Ask the Gardner

Bring plants - not bugs - in for winter

CORRESPONDENTNovember 13, 2010 

Q: I know this is rather late in the season to ask, but I have several potted plants on my deck and porch that I'd like to "over-winter" in the basement or shed. My husband is concerned that we'll bring bugs inside - we have had ants in some other pots. Is there anything we can water into the soil to get rid of unwanted bugs before taking these plants in? - Janet Giannattasio, Raleigh

A: Well, luckily for your plants, the month of October was one big Indian Summer, so extending their stay outdoors for the ghouls and goblins of Halloween to admire probably didn't cause them any harm. As for bringing in bugs with your plants, a good way to prevent this is to water the soil in the pots with a liquid mix that contains a contact bug killer such as pyrethrin. However, water-soluble pyrethrin is not a common product in most garden shops, so you might want to try the "Titanic tactic" to drown any insects hiding in the dirt by simply sinking the pots in a container of lukewarm water for about 20 minutes.

These soil treatments will take care of most bugs that think they can sneak indoors underground, but some insects come in as eggs and hatch in the warm environment of a winter home. Many of these eggs will be attached to leaves (usually on the undersides), so wiping the foliage with a damp cloth will eliminate much of this problem.

I've known more than a few folks who have resorted to clearing bugs off their houseplants with a can of common bug spray - don't do it. Unless the label says it can be used safely on plants, insect killer could also be plant killer. Many insect sprays for home use are oil-based and could suffocate plant leaves.

Q: I recently bought three Japanese anemone plants before knowing anything about them. I am now afraid that I made a bad decision, since learning that they can become invasive. Will they thrive in a container? - M. Sherman,

A: Well, in comparison to, say, kudzu or bamboograss (Microstegium vimineum), I wouldn't call Japanese anemones invasive. They tend to take their time becoming established, but once Japanese anemones do - and find the soil, which should be highly organic in composition yet near neutral in pH, to their liking - they will begin to spread by clumps.

If unchecked, it could result in a whole lot of Japanese anemones in one bed, but this can be easily countered in a time-honored Southern gardening kind of way - give excess plants to other gardeners. If this is done every two to three years, these beauties, which bloom from late summer into the fall, shouldn't take over your garden.

If you grow Japanese anemones in pots and remember to water them in the heat of the summer, a large container could be an option. After becoming established, these plants are somewhat drought-tolerant so I certainly wouldn't hesitate to plant them in the garden. They have been Southern garden favorites since the mid-1800s, and if they were truly invasive beasts, we would be hurling invectives at them the same way we do kudzu and bamboograss.

askthegardener@newsobserver.com or southeastgardening.com

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