My Hoya plant moved with me to this address ten years ago, although it is much older than that. It has always been happy in my conservatory, having had over 100 blooms, both times this summer. It is now about twelve feet high and has a spread of about ten feet. Just lately a lot of its leaves have very suddenly turned yellow, mostly they are at the base of the plant although there are a few more dotted throughout the plant. I have never fed it - just gave it rainwater, but now I think it desperately needs some first aid of some sort. Please help.

Red

Repost in the houseplant forum, or even cacti and succulent, @RedScott. I am summoning the experts I can think of for you here. @mjsponies and @plantladylin, any ideas?

I'm not an expert by any means; I'm a very lazy plant caretaker and never remember to fertilize my plants. I've said for years that to survive under my care (or lack thereof) plants must thrive on neglect. I'm fortunate to live in a climate where my hoyas can stay outside year round where they love the heat and humidity.

Yellowing leaves can be caused by many things; too little water, too much water or possibly something is going on from the root level, upwards. Hopefully one of the more knowledgeable Hoya growers will be able to offer advice and tips on what to look for as the cause. Also, the type of Hoya and a photo of the plant in question might help to identify the issue.

I REALLY want to see a photo!

Hoya are epiphytic, meaning they live in a treetop somewhere, their only soil being whatever catches in the roots or tree niches and decomposes. With epiphytes, fertilizer is always a big question mark. I have two: one is over 50 years old and one is only 20 or so. I very rarely think about fertilizing and neither has been re-potted. The over 50 year old is in a pot with soil that closely resembles cardboard but how would you repot a plant like that? Once in awhile, I fill in the voids with fresh soil.

If you can't repot (and I think a very old, very large Hoya fits into that category), than fertilizing is dangerous. Salts will build up in the soil and will affect the health of the plant. When I do fertilize, I mix to at least 1/4 strength (or weaker) and spray the leaves, not necessarily the soil.

As you have not fertilized, salt burn is not the problem. But, mine always lose leaves near the base in the fall and winter - is this just fall/winter leaf fall? If it were, you probably would have noticed before. So maybe it does need a little fertilizer.

Mine also gets yellow leaves that drop on the sunny side of the plant. Has anything changed light wise? If this plant is in a conservatory, does it get a lot of sun? Shade is not good if you want it to bloom but sun is not good either.

I think we need to see a photo of your plant with one of the whole plant (and surrounds) and then some close-ups of the problem areas.

Mom has a Hoya that the leaves have begun to turn yellow she doesn't have fish fertilized like some suggest she does have the miracle grow bloom booster does anyone know will the nitrogen level in the bloom booster help decrease the yellowing?

@Litbear63 - The leaf yellowing is not likely due to undernourishment or lack of fertilizer. I wish it was that easy! Improper water or inadequate light are the likely cause and fertilizer of any kind will not help.

If you post a photo that shows the entire Hoya including its pot we might be able to diagnose the problem for you.

Was perfectly lovely for about 2 years, this year it flowered, then it began to yellow very slowly. Also, leaves seem thinner and wrinkled. All I know is leaves at base are sign of overwatering. Though lots of posts with lots of other reasons. Maybe you can tell by picture.

Do you water Hoya's when dry or even let them stay dry for a while?

Hoyas are new to me but I have a Hoya carnosa, I let it dry out a bit before watering and I have it in bright light.

Have you stuck your finger down into the soil to test moisture level? Does the pot drain quickly when you water? Hoyas are epiphytic; they live in trees, without pots or potting soil. Whatever the medium in your pot, it needs to drain freely and dry quickly. If the potting soil was free draining enough, you could water a hoya daily without any dire consequences - mine are.

They need bright light but not direct sun.

Never fertilize a sick plant unless you see positive signs of nutrient deficiency. Your plant is not suffering from nutrient deficiency. Fertilizer is a stressful for plants. If they don't feel well, its even worse for them (think of having a huge Thanksgiving dinner while suffering from the flu).