sometimes fatal to plants, however you can try allowing the soil to dry some and prune back the stems that appear to be dead or dieing (hopefully cutting back to tissue that is still alive). An acid fertilizer may help the plant to recover new green growth after pruning but do not not apply this fertilizer with water at this point. If you do not think this is an overwatering issue, refer to this link for other possibilities. http://azaleas.org/index.pl/azculture.html
Its hard to say exactly what's caused this damage and bleeding, but its possibly Peach Tree Borer. This link has good info: https://tl2q-xvdj.accessdomain.com/webmail/index.php/mail
or it could be a symptom of canker caused by a disease, but we can't say for certain what disease. Disease diagnosis often requires a pathological examination in a lab. The link at the end of this message explains the difference between usual location of borer damage on a tree & canker symptoms, but in addition we recommend you show this photo and any other evidence you can gather, to a local arborist, university extension "tree advisor", Master Gardener group, or some other professional available in your area: http://www.walterreeves.com/landscaping/bleeding-cherry-tree-gum-on-bark/
Diseases are very challenging to identify from photographs, but this might be bacterial leaf spot, a disease that affects foliage in humid, wet growing seasons. It starts as dark brown or black spots surrounded by yellow halos. On the edge of the leaf, turns it white and then brown, and spreads inward, usually on new growth. To minimize spread, water early in the day with drip irrigation. Overhead watering may spread the disease by splashing pathogens. If disease is not extensive, snip off affected foliage and dispose in the trash. When more leaves are affected, cut off as much of the damage as you can and place the pots farther apart. The disease can spread on clippers and other tools, so prepare a solution of 1:10 bleach:water and dip your clipper in it between plants.
Here are a couple of possible explanations for your leaf damage. Cold water on the leaves can cause spots, especially if the leaves were warm when they were watered. It could also be thrips, a tiny bug that sucks the juices out of plants. They often leave black tar-like spots of excrement on the underside of the spots. Here's a link with information on detecting and treating for thrips - http://houseplants.about.com/od/pests/a/Thrips-Managing-Thrips-On-Houseplants-And-Greenhouses.htm Another possibility is a fungal leaf spot disease. The leaf to the left of the photo can't be seen clearly but it might have worse spots. Here's a link to more information about leaf spots - http://www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/DISEASES/leafspotdis.html
It looks like your Hydrangea is having similar problems as your Camellia - possibly leaf tip burn, but this photo doesn't look like Nitrogen deficiency. Both of these plants are acid-loving, and as we mentioned in reply to your Camellia photo, water (and soils) in So Cal are alkaline. This could cause nutrient uptake issues (not enough of certain nutrients, and/or too much of others, causing a toxicity, or tip burn). We've included two more links, one for Hydrangea and one for Camellias that will provide good information about growing these plants, and some of the issues they can have in So Cal landscapes.
Diseases are very challenging to identify from photographs, but this might be bacterial spot, a disease that affects foliage in humid, wet growing seasons. It starts as dark brown or black spots surrounded by yellow halos. on the edge of the leaf, turns it white and then brown, and spreads inward, usually on new growth. To minimize spread, water early in the day with drip irrigation. Overhead watering may spread the disease by splashing pathogens. If disease is not extensive, snip off affected foliage and dispose in the trash. When more leaves are affected, cut off as much of the damage as you can and place the pots farther apart. The disease can spread on clippers and other tools, so prepare a solution of 1:10 bleach:water and dip your clipper in it between plants.
The tips of the Pony Tail Palm often turn brown from over watering, the most common mistake most people make with this palm, or from too much fertilizer. The soil should dry out between waterings. The brown tips can be trimmed off with clean, sharp scissors. As far as what might be causing the damage on the leaves, the damage type doesn't appear to be from any of the more common houseplant pests. Proper watering may prevent further leaf damage. However, you might try to look at the damaged area with a magnifier to see if any pests are present. If you see something suspicious, here's a link to your local extension agency. They have pictures of common houseplant pests as well as treatments for each type - http://www.ext.colostate.edu/pubs/insect/05595.html
First of all, you didn't do anything wrong. This is powdery mildew and squash is prone to this problem. Although you can't get rid of it completely, you can treat it organically so that you can continue to harvest squash the rest of the summer. There are several organic fungicides you can use including Green Cure, Actinovate, sulfur and copper soap. Ask at your local garden center and they can guide you to an organic product. Be sure to spray weekly from now on, concentrating especially on the new foliage and stems, both under the leaves and on top. If it rains hard a day or two after you spray, do it again. Next year start spraying early in the season BEFORE the plant has the problem - knowing that squash and cukes are prone to mildew, you're better off fighting back early in the summer!
Your aloe should do fine outdoors as long as it doesn't freeze - possible by you but not likely. First thing is the soil looks too wet and heavy. I would let it go fairly dry between waterings, just not completely dry. Consider eventually repotting and using some extra Perlite or pumice to loosen up the mix and help drainage. Moving into the sun is a good thing and they rarely have that bright green color when grown outdoors. In fact in full sun they usually take on kind of a bronzey-pink cast to them. They will also grow in a much tighter rosette with the leaves more upright rather than splayed out the way they look now. I would suggest making the move to full sun gradually starting with filtered sun so as to not possibly burn it due to its tender "indoors" skin.
Photo is a bit distant so cannot see the details of the infestation, but are the white markings on the left side of the plant mealybugs, especially if they have a cottony, fuzzy appearance and feel sticky? Mealybugs suck the nutrients out of the plant and will eventually kill it if left untreated. Consult your local garden center for confirmation of the problem and remedies. If they are mealybugs, you can hand remove them with a cotton swab dipped in alcohol and then rinsed off, but if there are a lot, you may want to wash them off with a strong stream of water, followed by a spray with insecticidal soap or pyrethrin product. If this is just a reflection, then the yellowing of the leaves may be due to irregular watering or possibly it is a plant that is sensitive to salts in the water.