Tips to get rid of scale bugs for good on indoor trees

I have some indoor trees: an avocado, grapefruit and two tangerine trees, which were doing fine until suddenly weird growths started appearing on the leaves and stems.

If I bend the leaf just right, they peel off and squish like an aphid or some other insect. They seem to be leaving some sugar residue on the leaves. I’m not sure what they are or what I can do to get rid of them. Appreciate any advice.

— Bret

It’s difficult to say without looking at a sample, but it sounds as if it could be scale.

Scale can be a tough insect to control because they are pretty well-protected by a waxy shell under which the insect hides. We usually go after them with a two-pronged approach.

First, use a soil-applied systemic insecticide. This comes in different forms, mostly granules, though there are some spikes you can use.

Second, you want to spray the plant with a contact houseplant insecticide. A houseplant spray containing a synthetic pyrethroid insecticide such as Permethrin or Resmethrin works well, but you also could use insecticidal soap or Season Long Spray Oil.

It’s important with the last two that you get complete coverage of the plant when you spray, including the undersides of the leaves. The soap and oil really have no persistence and have to come into contact with the insect while wet to control them. Though you have to be very thorough with your coverage, folks like to use them because they are safe products with no poison in them.

The last ingredient to good control of scale is persistence. You will need to apply the systemic insecticide every three to six weeks, depending on the product. You should spray the contact insecticide about once a week. Keep this schedule up for one to three months. Basically, you’re wearing down the insects.

I have a terra cotta strawberry pot with some strawberries in it. I’m afraid to leave it out all winter. Can I keep it in my shed instead?

— Kelly

Actually, strawberries are pretty darn hardy, and though it’s possible that we can get cold enough over the winter to kill or damage them, most winters they come through in pretty good shape.

The issue that may be of bigger concern is how well your pot will survive the winter. You’ll have to maintain some moisture in the soil the strawberries are growing in and sometimes the expansion and contraction of the potting soil from the freezing and thawing can cause the pot to crack or crumble.

Strawberries are evergreens (there should be some green leaves among the dead ones), so they will need some light. Without it, they will suffer and may not survive until next year.

The best suggestion I have is to put the pot in a shaded, protected spot. This will slow down moisture loss in the soil and should keep the soil frozen, which will actually help preserve the pot. It’s that freeze — thaw — freeze — thaw cycle that really starts to eat at them.

You’re going to have to accept some risk of losing the pot eventually, but this should increase the chances of it coming through OK. Also, some folks just go ahead and treat their strawberries as annuals. Once most of the leaves die back, they empty the pot, throw out the plant and store the pot in a shed for next year.


I have flowering inside hibiscus that hasn’t bloomed in a while. It has lots of new growth but is getting real leggy. What can I do to make it bloom?

— Dottie

Tropical hibiscus usually don’t bloom well inside the house because of a lack of light. It’s surprising how much darker even a bright room indoors is than outside.

If there is a brighter spot for it in the house, move it there. Otherwise, do the best you can to get it through the winter, then move the plant outdoors once it warms up in the spring to a spot where it will get some shade in the afternoon.

Cut it back a bit to reduce the legginess, which will stimulate lots of new growth. They bloom on new growth, and that will mean more flowers on the plant this summer.

Dennis Hill is the nursery manager at Bookcliff Gardens, Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or email .(JavaScript must be enabled to view this email address).


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