Possible Hoya macgillivrayi Problem - Any Ideas?

I've got a Hoya macgillivrayi that I'm having a lot of trouble with new emerging leaves. They begin curling and become deformed. The new leaves get sort of dusty looking with a white waxy dust. When I rub it off with my finger, it seems very waxy, and it appears on both the top and bottom of the leaf. There is no insect activity that I can discern on this plant unless my 46-year-old eyes just can't make them out. The plant was treated with BATS twice over the summer in the greenhouse as a preventative. I never really noticed this problem until I brought the plant inside about 3 weeks ago. I have attached a picture of the entire plant. All the bottom leave are perfect, what ever is happening is only taking place on new growth.

Here is a picture of one of the leaves. It is not all that affected yet, but there is some pitting and the start of the dust. I should have taken a picture of the two leaves that I just lost. I didn't do it, because I was hoping the problem would just go away. The leaves become extremely red and the outer side edges will begin curling toward each other, but usually before that happens there is the white patches of waxy stuff. The leaves that I just lost were about two inches long, but the white stuff can appear when the leave are 3/4 of an inch long.

Here is another small leaf that has the beginnings of a deformity. Does anyone have a clue as to what is going on with this plant? It was repotted about 2 months ago in a mix containing a lot of Coir (finely ground coconut husk), perlite, small amount of peat based potting mix, some bark and clay pellets. I'm really mystified as to what could be transpiring with this plant. I paid quite a bit for this large plant, which had flowered before I bought it. I would hate to lose this Hoya. I am having some difficulty in determining how much to water this plant. I'm not used to using Coir, and it is kind of tough to determine if it needs to be watered. Any thoughts?

Doug

Doug...

I ran into that same sort of problem when I was using coir...had to repot the entire greenhouse (over 3000 plants), lost quite a few plants as well. ESPECIALLY bad, I have found, is the fine coir...as it mats really tight and holds water...which in the case of COIR has alot of salt. The coconut husks are used for coconut milk, then chopped up...this is done on/near the beaches in Asia...and the fine stuff is all the 'sawdust'. Waste not want not!!! I had the devil of a time with it...basically the problem is the salt and even tho I used the fine...and I rinsed and rinsed and rinsed it before mixing it in my mix, it will attract and HOLD salts from the fertilizers we use.

Other growers here have not had that problem...but they don't grow Hoyas. The Orchid growers will not use Coir because of that problem. Perhaps it has to do with being an epiphyte or semi-epiphyte.

Suggestion? Repot your plant, and rinse as much of the Coir off of the roots that you can....

Carol

I agree with Carol, Doug. If you want to add orchid mix to make sure your soil is free-draining, use the orchid mixes that come with tree bark, rather than coir.
Your plant looks pretty healthy and should make it through this.
Ann

Agreed. Coir is nasty stuff. You might even want to use a gentle spray of water to hose off the roots before repotting. Coir just sits in the pot and rots. By hosing off the roots, you can easily find rotted roots and remove them. If you are using a coir mix, that could be a reason you are fighting fungus gnats.
Mel

Carol, and Ann - Thank you! Thank you! Thank you! I never had any idea about the coir. Except for growing carnosas and a couple of other common Hoyas, I'm very new to the hobby. I was starting to get discouraged! I will immediately wash as much of that junk off as I am able to get off. Once again Thanks! You probably just kept someone in the hobby!

Doug

Mel, I just saw your post as well. Thanks, as soon as I get home. I'm washing it off. I don't know why I did not see any of this about coir in any of my research about potting mixes on line. I am so mad. I'm always trying to do the best for my plants, and I make this huge mistake!

Doug

Doug,
The only reason we got the real story on coir is because most of us made the same mistake. It simply takes some time to get the soil mix that works for your growing conditions and watering practices.
Mel

I just read this, and I'm amazed because I've had a very similar problem with my mac. I don't know exactly what is in my mix, because I bought it from Ebay (actually, from someone that many people on this forum have bought the same hoya from)....but I can tell you that I'm pretty positive that there is no coir in the mix. The problem is not anything I was really worried about, since I'm POSITIVE it's not a bug problem. But it sounds like exactly what Doug is explaining (some of the new leaf growth is curled and has some white on it...but the white is not "dusty", it seems to be IN the leaf - if that makes any sense). The plant is very healthy...it's just those few leaves that have that. So I'm not too worried. But it was just interesting to see that I wasn't the only one with the problem. I wonder what it could be if it's not coir (at least in my case)?

