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Tuesday - October 27, 2009

From: Monroe, LA
Region: Southeast
Topic: Non-Natives
Title: Care for non-native Mexican ruellia in Monroe LA
Answered by: Barbara Medford

QUESTION:

Dwarf Mexican Petunia I have found information that late in the season, when growth becomes leggy, cut back plants by as much as a half to force a new spurt of growth. Watch for tobacco bud worms, aphids, snails, and slugs. What is the most effective plan for controlling the above problems? I have grow beds and all my potted plants both in the hoophouses and out in the open are on black ground cover secured with six inch staples.

ANSWER:

You are really dedicated to those ruellia; we believe we just answered a question from you about holes in the leaves of your ruellia. They are, as we mentioned to you in our last answer, still not native to North America, and therefore out of our range of expertise.

In fact, the holes in the leaves that you asked about last time may very well have been caused by slugs or snails, the bane of any plant that is in moist soil and shading the ground for the beasties to hide. From The Garden Helper, we found this information on Controlling Snails and Slugs in Your Garden.

Apparently the tobacco budworm is quite a pest of geraniums and petunias, and this University of Florida Entomology Dept. website  on Tobacco Webworm has some suggestions, but no guarantees, on control. 

Aphids are really pretty easy to control-a good squirt of water or, if you are really serious, a good squirt of soapy water, will wash them off and they can't get back onto the plant. This University of California Integrated Pest Management website discusses the control of aphids in more detail.

As for trimming your plants back in the Fall; this is always a good idea with perennials. We like to leave about 6 inches of the stalk so we will know where they will begin to emerge in the Spring and not accidentally mistake them for weeds and yank them out. 

 

 

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