Expert: Christopher Littrell - 9/8/2009

Question
QUESTION: My asian pitcher plant, which was purchased from Saracenia Northwest,is growing in a rock garden. I have kept it in a tupperware tray watered with rain water for nearly two years. Also residing in the rain water-filled tray is a sundew plant. Over the past week or two, I am noticing that the leaves on my pitcher plant are turning yellow from the bottom up. All of my plants are in a south facing window and thriving. when I did some manicuring today, I noticed that the sundew has sprouted several baby plants on the rock that the sundew is living on! I hope I'm not losing my pitcher plant. I didn't notice any bugs when I cleaned out the water tray, which had a lot of algae in it. Is there anything I need to do? I am not fertilizing. Thanks in advance for your help. I appreciate it.

ANSWER: Hello Rochelle,

Yellow leaves do occur naturally on Nepenthes from the bottom up as the plant grows. The older leaves at the bottom will die off, first turning yellowish and then drying out and turning brown. The thing is, you are seeing this yellowing for the first time in two years apparently, so it is something occurring to a degree it perhaps should not. Plants leaves yellow for several reasons, old age, or too much or too little sun, water, or nitrogen. Since you are not fertilizing, we can rule out nitrogen. Since the plant has been in the same window for two years as you indicated, we can rule out light. So I would say that the plant might be getting too much water since Nepenthes roots can asphyxiate in standing water and begin to rot. Try getting the Nepenthes out of the water tray and letting the soil remain moist, never too dry or too wet. Have you repotted the plant in fresh soil in the past two years? A yearly repotting aeriates the soil and often activates a growth spurt in many plants.

My thinking is that the Nepenthes root system has grown down far enough to contact the water and is not happy about it. It is fine to overwater for a couple days with a fraction of an inch of standing water in a tray under a large or tall Nepenthes pot, but to have an inch or so of water for weeks or longer with a Nepenthes sitting in it is generally not a good idea.

That being said, I have kept a Nepenthes cutting in a vase of water for over 9 months now just to see what happens. It has been pitchering and finally grew new roots after 3 months. It seems to be fine. The problem seems to occur when the roots are in soil with standing water under a pot.

If the plant were suffering from actual root rot in your case, it would blacken from the top down with the newest leaves up top dying off first.

Christopher

---------- FOLLOW-UP ----------

QUESTION: The plant is not in soil. It is growing on a nice sized piece of pumice rock, as it was a rock or dish garden plant that I purchased from Saracenia Northwest. The rock does not seem to be splitting from the strength of the roots. The only different condition that I can put my finger on is the fact that I accidentally inherited a hermit crab from my son (we thought it was dead, but it wasn't) and I have the crab in an aquarium sitting on a table in close proximity to the nepenthes plant. Is it possible that the crab could have anything to do with the leaves turning yellow? Unlikely, but still a possible contributing factor. I'll try backing off the water for awhile and see if that helps. Thanks for your suggestions.

Answer
Hello Rochelle,

I do not see any reason why a hermit crab in an aquarium near the plant would contribute to yellowing leaves either.

I must have misunderstood you when you indicated a rock garden. When I think of rock gardens I think of a container full of soil with rocks layering the top and plants growing from between the rocks. I do remember Sarracenia Northwest having plants for sale that were implanted in rocks. Perhaps you could ask them if they know of any circumstances that would cause your plant to yellow when grown in pumice in that fashion. My first thought would be overwatering in this case.

Christopher