Here are some pics:


Gabi

Second leaf with the same problem (there are only 2):

And some new growth that looks very normal:

Salt build up, I would say, Gaby. Some hoyas are especially sensitive: macs, archies, naumanii are some. I would do the same exercise as Doug...or flush flush flush!!!

OH,,, I am going to have to take a look at my orchid mix. No problems so far, but anything I can do to avoid a problem is worth the extra time and effort. I have been pretty lucky so far with not having any major hoya problems--knock on wood! LOL

Well, that was one miserable job, but I flushed all that darned coir away. It took two of us - one person to hold the plant upright, and another person to hold and operate the hose. I wish I could have taken a picture of the mess, but I was otherwise occupied trying not to destroy the plants. I was lucky in the fact that I had only used this mix on five Hoyas. I took the rest of those coir bricks and threw them out the back door on to the lawn! I was under the impression (probably from the coir industry) that coir was the new environmentally responsible answer to peat depletion. It was supposedly the best thing since sliced bread. I was never all that comfortable with the coir mix; I guess that is why I did not use it on more plants - it just didn't feel right.

Gabbi, your plant issue is a little different than mine. My leaves would not even make it to the stage that yours did. Your leaves stay green, mine start out green and get progressively redder until they are a deep maroon color. They curl into themselves, get covered in waxy salt dust and eventually fall off. I would keep cleaning that dust off even using alchohol to wipe it (in case it was an insect even though I new that it could not be), and two days later the "dust" would be back. We probably both have the same issue though - salt build up; yours is just a milder case. I know that I sure feel better now that I've change out the potting mix. I'm sure it will take a while for all that salt to work its way through the plants system, but I'm hopeful that my plant will eventually be clean. The funny thing about this problem is when I first posted about it, I almost did not mention the coir. I'm really glad that I did or may not have found out about it.

Doug

Doug,

It's a good thing you only have 4 more plants to "fix". Is this the only one of the 5 that has shown salt build-up signs?
My leaves don't end up falling off, but I agree that it's a similar problem. I'll have to see what happens. I just don't know where all that "salt" is coming from. There's no coir in the mix and I only use Eleanor's VF-11, which is pretty mild stuff. Oh well...I never really thought of it as a "problem", but after you mentioned what was going on with your mac, it just made me wonder.

Gabi

Your, Gabi, COULD be a fertilizer problem. No enough of the trace minerals... I know that VF is supposed to be complete...but....it never did much for me. Are you using a Miracle Gro bagged mix for them?

Carol

Carol,

I use regular potting soil with all my hoyas (mixed with perlite and bark), so I get the slow-release fertilizer from that. But this hoya is in the mix that Awanda uses...I got this hoya from her. So I'm not sure what's in it. It's growing beautifully...but I just thought I'd chime in since my small "issue" seemed to be similar to Doug's. If it continues, I'll repot. Or maybe I should use a stronger fertilizer? The only thing is, I have been using Eleanor's on all my hoyas for quite some time, and even the ones that have old soil (and therefore the slow-release fertilizer has "expired") have been doing great. Eleanor's has done wonders for my hoyas....they have never grown as much as they have since I've been using this stuff! If it becomes a big problem, I guess I can either repot or use a stronger fertilizer on it...but it really doesn't bother me at all - I haven't lost any leaves or anything, and only 2 leaves have the curling.
Oh, one more thing....I don't know if this matters, but I use Eleanor's with every single watering and also as a foliar spray....so maybe it provides enough of the trace minerals since I use it so often?

Thanks,
Gabi

Gabi...when I used slow release (ONCE!) in my greenhouse, I too got some wierd leaf stuff going on. Osmocote is not very stable...actually, it is very unpredictable as to when it will release. Nutricote is better...and more $$$$$. You 'could' be getting a build up of salts...from the Eleanores combined with the slow release....

