I was checking in with one of my favorite clients and she said, “First, come look at my lime tree, I think it might have some of those newish citrus pests.”

She is a very observant natural gardener with a productive Tahitian lime tree in her hot, windy Hawaii Kai garden.

Sure enough, right off the bat I could see that her lime tree was being attacked by several pests.

Just like when we get a little stressed, we can get a little sick. If we don’t take care, seek proper treatment and rest, we can get sicker.

Same with plants, a little stress and one pest hones in. The pest population builds up, feeding on the stressed plant tissues and more pests come and join the party.

I could see citrus psyllids, little black, sap-sucking bugs, along with citrus black flies. They feed on the new leaves and deform them, which makes a prime place for more tiny insects to grow and feed. I saw silvery slime trails, curved leaves and lots of these new pests that attacks citrus trees, as well as mock orange hedges.

I rubbed off and smashed the pests with my hands after I showed her what they look like.

My prescription?

>> Wash and rinse the whole tree vigorously with a strong blast of the garden hose.

>> Spray the leaves, especially the undersides with a soapy water solution. You can use dish soap such as Palmolive (1 tablespoon per gallon of water). Leave the soapy solution there to smother the pests for about an hour.

>> Rub off any sooty mold or dead insects with a soft rag.

>> Pour some soapy solution over the root zone. Often if there are pests on the leaves, they are attacking the roots too.

>> Check for ants and pour soapy solution on them. Ants transport the pests.

>> Watch for slugs and snails and eliminate them.

>> Cleanly trim off dead branches.

>> Get rid of lawn grass at the base of the tree, at least 1 foot in diameter. Replace the grass with leafy mulch and top-dress with cinder.

>> Keep monitoring for pests.

>> At least once a week, thoroughly wash down the leaves of the tree.

Benefits of rain, rinsing

You know how a good rain seems to refresh every plant and clean the air? Rain is such a benefit to plants because it washes off the leaves, rinses down nutrients/pollutants out of the sky and makes them into a form that plants can use.

Rain and wind also knock off pests, especially incipient ones before they really attack your plants or build up in numbers.

If plant leaves are dusty or have sooty mold (that black yucky-looking stuff often seen on gardenias, citrus and mock orange), they are not getting the full photosynthetic benefit of the sun. The chlorophyll in the leaves is somewhat blocked by dust, dirt and mold.

Rinsing and cleaning the leaves and plants is what nature does in a nice windy, rainy summer storm.

While rain is much better than watering, we can somewhat replicate it in our gardens.

I like to rinse down my plants, especially on a hot day.

Visualizing the goal of clean, bright shiny leaves, free of pests, will help you direct your hose in the right leafy places.

Heidi Bornhorst is a sustainable landscape consultant specializing in native, xeric and edible gardens. Reach her at heidibornhorst@gmail.com.