Adenia glauca care questions

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Originally Posted by Arizona Jeanie

...Adenia glauca [leafed out].... The leaves are all chlorotic--yellow leaf tissue between green veins.... Is it OK to fertilize aggressively, now that there are leaves and active growth? I'm thinking an all-purpose complete fertilizer for acid-loving plants. I'm inclined to Jack's Petunia Feed, as it is formulated with micronutrients and iron, in case that is the problem.

...Should it be repotted when it is dormant or actively growing or somewhere in between? Also, how do I make a succulent mix that is more acidic but still fast draining?

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Originally Posted by Arizona Jeanie

Two new questions have occurred to me.

When repotting, do you try to keep the caudex at the same level with the potting mix, or do you raise or lower it a bit?

When speaking of toxicity--is it like euphorbia, causing irritation and burning with contact? Or something else? I'm allergic to latex, I get a skin reaction to a lot of plants that have latex-related sap.

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Originally Posted by Arizona Jeanie

...The plant is in a pot, in unknown medium but it seems to be remarkably hydrophobic whatever it is. Someone who worked there before me recalls it being there for at least five years with no attention. I've found a number of succulents there not doing well, potted in poorly-draining, compacted houseplant mix, some with a large amount of small-particle sand clogging the bottom of the pot. They compensated for this by only lightly watering the surface, apparently a common misconception about succulents. Also, this Adenia being severely chlorotic makes me suspect it needs proper medium to develop the healthy roots needed to absorb nutrients. I'd like it to be able to utilize the increased watering and feeding I'll be giving it. I have not seen the roots.

The greenhouse is tied into the circa 1910? steam heat system that serves the entire VA complex. (I'd like to see the boiler, but that's another story.) Temperatures are not tightly controlled, but seem to be staying between about 55 and 70F through the winter. There's a bit of a steam leak (or something) that keeps the humidity high all winter. I can't do anything about that, except by withholding water from the few winter-dormant plants.

In summer, the greenhouse is served by somewhat creaky evaporative coolers. Again, temperatures are poorly controlled, getting close to 100F at times, but it does keep the humidity up. I don't have an exact number.

The slightly warmer weather a few weeks ago, and slightly longer days seem to have triggered the spindly, chlorotic top growth, so I think it's time to start the increased watering and feeding.

Do you have this plant yourself? It doesn't seem to be common in cultivation, I can't find much information online. It took me a couple of weeks after the leaves came out to even identify it, but I'm pretty certain I have that right. I have no idea how it ended up in the greenhouse, but we do get donations of plants people are no longer able to care for, for whatever reasons.

I'm very grateful for any and all information and detailed recommendations you can share with me. I'd like to see those rampant vines this year....

I don't have it now. I don't have an area humid enough in the summer to keep Adenias happy. They survive but barely grow. In the US Midwest like St Louis they are rampant. They don't need any humidity in the winter, when they are dormant and leafless, but they tolerate it.

They are deadly toxic if eaten or used as arrow poison, not on the skin. Some people may have sensitive skin, as with other passion vines. Unfortunately they are not toxic to insects.

I suspect the greenhouse is getting a lot warmer on some sunny days than 70 F / 21C. Otherwise it would not have sprouted yet. Adenias generally sprout fairly late in spring, after many other caudiciforms have sprouted.

If it's going to be sunny during the days for a while, then I would repot now. Most people use something with 75% or more inorganic material, like pumice, large gravel or large perlite, and water frequently during the summer. This dries out rapidly in fall when the plant is going dormant. It is at risk if it's cool and the soil is wet. If you can get pumice or cinders that would be best - it would make the pot heavier, and less likely to tip.

You can use straight high-quality bagged potting soil if you are willing to repot every 2-3 years, dry it out completely in late fall, let it drop its leaves and go dormant, and make sure it stays dry through the cool months. Potting soil will stay moist longer during summer, when it should never dry out, and you won't need to water as much. I use 75%+ pumice or large particle perlite mixed with potting soil for plants like this because I don't always have time to repot when I should, and such media last many years.

Because this is a rescue, and you're getting used to the plant, choose a pot about 4" / 10cm larger in diameter than the current pot. Don't use a shallow pot; a standard depth is fine for now. In the future a deep pot will allow more caudex growth, but again we're in a rescue situation. Repot to the same level for now. People do raise the trunk, but I wouldn't stress this plant now.

Unpot it dry. Gently remove as much old soil as you can, even if you need to spray it off with a hose. Repot into the new soil. Let it stay dry for a few hours, then water once heavily with a fertilizer solution.

The chlorosis might be from iron or magnesium deficiency, but perhaps nitrogen deficiency. These need a lot of plant food. If I had time I would use something like 1 tablespoon / 15ml of 20-20-20 with micronutrients per gallon / 3.78 liters of water at nearly every watering. The plant grows faster the more you fertilize.

Water before it wilts. With a repotting and watering it will soon make new roots. It will be able to suck all the water out of a pot within a day once it gets going. The tops are very skinny vines that need something to climb on. If you keep cutting off the tops, like a lot of growers do to keep it small, the stem will hardly increase in size.

As long as humidity is high and it has plenty of water, it won't be bothered by high temperatures. I might worry when it gets over 130 F / 54C. Don't let it be moist and under 60 F / 15.5C. The tops will tolerate full Arizona sun through a window, but the caudex might sunburn. Take precautions against that.