Thanks Carol. I appreciate your advice. But I don't use Osmocote. I was talking about the slow release stuff (probably osmocote or something similar) that is already in most of the regular potting soil bags....I don't use "extra" slow release pellets. All my plants have that soil, and this hoya is the only one with the 2 weird leaves. But again, I'm really not worried, because a weird leaf here and there doesn't bother me...it kind of gives the plant character!

Sometimes weird and distorted leaves can come from spider mites. Maybe check for that. Look for webs or shake a leaf over a white piece of paper.
Marcy

Thanks Marcy....already did that, but I appreciate the advice. No mites, thank goodness! I am quite happy that it's not a bug problem, and therefore I will just chalk it up to a non-issue.

I was actually thinking about this, and I came to the conclusion that there are always going to be some hoyas that have some weird things going on. For example...Carol, a lobbii I got from you (one of my FAVORITE hoyas by the way) has this set of curled and tiny leaves on it, and it was there when I received it. Therefore, I know the distortion is not from Eleanor's or Osmocote (i.e., a salt build-up or a lack of trace elements)....it's just one of those weird hoya things! I actually kinda like it :P

Here's a pic of it...you'll notice that the branch on the right has a set of TINY leaves....I think they're kinda cute actually!

[edited to fix a grammar mistake]


This message was edited Oct 9, 2007 10:43 AM

Gabbi,

Many potting soils do not have any added slow release fertilizers in them at all. For instance Pro-mix, which many nurseries and greenhouses use, and my preferred basic soil-less mix, has no added fertilizers. Miracle Grow and Scotts and soils of this type do have added slow-release fertilizers. Some of the Miracle Grow soils such as Moisture Control also have a considerable amount of coir in them as well or at least it use to. I also believe like you that weird leaf anomalies sometime just happen, and it is not worth getting too bent out of shape about it.

Doug

Not to change the subject....but where does one get those wire hoops like is shown in Gabi's plant? I know Carol has them, but I have checked a couple of florist shops & box stores & looked at some plant supply places on line & haven't been able to find them.

You're right Doug....I guess not all potting mixes have slow release ferts in them. And I didn't realize that Miracle Gro moisture control had coir in it....I bought that stuff once and HATED it....as soon as I opened the bag it smelled like mildew and flies were flying out of it! It could've been a bad batch though.

Marcy,
I love those wire hoops that Carol has too. I am planning on placing an order for them from her next Spring, when I buy more hoyas. I've looked around for them also, but can't seem to find them anywhere.

Gabi

I am also looking for those hoops. They work great and Carol is a great supplier for them, but it seems crazy to have to ship such a simple thing all the way from Hawaii. It is one thing when you're placing a plant order, to add them to that order, but to buy them separately, you have to want those hoops pretty bad.

Gabi...you are too right! Some plants just put them out sometimes. Funny, I have an archboldiana which I keep because it is so ugly. The darn thing has grown 2" in 5 years! It has never bloomed and the leaves are extremely 'special needs'. I have grown cuttings of it and they are the same...I have had it tested for virus...nothing!!!! Go figger.

Carol

I have noticed this waxy dust phenomenon on another H. macgillivrai that I have, and found it last night on H. coriacea. I know that waxy dust is a strange way to describe this particular malady, but it is the best description that I can come up with. It is difficult to rub off, and feels waxy when rubbed. Once again, there is absolutely no sign of any kind of insect. I no longer think that it has anything to do with coir being used in the potting mix, because the other two plants that are affected have never been near coir.

My new working hypothesis is that it might be the Bayer Advanced Tree and Shrub that I treated these plants with twice over the summer. I'm wondering if it is possible that these particular plants were over treated, and, or are over sensitive to the product. Maybe the new growth is exuding the stuff from its pores? The plants overall seem to be in good health except for a few deformed leaves, but never the less the problem is a bit disconcerting. I am continuing to flush these plants with lots of water when ever they dry out hoping I will eventually flush away what ever problem they have. Also the "dust" does not readily wash away with water with out scrubbing a little bit. I guess one could say that it is not water soluble. Anyone have any more ideas, suggestions, or thoughts?

Doug

Well that is a thought. I just re treated mine to bring in for the winter, so now I will watch for those signs to see if it might be that.
Marcy

I agree, that sounds *very* logical, Doug!
I haven't used the Bayer this year, so don't seem to have any plants with a similar 'problem'.
Interesting!

