I believe your first problem was underwatering. Yellowing leaves can also happen with sudden condition changes and is not limited to overwatering.
First off take some cuttings and root them (search within this forum for tips on the how-to).Try to enclose the rest of the plant in a plastic bag (mist plant with water before closing), no vent holes or regular venting required. Keep warm and bright. After a week or two open the bag and remove any leaves that got moldy (those had been dead anyways) and check if the overall health of your plant has improved.

You can not have both underwatering and overwatering symptoms on the same plant at the same time. As Milan says, yellowing leaves can be the result of zillion things, over- under watering but also nutrient deficiency, too cold/hot conditions, too much light, not enough light, pests, disease, etc.
Think of what you have done that might have done this... For example if you just brought it home it might be adjusting to its new environment or to you... BTW, at what rate is it loosing leaves any way? Can you tell us if it's sending out new vines? IF yes, then it needs fertilizer. In order to support the new growth it has to retrieve nutrients from the older leaves.. that's why they yellow (and fall off).. Is it getting enough light? etc. Try to give us as much detail as possible.
HTH

Hi,

Here's some more detail. I brought the HOYA in from grandma's home. it was in the bathroom, caked in dust, and looked like it was neglected too much. maybe her eyesight was so bad she couldn't tell. Well anyway, the window is pretty small and the curtain pulled quiet often, bu she had florescent lights in the bathroom. I don't know how good the light was ewhen she opened the window. Lots of times it seemed to be just a crack enough open to let some light in.
I wasn't there all the time. Probably had lots of humidity whenever the shower was on.

I brought it home in cooler weather but still above zero, but the car was warm, just ran from the house to the car with it.

The leaves are yellowing very slow, in fact, I'm wondering if they were drying up over there. The leaves seemed light green anyway when I brought it here, except for the newer ones. The leaves look dull too.

I washed it off in her shower in lukewarm water. Ir got a good watering in there too probably but I didn't aim for that because I didn't know if it needed watering yet, so I didn't deliberatly take the nozzle and water it up. I just cleaned off te leaves.

I waited a day, and then I checked the soil, it was hard as a rock dry. So I watered it but it spilt out the bottom and I gave up, thinking it must have run right through.

I left it alone for a week. ANyway, the some leaves turned yellow, others are still the same paler green.

I put it in a window that isn't very bright, but I have plant lighting. I have a florescent bulb which is compact, and I got a blue florscent just recently and I have a 400 watt red/orange bulb too, which, all my other plants seem to really enjoy. I used the aquarium bulb to get as much of the blues as possible. I got a regular grow comepant florescent too. So with the 3 bulbs and the outside lighting, there is a good chance everything will get all the light they need.

But I don't know what hoyas really light, shade, medium light or bright...I don't know if these bulbs TRULY help plants so radically, but you tell me. I'd like to know.

There are some dry twigs in in there, I noticed, they sorta snapped off.

thanks!

-Deborah

P.S. the plant is misted and now in a transparent plastic bag. It sure needed a big one! It's back under the lighting system.

It sounds to me like the plant was not getting much water if it immediately ran right out the bottom. Sometimes a very dry soil will pull away from the pot into a hard ball & the water just runs around it & out the bottom. In this case you need to fill a bucket or some container that is larger than the plant and submerse the pot. You will need to hold it down as it will try to float back up. Then you will see it bubble as it absorbs the water into the dry soil.
One good method to tell if the soil is wet or dry is by the weight of the pot when you lift it. Does it seem light in comparison to the size of plant? If so, then you are not overwatering, but instead the plant is in need of more water. Some of my hoyas will get yellow leaves from not enough water too.
It sounds like you have done a good deed to rescue this plant from a dark dry life. It could be that the shock of all your tender care was a bit much for it all at once. Keep us posted on the results of your efforts.
Marcy

Cyberian_Husky
Just wondering how your plant is doing. The same exact thing is happening to me. My Grandmother gave me her plant of 20 years and it is really huge, a monster. But everyday I have been picking one or 2 yellowing leaves off. Some leaves are shriveled like not enough water, but when I checked the vines closer I noticed some had little cracks in them. Must of got fractured during transportation. There was no way to prevent it, it was very top heavy.It was in her living room window with some morning sun, now it is getting really good morning sun, hope it is not too much.
But I can't figure the shriveling and yellowing leaves together. Some vines I have checked thoroughly but I see no cracks at all. The one thing I might have to do is check and see if a main stem snapped under the dirt.
I didn't transplant it I just put the pot in a bigger pot and filled with dirt for added weight to hold the trellis. My grandmother said she watered everday but I can't see doing that seems to still feel a little damp after a few days. Also with the pot in dirt I am sure it can't dry out as quick. But I am rooting lots of cuttings from the broken stems. Please keep us posted! TJ

Hello TeresaJo!

Sure, I'll keep posted. I'm trying the last 2 ideas.

Seems pretty clear to me that old plants don't like to change environments. I guess they end up depending on the situation they are used to, and I guess they grow up to fit into their environment; I guess they are like people. If you move to another city or country, you need time to get used to the place. I know it takes me about 2-3 years to get used to a totally different environment. I guess plants are the same.

Maybe I'll try my best to understand the environment it is was in, which window, how much light, how much humidity, and mimic it.

It'll puzzle me for a while, because I don't think I want to re-coat all the leaves with dust, put it in a darker place, and stop watering it, bu maybe, that's what it's used to and likes.

I don't know! It could also be used to a lot of humidity from the shower, and the floresent lights.

WEll, I'll try one thing at a time. I don't want to try too many things and kill it with kindness.

hello all,

I had soaked the hoya plant in a bucket of water, as well I sprayed all the leaves and kept it in a clear plastic bag for one week with lots of light.

The result is, the plant looks beefier, moistened if you will. The leaves that curled up look succulent and unwrinkled.

Overall there is an improvement. Some leaves darkened, others are lighter green but improved and some I'm sure are going to dry adn fall off because they are too yellowy green to survive.

I have a question:

On some of the bare branches some growth has sprouted, I don't know what it is, but where there were bumps, there are now some white things growing out. I don't know what they are, could they be small leafs that haven't gotten enough light and look white?

Could they be mould? I don't know if mould can do that, I mean, they are pretty pointy looking, but fragile enough to be mould, I just don't know much about mould I guess.

But they come from those bumps anyway. please let me know!

Hi Cyberian,

Could be aerial roots starting to form, depending on what kind of Hoya, sometimes they develop little roots along the stem. If that's what this is, it's normal. I'd said just wait & see for a few days.

Those are Aerial roots as PG stated above.
The high humidity in the plastic bag encouraged your Hoya to grow roots all over the stems and these roots will absorb the water from the air helping re-hydrate your plant.

Happy Holiday to all of you!

Milan