Explore Plants

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
    
 

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Friday - June 10, 2011

From: White Oak, TX
Region: Southwest
Topic: Non-Natives
Title: Problems with non-native althea in White Oak TX
Answered by: Barbara Medford

QUESTION:

I have an althea bush that is 2 years old. I have never had a problem with it before but this year only half of it has leaved out and is blooming. The other half has some very small leaves and very small blooms but will not bloom or continue to leaf out. I tried putting some fertilizer on it to help the problem and discovered that ants had made a home in that side of the bush actually in the branches and the roots. Is there any way that I can save it?

ANSWER:

Hibiscus syriacus, Rose of Sharon, formerly referred to as Althaea syriacus, is native to India and China and therefore falls out of our realm of expertise. The Lady Bird Johnson Wildflower Center is committed to the growth, protection and propagation of plants native not only to North America but to the areas in which those plants grow natively. We realize you probably bought the plant locally, but the fact that a plant is sold locally does not mean that is native there or even, in some cases, will survive at all.

There are a number of problems that this plant can have, including leaf spots, cankers, rust, aphids and spider mites. Putting fertilizer on an already stressed plant is never a good idea-the fertilizer pushes the plant to put on new growth when it is just struggling to survive. Also, the fertilizer will encourage  production of leaves, at the expense of blooms. Using a high-nitrogen fertilizer, such as a lawn fertilizer, will only discourage blooms.

We don't believe the ants are your primary problem. Please read this previous Mr. Smarty Plants question involving ants, which turned out to be an aphid problem. An excerpt from that answer:

Ants are farmers and very fond of aphids, but not to eat. They will protect or fiercely defend aphids so they can harvest the "honeydew," exuded by the aphids. That honeydew is a major food source for the ants. On outdoor (and sometimes indoor) plants, ants protect and care for honeydew-producing insects such as aphids, soft scales, whiteflies, and mealybugs, increasing damage from these pests.

What to do about it? Since your plant is non-native to North America we have no information on it in our Native Plant Database. If you eliminate the aphids, the ants will move on to somewhere else they can practice their honeydew farming.   We recommend a good hard spray of water onto the affected plants, which knocks aphids and their eggs off and they can't get back up. The next thing you can do is try to keep the aphids from wintering over in your garden. See this aricle on Controlling Aphids in Your Garden.

If you don't find indications of aphids on your plant, search on the Internet for the other problems that Hibiscus syriacus is known to have and are listed above.

 

 
 

More Non-Natives Questions

Fruit trees for Buckeye AZ
May 16, 2010 - I am moving to Buckeye Az from Utah and would like to know what type of fruit trees I can grow. Thanks!
view the full question and answer

Information about ice plant (Carpobrotus edulis)
May 06, 2008 - I recently planted some Carpobrotus edulis, Ice plant, and wanted to know if I can mulch or put stones around the entire garden and plants. They are a ground cover plant.
view the full question and answer

Non-native crepe myrtles in Coleman, TX
March 06, 2009 - We want to plant 2 white crepe myrtle trees on our family cemetery plot in Coleman TX. Once they get established, they will be pretty much on their own. Wind and sun are abundant. Rain is scarce. ...
view the full question and answer

Information about non-native Night Blooming Jasmine (Cestrum nocturnum)
June 23, 2009 - Hello, I have been trying to identify a shrub that has been in my backyard for many years, and I happened to come across your website. I was able to identify the plant as Night-Blooming Jasmine, but t...
view the full question and answer

Problems with non-native hollyhock in Austin
April 03, 2010 - Our hollyhocks develop small yellow spots on the leaves; these eventually spread into little swellings on the underside; I think of them as lesions. They spread and the leaf turns brown and shrivels ...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.