Sticky Leaves?

[blupit007]

Charlie, everyone,

  I have 'The Path' growing as a really bad grafted plant that I got from another vendor.  It was purchased in June, looked awful, and hasn't grown but an inch...  I have it under intense grow lights now since the beginning of October.  It has had some spider mite issues, but otherwise had gotten really green.  I started Kondos 2 1/2 weeks ago as a drench mixed with my fert.  I now have sticky stuff all over the tops and bottoms of the leaves.  No other hib has this issue.  I treat them all the same.  The only other hib that I have in the grow box is a pot full of POH cuttings.  Everyone gets the same fert drench mixed with Kondos.

  Has anyone ever experienced this.  I did pick 2 yellow leaves off of TP tonight, didn't check for mites, but I thought the sticky stuff is strange.  It looks like it sweated, but then dried solid...sticky.  (I don't spray anything on any of my hibs either)

Thanks,
Kristen

[Darkhorse]

I've had sticky stuff on leaves but from what I recall only the bottom of them.  I think it's related to spider mites... they open up a ton of little holes in the leaves and then "stuff" leaks out.  Again from what I recall it was mostly on the leaves that had gone entirely yellow from mite infestation.

[Charlie]

Good question, and one that comes up from time to time.

First off, remember that hibiscus is in the same family as okra, and does contain a lot of thick, sticky sap though not as much as okra. When I did some experiments rooting cuttings in a glass so i could see the entire process that is usually hidden  some of the cuttings would discharge a large amount of thick fluid after being stuck in the water. It was easily visible and surprised me because I never thought of or saw hibiscus cuttings "leak" like that.

So, the question is how does this sap get onto the leaves. Insects are the number 1 culprit, as Jordan suggested. Feeding on the leaves does damage them, and fluids can escape. Or, many sap sucking insects excrete the excess sugars they take in and these fall on the leaves or the leaves below where they are feeding. Sometimes sooty mold starts growing in the excretions which is what the black stuff is that you can see on leaves sometimes. Hibiscus flowers also make nectar, which is what the hummingbirds feed on when you see them around the plants. In some situations this nectar can also drip out of flowers onto leaves but this is more rare.

There could also be other things going on that we don't understand completely. Plants transpire water the way humans sweat, and water condensation forms on leaves when temperatures drop enough. Leaves may have sprays or dust on them that mixes with such water, leaving a sticky residue.

Mostly, I assume insects when encountering sticky leaves. The insects may not even be there any longer but their excretions and damaged leaves remain.

Sorry to hear about your plant of The Path. It is a pretty flower, one of our all time best sellers. Since it does not root well or have the greatest bush we have been trying to hybridize better varieties with similar yellow and pink flowers. Even so it is worth grafting from time to time and I will try to do that.

Charlie