Also, I cannot tell from your pic, but do you have them in containers with drainage holes? They don't like wet feet (well, some do, but not the majority) so move them into pots with drainage holes.

I've only ever fertilised them with slow release "all purpose" pellets, which they had a dose of not long ago but I will try some MiracleGro and see how they go, thank you! Do you think there is any chance this may be a case of over fertilising? I only ask as I was not the last one to give them a dose, my boyfriend was and while I gave him pretty clean instructions of how much to give, who knows how well he listened!

I've got them potted in a hoya mix bought from a speciality nursery (I think it's quite similar to bonsai mix, very free draining and with some gravel-ish type material) and they've always seemed to thrive in that. I have been watering the larger plant a lot more than I used to, as its growth seems to have really picked up (it was moved about 6 months ago to be closer to a window, so has become a lot more active since) but its pot allows for any excess water to drain right out and I never water more than once a week. In saying that, this wrinkled appearance usually only occurs when I underwater and I have definitely not done that, so I assume it certainly could be a sign of a root issue, would you suggest just keeping an eye on them and taking another look at the roots if things don't improve in a week or so?

I repotted the larger one only yesterday and the roots all seemed to be in tact and a normal colour, though I'm not sure what I would be looking for other than obvious rot to identify the issue?

Thank you very much for the reply too! :)

Is the granular feed slow release? If so, you only apply that stuff once every 3-6 months. If not, I have never heard of it. I only know of time release fertilizers, water solubles, and foliar feeds. I couldn't offer any advice, if it is not one of those three, but perhaps someone else can help.

Believe it or not, overwatering can also cause leaves to look dehydrated. Cells either get really full and have edema (the leaves swell and get pitted and ugly in appearance), or they get so full, they collapse, which makes them thin out.

Add a teaspoon of epsom salt to a gallon of water and feed them just ONCE with it. See if that greens up the leaves.

Healthy roots appear in a vast array of colors in hoyas, from white/ivory, to green, yellow, orange, and tan. They should look firm with no fraying (see pic 1), should have an earthy, dirt-like smell, and should not be mottled, slimy, foul-smelling, stringy, or moldy (with the exception of some natural fungi, like mycelium).

Pic 1 (not a hoya, but with orchid roots, you can really see what is going on...not my pic, google image); the fat roots (what is left of them) are healthy, but on their way to death. The stringy roots are where rot or something has happened, taking the healthy outer layer off. In hoyas, this is noticeable, but on a smaller scale. Roots will appear "skinned", with parts of the outer root either missing or cracked/split:

Pic 2 is dry rot. Roots will appear brown and stringy. Stems will also appear brown:

Here is a link to a pic of healthy, happy hoya roots:

http://forums.gardenweb.com/discussions/1968893/can-you-say-rootbound

If there is no improvement or things decline, make cuttings and start fresh.

I'd go ahead and make cuttings of some of the healthier parts of the plants, just in case.

Please, too, make sure you are not having a spider mite issue..You will not see them unless you use a magnifying glass and look under the leaves...The mottled look was a classic symptom in mine in the past..Also, under watering causing root death and then watering is a big problem with these plants..You must water only when they are about to dry out, not when they get bone dry and use a very porous mix that allows you to water more frequently without fear of rot while passing oxygen into the root zone each time..Too, you can't afford to use a mix that holds salt deposits from slow release fertilizers or any for that matter or your tap water...I would make it a practice to take them to the shower and shower them off leaving the water to run through them freely for a few seconds...They LOVE a good pretend rain shower that cleans the leaves off while at the same time pushing fresh water through the roots zone.

Mike)

Could this be the roots coming out of the bottom of the pot that my Hoya is planted in. It is black and very shiny. Or did an animal crawl in and couldn’t get back out.

This conversation is 4 yrs old. Sorry, but what are you talking about? Can you pls post a pic so we can try to answer.

Wow this is an old post but it looks like scale insects me.

The 5th pic down has scale. I know this is an old posting I would love to get an update.