I've had a few that grow like that and I think it has some inherent deformity or virus or something. Sometimes, they grow out of it, sometimes they don't. Are the oldest leaves all normal? If it's something that started along the way sometime - meaning if the old growth is normal, and suddenly it starting doing this, I would whack it back to a set of leaves BEFORE the bad stuff started occuring. The new growth could be all normal after this, though it's not always the case. It's worth a shot. If that doesn't do it, I'd call it quits and toss it in case it has something that might spread to other plants.

Denise in Omaha

It occasionally produces a relatively healthy set of leaves, but there's no point on the plant where all previous growth is healthy. It's still a small plant because it has always had slow, stunted growth. I'm thinking I may just toss it and find another. If it is a virus, I don't want it spreading.

-Chris

I think I'm with you, Chris. I would contact Gardino's and have them reserve one for you when they come available. I think you'll be glad you got a new one because a healthy imperialis is a FAST grower!

Denise in Omaha

Yup, I may have to do that. And it will give me a chance to look for a few others as well. :)

Thanks.

-Chris

Chris,

Have you tried extra Calcium? My two imperialis both get looking like that when I'm not fertilizing enough. Once I started fertilizing more often, the leaves look much better, and it grows much much faster.

Virus always a possibility, although since mine were seed grown, it is less a possibility theoretically.

Renee

It's in a completely inorganic mix, so I fertilize every time I water. I use Dyna Gro's Foliage Pro 9-3-6 (which contains Ca) at 1/2 strength. My tap water also contains about 120ppm Ca, so I don't think there could be any shortage of Ca.

Though I have alternated between using tap water and RO water depending on what I have left in my watering can. That could explain the alternating healthy and unhealthy sets of leaves. Maybe I will experiment with tap water vs RO water, and see how the new growth responds.

I'm still ready to toss it if need be, but if this fixes the situation, it may help me understand potential problems in other plants as well.

Thanks guys.

-Chris

Please keep us updated, Chris. I will be interested to see what your experiments yield.

Can you post a photo of the the whole plant

This is one of the Hoyas that commonly grows in areas where the soils are of a basic pH due to limestone or coral sand. Perhaps the fertilizer solution is too acidic. You could try adding crushed oyster shell or another calcium source to help act as a buffer, at least to stop large swings in pH. Because the media is inorganic it would have very limited buffering capacity.

Mike

Chris, I used to use a fertilizer that contained what I thought was enough Calcium as well.

When I switched to a high Calcium fert mix, it stopped.

I'm growing mine in inorganic media as well.

Now if it would only bloom lol

Renee

My tap water here has a very high alkalinity, a pH of 8 point something, and is loaded with calcium, so I usually use RO water, or add vinegar to my tap water to neutralize the alkalinity and lower the pH. I thought this would work fine on H. imperialis since my Eriostemmas seem to grow quickly with these water sources. They do show some chlorosis on old leaves, though. Maybe I just need to use straight tap water on H. imperialis and my Eriostemmas. The high pH and Ca may be just what they need.

-Chris

Chris, something I noticed recently that leads to me thinking.

In the orchid world, there is a theory that high K and low Ca leads to long term problems in ephiphytic plants. This was based on leaf cutting research.

So a new fertilizer was developed and it is 12 - 1 -1 - 10Ca - 3Mg.

Since my orchids and Hoyas get the same treatment, the Hoyas are being experimented on as well.

I've been using this fertilizer for a couple months now. I haven't seen anything at all in the orchids, but I have noticed my Hoyas are giving me huge leaves compared to past leaves. And this is on well developed plants, not new cuttings. I mean 25 - 50% bigger. Also, the growth is much faster and more developed since I've been using it as well. To the point where I'm like what have you guys been doing the last couple years? lol

Additionally my bloomings this year have been amazing compared to past years, on well established plants, as well as on new plants.

Is it directly related to the fertilizer? I can't say for sure, as I don't grow in a controlled environment, but it definitely leads me to some thinking.

If you are interested in more detail, email me and I'll give you some links to take a look at.

Renee

Renee I am interested to know what fertilizer you are using now. Is it one of the Cal-Mag fertilizer supplements that you add to your regular fertilizer? I guess if it's 12-1-1 then you might just rotate a standard fertilizer with it to supply balanced nutrition for your plants.

Mike

Mike, it's not an official named fertilizer yet. It is a trial version from one specific supplier. If you send me an email I'll forward back to you the links I sent Chris, which explains it all.

Crappy weather here today, but tomorrow I'll try and get some pics showing what I mean about the leaves.

Renee

ok, here are two pics that show the differences I'm seeing. It is more extreme is some plants than others. And I'm only considering well established plants. New ones, of course leaves will get a little bigger as it gets established in it's pot.

Hoya fungii, the center leaf is the average size of all the old leaves. The two new ones I think are obvious - lol This is an extreme case, not all my plants have this much difference.

And Hoya imperialis. The leaf on the left is the typical older leaf, the leaf on the right is typical of the newer leaves. Both older and newer leaves have some variation in size of course, but there is a difference. Photo taken inside, so the leaves are actually much much lighter than the picture is showing.

Renee