Marcy and Nan,

It is the best theory that I can come up with. I'm definitely not fertilizing too much so I don't see how it can be fertilizer salts. My tap water has always produced very healthy plants so I can't attribute it to bad water. So BATS is all I have left. I wish I had another H. macgillrayii that I had left untreated to see if that one remained unaffected.

Well, my H. macgillrayii has recovered nicely from what I will have to call a BATS overdose. I think I am just days away from having it bloom. This is my first big Hoya blossom so I am very excited. It has five peduncles on it with this one pictured being the biggest. It is growing very rapidly; this picture was taken two days ago and the buds are now much bigger and the pedicels (if I remember what Gabi called them correctly) are now over two inches long. I will post bloom photos in the Februaray Blooms thread when they open. Now lets hope that I didn't jinx myself by getting too hopeful.

Doug

Doug - I'm really excited for you - this is one I'd love to see bloom in person!! Keep us posted!

Karen

Thanks Karen!

I will keep everyone posted. It is funny for every success story I have with a Hoya, I also have a spectacular failure. The last of the leaves fell off my H. archbodiana last night so I assume I've killed it. I've also learned that just because you can root something easily does not mean that you can grow it up. I will try that one again though because I've always wanted it.

Doug

Doug, congratulations on your great success with this plant. It really puts my mac to shame. I am looking forward to your upcoming pictures of the open flowers.

Forgive me, but I think I see some white fluffy things in your picture at the base of the pedicels and to the left. I cant tell if they are part of the plant or not, hoping that they are!

Sophi,

No that is part of the plant. There is not a "white fluffy thing" that would dare be on that plant for two reasons: The plant had so much Bayer Advanced Tree and Shrub systemic in its system, it was oozing out of its pores when I first brought it inside from the greenhouse in the summer. The other reason is that I look at this plant very closely all the time, because I am so looking forward to this bloom that if there were a "white fuzzy thing" it would be a dead "white fuzzy thing."

The History of this plant is kind of interesting. I bought it from a woman from Oklahoma on eBay last year for $50 plus I think $15 for shipping (the most I have ever paid for a Hoya). She stated in her add that it had just bloomed for the first time for her and that she was selling it, because it was getting too big for her space. It really was the only Hoya that I have ever bought from ebay that exceeded my expectations. It arrived in perfect condition and was totally wrapped in and around a heavy wire heart shaped trellis. The soil was almost entirely made up of hydroton (small clay balls). I had to use bolt cutters to cut the trellis away so that I could re-pot it. I had it in my small seasonal greenhouse over the summer where it put on five new peduncles, but never did anything else. After bringing it in, white powder began appearing on the underside of the leaves, and I finally came to the conclusion that it was BATS being exuded from its pores. This is after I changed its potting mix from the coir mix that I had it in. It sits in my bathroom with a four foot ,high output, t-5, florescent (108 watts) side lighting it with one grow bulb and one flowering bulb. It seems to like this setup and is growing like crazy.

Doug

All I can say is WOW, Doug. Can't wait to see the next picture. Thanks.

Dee

Doug, I should have known better. I would have been all over it with a Qtip and alcohol for nothing! I dont use systemics so when I see something white it is almost always some kind of bug. Actually years ago I almost killed my first hoya (Australis ??) because I noticed white waxy bumps along the vines. Thinking they were scale insects I scraped them off diligently, until I realized that they were actually emerging roots.

I enjoyed hearing about your plant, and now you have me thinking that I should move mine to a spot under artificial lights. Mine puts out a leaf every month or two and that is all.

This message was edited Feb 1, 2008 6:01 PM

Congrats Doug!! All that hard work paid off!

Sorry to hear about your archi. Mine has done NOTHING since I rooted it from the last David Liddle order. It still looks really healthy, but I'm starting to think it'll never grow a leaf!

Gabi

Gabi,

My archi came from Mel and was the healthiest cutting you would have ever wanted to see. It rooted easily, and then did just what your DL cutting did - nothing. The leaves eventually started to yellow and then just drop off. Now there are no leaves at all. The roots don't look dead, but I don't think it will come back. Does anyone know what the secret is to growing this Hoya? I tried everything I could think of and failed. I will try it one more time, but twice is my limit.

Doug