Dragonfruit

Is it possible to tell what kind of dragonfruit a plant is by looking at the cactus leaves, or are they all identical and only the flower or fruit will tell?

Just a quick bit of research shows that Dragon Fruit is the common name of the fruit of any of several species and 2 (or more) genus of cacti.

It sure ought to be possible to tell which fruit it will be by IDing the plant.

Why not take several pictures and post in the ID forum. Lets see if we can ID the plant. At least to the genus level. Do you have a plant? Or just a fruit?

Things are a little more complicated. Here in Homestead, there are places where dragonfruit cacti are growing wild, actually on abandoned places, and, being frugal, I was wondering if getting a few cuttings from the wild plants would get me started on dragonfruit. For some reason there are a lot of small abandoned properties here.
I have driven by many farms that grow it here and seen how to build a frame for it, so that is not a problem. They use 4x4 posts with rebar at the top.
But googling dragonfruit showed me there are, like you say, different varieties which are different in size and taste. So my question was, can I look at the wild dragonfruit growing along the side of the road and tell what it is? I think it grows well from cuttings.

Most cacti will grow just fine from cuttings.

Get a sample of the fruit from each of the abandoned lots and taste it, then take a few cuttings from the one you like the best.

Take several pictures and post in the ID forum.
Overall shot, and several close ups of as many plant parts as you can:
Flower, fruit, spines and so on. The more details the easier it is for someone to ID it.

There are no flowers yet on dragonfruit here in Homestead. Even the commercial orchards are barren and there is no fruit for sale yet in the markets. Would pictures of the cactus leaves tell anything? I'd rather not wait till autumn to get started, and summer is the dragonfruit season here. Googling dragonfruit says fruit comes all year round, but my eyes tell me it doesn't.

Well, take several pictures showing an overall shot of the whole plant, so we can see the size and shape (something in the picture for size, or just tell us how tall it is)
Several close ups showing a few pads, and the connections, and even closer pics of the spines.

Electrons are free! Post lots of pics!

Well, things didn't turn out so well. The abandoned plants had rot on them, and some weren't so bad, but others looked horrible. I cut some better looking ones, but then I did a little googling about pitaya and rot and the impression I got was that -- never introduce this into your garden. I threw out my cuttings. I recently have been trying to fight black spot on a papaya. The fungus just does not like to give up. I hit it with neem oil once a week, and it simply does not completely disappear. Four weeks now and there are still black spots, nothing like the worst stuff that I had at the beginning, but still some spots. I don't want to do this with pitaya as well. So I need to get smarter about how to start. I suppose if I used some stronger pesticide it might help, but I am gardening so that I won't have pesticides around my food (as well as for the fun).

Well, look at it this way:
Even neem oil is not non-toxic, and you are accumulating a lot of exposure spraying over and over again.
If you used something stronger you might get on top of the problem with fewer exposures, and therefore less overall toxicity than the treatment you are currently trying.

You are right not to introduce more disease problems.

Look into sterile cloning techniques, where you will just take a few cells of the healthiest part of the plant. Might take a while to grow it into a productive plant.

Disaster strikes. I got a bad whitefly infestation on the tree already hit with black spot. This led to papaya leaf curl virus doing a number on the new leaves and branches. They turned and bent at angles, and looked pathetic. We trimmed off all the diseased branches, and now are watching the tree to see if it can possibly recover. I stopped using neem oil, per your recommendation. My neighbor, who is a farmer, said he uses soapy water for whiteflies, and I will try that. But I think the tree is doomed. None of another neighbor's papayas was affected, so I think I must have done something wrong to weaken its resistance. We had a lot of weeds in the yard (we bought an abandoned house) and I think the whiteflies like the weeds and jumped to the papaya, but who knows.

I started some papaya seeds from a good papaya we got at the farmer's market. Maybe I can keep one of them alive... Nothing has sprouted yet. We water them just about every day and look for something to poke up. We are doing the same with a tasty passionfruit.

The papaya tree was pruned drastically but it isn't dead and seems to have recovered enough to grow new leaves. I wish I knew enough about how to nurse it back to health.

The papaya and passionfruit seeds finally broke through the soil and sprouted. I feel a little bit redeemed.

Way to go!
Patience wins out.

Patience is the operative word here. Two weeks later and the sprouts are hardly an inch high. We have them in small bio-degradable cups, very small indeed, and maybe in another couple of weeks we can plant them, cup and all, into a real pot.
We have a nice neighbor who waters them when we go away, but this summer we will move and have no one. Do you have a trick for keeping potted plants moist when you go on vacation?

If the plant is OK with the humidity then make a miniature greenhouse with a plastic bag. No real structure involved- just tie a bag over them with a stick or two in the middle to keep it up off the plants.
Or buy a little kit sort of mini-greenhouse.

Practice ahead of time so you know how much water to add and how long it lasts.

Very interesting! I will check Home Depot for the kit you suggested. I am guessing you put a little pot of water in with the greenhouse and it evaporates and keeps the soil moist - right?

Just to let you know, the papaya tree you consulted with me on has come back to life. The heavy pruning didn't kill it, and all but one of the diseased leaves has fallen off and there are many new ones, and even a flower. Best wishes!