Host an Event Volunteer Join Tickets

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
Not Yet Rated

Wednesday - August 06, 2008

From: Wichita Falls, TX
Region: Southwest
Topic: Non-Natives, Pests, Edible Plants
Title: White spots on Hibiscus leaves
Answered by: Barbara Medford

QUESTION:

My hibiscus trees have white spots or splotches on the leaves. What is it and what can I do to get rid of it? Also, the birds are eating my tomatoes faster than i can grow them. I've used the owl & snake tricks which work about a week & then they're back eating again. What do you suggest?

ANSWER:

Again, we have to figure out what plant we are talking about. There are literally hundreds of plants typically referred to as "hibiscus", some annual, some perennial. There are some native hibiscus and many that are non-native, but all belong to the mallow family, so hopefully even if we pick the wrong one to discuss, the same advice will apply. Since you refer to hibiscus "trees" we believe that what you have is a Hibiscus syriacus, native to Asia, and often called Rose of Sharon. There are other mallows called Rose of Sharon, as well, adding to the confusion. A synonym to the current name is Althea syriacus, and lots of people have what they call altheas.

Since the Hibiscus syriacus is non-native to North America, we have no information on it in our Native Plant Database. At the Lady Bird Johnson Wildflower Center, we urge the use of plants native to the area in which they are being used, because they are already adapted to the environmental conditions there and thus will require less fertilizer, water and maintenance. However, we have done some research and will try to answer your questions on the leaf spot. This USDA Forest Service website on Rose of Sharon will give you general information on care for the plant as well as pests and diseases. It is hardy in Zones 5 to 8, and Wichita Falls is in Zone 8, according to the USDA Zone Hardiness Map.

Aphids may cover leaves with sticky honeydew. Over-fertilizing increases aphid infestation. However, we believe what you are asking about is bacterial leaf spot; the only treatment we found for that was to pick off and destroy the infected leaves. Don't leave fallen leaves or blooms on the ground as they may harbor the bacteria.

Now, on to your tomato question. Once more, we are talking non-native plant. Most food plants are either non-native to North America or so intensively hybridized that they bear little resemblance to the original form. Tomato, Solanum lycopersicum, is a member of the Solaneaceae or Nightshade family, closely related to tobacco, chili peppers, potao and eggplant. It is native to Central and South America from Mexico to Argentina. With reference to keeping birds out of them, if we could devise a fool-proof method to keep all the little beasties that love tomatoes, too, off of them we would be zillionaires. See this excellent Texas A&M Horticulture site on Tomato Questions. One which addresses your question is quoted below:

"Tomatoes should be supported. Whether you cage or stake them is personal preference. Regardless of the method, plants with foliage and fruit supported off the ground will produce more than unsupported plants. Caging has several advantages. It involves less work than staking. Once the cage is placed over the plant there is no further manipulation of the plant - - no pruning, no tying. The fruit are simply harvested as they ripen. In many areas, staking and pruning of the plant to a single or multiple stem results in sunburn when the developing fruit is exposed to excessive sunlight. Other advantages of caging over staking include protection of fruit from bird damage by more vigorous foliage cover and less fruit rot. Caged tomato vines produce more fruit of a smaller size, but staked and tied plants produce less fruit which mature earlier yet are larger."

 

More Non-Natives Questions

TIF 419 Bermudagrass vs. Zoysia
September 03, 2008 - I'm currently faced with the decision to sod my yard with TIF 419 or Zoysia. Zoysia is double the price so my knee jerk reaction is to go with Bermuda. Proponents of Zoysia claim it requires less m...
view the full question and answer

Will corn fall victim to allelopathy from hackberry in Clarkridge AR
March 30, 2013 - Will my corn be inhibited by a nearby hackberry and if so would it help to cut it down? I understand that sometimes the soil is full of the chemicals the tree produces.
view the full question and answer

Non-native acacias for Washington State
January 03, 2006 - Hello! I have been unable to find any sources for the seed of Prairie Acacia, Acacia angustissima var hirta. Var angustissima, from tropical America, is in cultivation, but I think it is tender to col...
view the full question and answer

Alternatives to non-native heather (Calluna vulgaris)
April 27, 2007 - I live in Vernon, BC, Canada. I plan to put a heather plant in my garden, but my space is limited. I know that it will grow approx. 2 ft. high and that it likes well drained and acidic soil, but how...
view the full question and answer

Invasive, non-native Cherokee rose in Elgin TX
September 24, 2010 - We have property in Elgin, TX in Bastrop county which has the red sandydirt-loam. The original owners from the 30's, must have liked the Cherokee rose. The problem is that it is planted around our ...
view the full question and answer

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