How to pressure wash for plant health
All over the West, droughtravaged gardens are coming back to life. The rain alone is pushing a banner growth year in the wild and in gardens, but many of the longer lived plants may need special attention. The new growth will be a huge lure for all the tiny bugs that seem to show up overnight, suddenly there as if by magic. That is the consequence of years when weather is unusual: The bugs get unusual, too.
There’s an age-old horticultural practice called syringing a plant. It means to pressure wash the trunk, branches and foliage to remove accumulated city grime, dust and dirt. Such fine material can reduce solar exposure to the leaf surface below, weakening the plant’s overall ability to feed itself. Removing the black grime of the inner city is essential during the growing season.
Long ago it was learned that bugs like spider mites tend to afflict dirty or dusty plants first, then infest them thoroughly. Old school gardeners often syringed on a regular basis at critical junctures in the agricultural year to deter this pest, plus aphids, scale and other very tiny species.
The key is to use a jet of water to scour the surfaces and detach bugs. Use a shutoff to adjust the pressure and select a single fine jet nozzle for maximum pressure with minimal water flow. These are much more effective with far less water than the do-it-all gun nozzle. You must adjust the pressure as you go from plant to plant. For example, a stiff cactus can take it full bore, but a tomato plant needs a softer touch.
Syringing is not just spraying the plant. It’s about spraying it from all angles so you scour the undersides of the leaves too. Remember, that’s where the bugs hide and come out later to reinfest the plant. This requires you to observe each plant in detail, which is why horticulturists do this routinely. It’s a great way to force you to really observe the condition of the plant in greater detail.
Timing is Everything
The great caveat about syringing plants is timing. It is true that water applied to the foliage of any plant in the sun will burn the leaf surface just like a magnifying glass if it lingers there. That is why experienced gardeners never water their plants. They just water the soil and syringe the plants.
The time to syringe your plants is early in the morning light before sunrise. Evening is sun-safe too, but lingering moisture this time of day can stimulate foliage disease. Choose a dry warm morning to syringe so moisture on the foliage will dry up quickly before burn is possible. If you can’t get all of a large plant in one morning, try doing it in sections over many days, particularly if you’re a beginner.
It helps to rake under and around any badly infested plants after you syringe them. This removes as many of washed off bugs as possible from the immediate area. Dispose of this gathered material off site to prevent them returning when conditions are more favorable.
Syringing is particularly important to cactus and succulents. They have so many inaccessible parts where rot can begin if dirt or litter builds up there over time. It also brightens their color and increases vigor. Syringing is routine to remove disfiguring white cochineal scale insects that afflict prickly pear cactus. It can help remove scale on fruit trees as well.
Join the old school gardeners this year and give your yard a pressure wash for the summer season. It’s just as effective for plant health as dusting is to your antique furniture. They will thank you with vigorous, healthy growth. So if you’re up early on a beautiful summer dawn, don’t just watch the sun rise, pick up a hose, down your coffee and start pressure washing your way to a naturally clean and healthy garden.
Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com.