Question
QUESTION: My corn plant has recently devoloped a black color on the elbow of its only
shoot. The blackness is moving steadily upwards, at a rate of about 1/2 of an
inch per day.  I would have cut the shoot off already, but it is the only shoot,
and it supports the plant's only 3 leaves, which look fine for now.  ( there is
also new 2 inch sprout growing up from the base of the trunk)

About one month ago, I repotted the corn plant into a giant pot, so I'm
guessing it is suffering from overwatering and stem rot.  I re-repotted it into
a much smaller pot with excellent drainage last night, but I fear it is too late.

My questions:  Can I save this plant by cutting off the shoot?  Can it live with
no leaves?  Is there any other way to stop this menacing blackness?  
Fungicides?  Help!

Thank you! Stephen
ANSWER: Hi Stephen,

Your educated guesses are accurate. The roots have rotted as a result of the excess soil that you added, which retains moisture for too long. Because the roots have already rotted beyond saving, the rest of the plant has no way to get the moisture and nutrients that it needs. That is why the stem is turning black.

If you cut the stem above the black portion and the cross-section of the stem looks healthy, firm, and white, then you may be able to root it in plain water. Likewise, you may be able to cut the small sprout from the cane and also root that in water.

The main cane, however, cannot be saved because the roots are already dead.

Please let me know if any of this is unclear or if you have any additional questions. If you would like to e-mail me some photos, I may be able to provide some additional insights.

If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and nomination for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.

Visit my website at  www.HorticulturalHelp.com
  
Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]



The main cane is

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

QUESTION: Will, thanks for your help!  

When I repotted the plant last night, I examined to roots,and they seemed
not-so-bad.  I cut off a  couple of mushy ones, but the rest were sort of
woody and firm, or very small and bright white.  I put the root ball into dry
potting soil, and let it dry overnight, then watered it a bit this morning.  I'm
keeping the plant out of direct sunlight.   

I will cut off the stem and try to root it, but I feel like the main cane may still
have a chance once it gets settled.  Is this foolish?  

Also, could you tell me exactly how to re-root the healthy portion of the
stem?  Everything I've read on line seems to leave out:  how long, what kind
of container, dark/light?, and how to plant once it roots.

Thanks Will, as you can tell, I am loathe to let this plant die.  Can't we throw a
hail mary and give it a chance?  Thanks again, look forward to your advice.  
Stephen  

Answer
Hi Stephen,

I hear your pain! I have cared for hundreds of corn plants and never seen one recover from the symptoms that you described. The stem has to be cut off or it will die. Stemless, leafless canes do not ever regenerate new growth in my experience, but it may be possible.

Squeeze the lower portion of the cane. If the outer bark feels dry, papery and separated from the inner wood, then there is not even a hail mary hope. Until that happens, I guess there is still a glimmer of hope.

Root the healthy cutting in plain water in a glass or clear plastic container. Change the water weekly. Provide bright indirect light. Within a month you should see some signs of roots developing. After another month or so, the roots should be about an inch long. At that point, the rooted cutting can be transferred to a small 4-inch pot filled with a damp peat-based potting mix. Water it when the top half-inch is dry. Be patient while the roots continue to grow and fill the pot. After that, you will start to see new leaf growth. Move it to a 5 or 6-inch pot only when the 4-inch pot needs water every couple of days.

Please let me know if any of this is unclear or if you have any additional questions.

Thanks for the top rating and nomination already posted.

If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and nomination for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.

Visit my website at  www.HorticulturalHelp.com
  
Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]