AboutDarlene K. Kittle Expertise I have been a Master Gardener for 19 years and I raise around 300 houseplants a year including tropicals, succulents, and cacti.
Experience She is also studying the Japanese art of bonsai with tropical plants and is President of the Fort Wayne, IN Bonsai Club.
Expert: Darlene K. Kittle Date: 6/17/2008 Subject: Yucca palm with sticky stuff
Question QUESTION: I read an answer you gave a year or so ago about a sticky white substance on a reader's bamboo plant....and you said it indicated insects, but needed more info. I have a sticky substance on my yucca palm. I've had it for about 2 years, but don't know how old it is. I got it at my local Ikea. I recently re-potted it to a large pot, about 18 inches across. The plant stands about 5 feet tall, in the pot and sits in a bright corner next to a south facing window. I water it once every week to two weeks with town water. I've noticed a white powdery appearing substance on the leaves for some time, but thought it was just dust or something (I'm so NOT an indoor plant person). When I went to re-pot it, I touched the white stuff and it is quite sticky. It is most concentrated at the base of the leaves, but is also present as far as half way down the leaf. Can you help me to figure out what it is, and what I can do to fix it?
ANSWER: Kelsie,
It has insects of some type. The sap is called honeydew and it is the
excrement of the insects. It could be from aphids, scale or mealy bugs. You need to take a quart of rubbing alcohol and mix a pint of water with a tablespoon of dish soap then put the mix in a spray bottle and spray the tree thoroughly making sure you get the fronts and backs of all the leaves and the surface of the soil twice a week for three weeks then once a week for 4 more weeks. After that watch it for signs of any more insects and resume spraying if you see anything. The honeydew can be wiped off of surfaces with paper towels dipped in rubbing alcohol.
I suspect that you may have moved it to too large a pot. You should always move a plant into a pot just 2 inches larger than the pot you take it out of. When you water it with all that extra soil it holds too much water so it stays too wet between waterings. Roots need dryer periods to breath between waterings and it isn't getting that
because it stays to wet all the time. In a smaller pot it would have a better chance of using up the water between waterings and have that
breathing spell. It feels like it is sitting in a swamp and drowning, it's roots will begin rotting. Plants like their pots being cozier than you think, in the future never go more than 2 inches larger. For now with this plant be very careful not to water it until it is very dry. Check it with a bamboo skewer inserted into the soil and do not water it until the skewer comes out dry even if this takes 2-4 weeks. In an 18" pot your yucca will outgrow your home in a couple of years. When it does come back and I will tell you how to cut it back and start another one. That should only be done between April 15th and June 30th. My 10 year old yucca is only in a 14 inch pot and I will not move it to a pot any large than that or it will get too big.
Good luck.
Darlene
---------- FOLLOW-UP ----------
QUESTION: Thank you very much. I'll do that tomorrow...the sticky white stuff appeared long before the plant was repotted. I repotted it just the other day. It started looking bad about a week ago. Just another question...would it help this plant to be set on my sunny, south facing front step during the day at all?
Answer Kelsie,
If you set it outside it needs to be in a place it will be shady in the hot afternoon but sunny in the morning and evening so it does not get sunburned. It would like being outdoors under a shady tree 24 hours a day for the summer months until the night temperatures start dropping below 50 degrees. Then it needs to come back inside. Good luck.