Watch out for spider mites on the undersurfaces of leaves. Passion vines can be index plants for spider mite infestation.

In fall, before nights start getting towards jacket weather, stop watering and let it go dormant. The stems will die back. After the plant is fully dormant you can cut back to just above living tissue.

Your plant might flower. Adenia are dioecious (individual plants produce flowers of only one sex), so you won't get fruit. Flowers are tiny and not much to look at, but let you know the plant is happy.

Oh, and woody cuttings will root during warm weather. People dip in rooting hormone and put them in pumice. Keep in high humidity and heat, and water daily. Most take. They don't reliably form caudices, but this is a way to get another sex of a much rarer species into your collection to set seed without paying half a body for a seedling of known sex.

If you take photos of the other unknowns I might be able to help.

[Arizona Jeanie]

Wow, ES, thank you so much!
This is enormously helpful. Maybe you could post a care sheet at CACSS, I might not be the only one looking for all this.
I'm not particularly interested in propagating at this point, I'd just like to see it get healthy. My only minor question is--wouldn't cuttings grow into plants of the same sex as the parent? Maybe I'm not understanding that part.
We're in the midst of a cold and cloudy snap right now, so I think I'll wait a few weeks before repotting. That will give me time to get an appropriate pot, I'm thinking standard terracotta will be best for now. Does this plant have a taproot, or does the caudex tend to extend underground?
I do now have some pumice--from General Pumice Products, 3/8 inch. I'll put that to use.
I may have to up my volunteering from one day a week in order to make sure this is properly watered through the summer.
Thank you for your kind offer on ID'ing other plants, I'll see what I can do.
I'm planning a weekend in Tucson soon, any suggestions? I'll visit the Sonora Desert Museum of course, also planning a stop at B&B Cactus Farm.
Thank you so much, this is so helpful.

[Arizona Jeanie]

Here are a couple of pictures, to the best of my ability. This is without repotting. I gave it a thorough watering and feeding today, it's grown several inches since last week.

[Dollythehun]

Would you like me to send you some actino iron? It's basically powdered iron. I used it on my petunias with great success.

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The pot size is fine now. I would repot into the same pot.

The chlorosis is from lack of nitrogen, moreso than lack of iron. Adeniums take up everything better near neutral pH, so this might also be part of it. I would use any 20-20-20 with micronutrients, and add a tablespoon / 15ml of table vinegar or apple cider vinegar per gallon / 3.8 liters.

There are much rarer Adenia species grown by succulentists. They are sometimes in the range of $100-$250 or more for unbloomed, therefore unsexed, seedlings. Mature plants can be very much more expensive. Only seedlings develop a nice round and huge caudex. Cuttings develop a thickened stem, and grow fine, but don't develop the round caudex. People will sometimes sell cuttings from these expensive plants of known sex. In this way a person can buy both sexes for much less money than buying sexed plants with caudices, and produce their own seed. A plant could go from seed to the size of your plant in 3-5 years with good care.

[Arizona Jeanie]

Thank you, Dolly, for your kind offer. I'm using a fertilizer that has micronutrients, including iron, so I think it will catch up over time. I'll try the vinegar trick too. Iron chlorosis is a common problem in certain landscape plants in this area. It's not from a lack of iron in the soil but because the soil is too alkaline for the plant to utilize it.
ES, thank you once again. The fertilizer I'm using is 20-6-22 with micronutrients. Supposed to be formulated to help with iron absorption, so I'm thinking it's a bit acidic already. I'll try a little vinegar, see how that goes. Do you think I need to add more phosphorus?
I find it so interesting that plants grown from cuttings don't develop the large caudex, but seed-grown plants do. One of life's little mysteries I suspect. Thank you for the clarification on all that. I didn't know there are "succulentists" in this world, I'm glad to hear it. Just curious, but what species are the rarer and more sought after (i.e. expensive) Adenias?

[Arizona Jeanie]

I repotted in 2019, using a very gritty, fast draining succulent mix with very little organic material, in a terracotta pot. In 2019-20 I fed it lots of Nitrogen/all purpose fertilizer. Added soil sulfur to the pot. Added vinegar. Never could get the leaves to green up completely.
We were locked out of the greenhouse early in 2021. When we got back in this year, I was very happy to find the Adenia still there. When it leafed out, it was again chlorotic. I'm feeding it weekly with 30-10-10 "acid loving" fertilizer with micro nutrients, plus a small amount of cal-mag.
I decided to try something different for the chlorosis, got some chelated iron, mixed it up with a little spreader-sticker, and soaked the leaves. Bingo! Finally the leaves greened up, chlorosis is resolved. I'm continuing the weekly fertilizer, and iron spray every month.
The plant's looking pretty good now. Thanks for all the good advice!

[Arizona Jeanie]

I think it's happy now--it has flowers, and leaves are green!

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Yay! It looks like a girl!

[Arizona Jeanie]

Other than gluing a pink bow to its bald caudex--is there some proper botanical way to add the plant's sex to the label? Someday someone else (not me) might want to find her a mate.
With all the bad news in the world, it made my day to see flowers and green leaves.
Thanks again ES for all your help with this plant, you're a great resource to have available!