Contact Us Host an Event Volunteer Join

Support the plant database you love!

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
5 ratings

Sunday - December 20, 2009

From: Bay Point, CA
Region: California
Topic: Non-Natives, Compost and Mulch, Poisonous Plants
Title: Could ammonia harm poisonous, non-native oleander in Bay Point CA
Answered by: Barbara Medford

QUESTION:

Could ammonia harm my Oleander plant? I have been spraying ammonia under it to keep neighborhood cats from using the soil under the plant as a sand box. If so, do you have any suggestions as to what I may use instead? Thank you.

ANSWER:

Ammonia is a compound of one part nitrogen and three parts hydrogen. Household ammonia or "ammonium hydroxide" is combined with water, with usually only 5 to 10 per cent of the resulting product being ammonia. Since both nitrogen and hydrogen are already in the environment, and nitrogen, at least, is beneficial to the soil, it is unlikely that it is going to cause any damage. We wouldn't recommend spraying it directly onto the plant leaves, but it shouldn't harm the dirt or the roots.

If we may take this opportunity, we would like to remind you that the Lady Bird Johnson Wildflower Center is dedicated to the use, care and propagation of plants native not only to North America but to the area in which the plant is being grown. Nerium oleander is native to Africa, Asia and and the Mediterranean. We realize it is widely used in California, but would like to point out one other  characteristic of oleander that may be more important than whether ammonia will harm it. Nerium oleander is one of the most poisonous plants known, with all parts of the plant being toxic. Ingestion of just one leaf can cause heart attack and death. Some of the poisons it contains are cardiotonic glycoside (oldendrine), prussic acid and rutin. Skin contact with the plant can cause severe dermatitis. Burning it will release toxins that can cause intoxication. We would recommend that it be carefully removed, wearing gloves and protective clothing, bagged and disposed of properly, NOT burned nor consigned to the compost pile, where the toxins would continue to be dangerous. 

Now, back to the dirt in your garden and the cats. Rather than spraying ammonia or some other aromatic liquid on the dirt, try a good heavy mulching with shredded bark mulch. Cats don't like scratching in that, its fragrance will alleviate some of the urine smell which is attracting the cats back to the same place, and it will enrich and amend the soil. 

 

More Non-Natives Questions

Identification of non-native Viburnum lantana
July 23, 2007 - Could you tell me what this plant is? I have no idea! Vib Iantana Mohican - this is all the info. I have, other than it can grow in the mid-west.
view the full question and answer

Plants for a nursing home resident from LaQuinta CA
July 26, 2013 - I take care of an elderly woman with dementia. She is in a nursing home and she's always LOVES flowers and plants. Do you have any suggestions for potted outdoor blooming plants for the summer in...
view the full question and answer

Fast-growing non-invasive shrub for privacy fence in Sugar Land TX
December 06, 2011 - I live in South Texas in Sugar Land. I was going to plant oleanders in my backyard along the fence as a privacy hedge, about 20 feet from my house. However, I was told they were a bad choice becaus...
view the full question and answer

Negative and positive effects of invasive dandelions from Rama Ontario
January 12, 2012 - How do Dandelions have a negative impact of being a invasive and a Positive impact of being a invasive species ?
view the full question and answer

Will drought-stricken non-native St. Augustine come back in Cedar Park TX
January 30, 2010 - I recently bought a new house but the grass in the yard looked completely dead (bought house in Nov) even though the neighbor's grass was still green. The previous owner stopped watering the grass (e...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.