Do Holiday Lights Harm Plants?

Light is miraculous.    Life on Earth as we know it would not be possible without light.    This season many different religions celebrate both spiritual and physical light and do so with – light.    Lots of light.    Strings and strands of shining light.  Flashing light. Twinkling light. The more the merrier!

Light With Care

But while festooning your home and landscape with light is a wonderful way to celebrate the season, some caution is needed – especially here in the Southwest.

Cactus Need Dark

First, a number of our Southwestern plants can be harmed by holiday lights, especially our iconic cacti and palm trees.    Dr. Mark Dimmitt, former Director of Natural History at the Arizona-Sonora Desert Museum in Tucson, Arizona explains why this is so.

“All cacti, including the stately saguaro, have a very special system for photosynthesis in the arid desert which saves them as much water as possible.”

Their type of photosynthesis is termed Crassulacean Acid Metabolism, called CAM for short. CAM means that they start photosynthesis in the light of day and then put it on hold. They literally hold their breath and wait for it to be dark. Then, in the dark and relatively cool air of nighttime, they open their pores and breathe. This means they can take in the air they need to finish the photosynthesis process – and make the food they need for life.

Opening their pores to breathe means that the cacti will lose their precious water to the dry Southwest air. It’s their solution to living in a place where water is scarce.

Dr. Dimmitt says, “Holiday lights placed on cacti, and left lit all night could slowly starve the cacti to death.” He went on to explain, “Yes they store some of the sugar they need for life, but they can not store enough to go a month without breathing.”

Tropical Plants May Be Harmed

Palms and other plants of tropical origins are also threatened by holiday lights Dimmitt notes.    Palm trunks are ok to light, but avoid lights in the crown, the top leafy part.    Palms are encouraged by the extra light to send out new leaves too early in the year.      Dimmitt says, “Frosts can kill any new foliage that appears too early.    If the palm is already weakened, because of drought or other stress, this can lead to it’s demise.”

Dimmitt notes that a number of other frost sensitive tropical sub-tropical and desert plants, such as yellow bells, bird of paradise, Texas olive, and desert willow can be likewise affected by holiday lights.

Balance Is Key

But it doesn’t have to be all or nothing with holiday lights. The solution is to simply have a timer on your lights. I found one for under 15 dollars at a local hardware store. I set it to turn off at 11 at night. Most folks are in bed by then anyway.

As a side note to this, our game camera caught an endearing image of a very startled coyote when the holiday lights went off. It’s up on my TikTok channel.

One Final Issue

You do need to take those strands of lights off your plants.  Yes it can be a pain to wrap and unwrap and rewrap your trees, but if the wires stay on the trees it can damage their growth.  Ultimately the tree may grow tissue over the wires.  These wires embedded in the trunk cause the tree to grow weakly wooded and liable to fall in a storm.  

Dark Sky Community

I posted earlier just a little about the issue of light pollution in the Southwest, an area renowned for telescopes and viewing the night sky. A sky that needs to be a dark sky. Lighting your yard at night can be detrimental in so many ways.

There is no “bogeyman” that will get you if you turn your lights off at night. Also, some evidence suggests that so called “security lights” end up helping nefarious people identify which homes think they have important “stuff.” The light also helps them see their way. I shall have to do a post about security plantings and securing your yard.

Do Celebrate With Lights

Do have holiday lights if you wish! You should feel free to celebrate the season with holiday lights.    As long as you turn them off each night by midnight, and take them down at the end of the season. Two simple rules of thumb. You and your plants can have a happy holiday season, this year and for years to come.

We leave our lights up and lit each evening through Epiphany to help our Orthodox neighbors celebrate. In their tradition, the Twelve Days of Christmas mark the days between Christmas day and the day that the Wise Men arrived with their gifts, Epiphany.

Gifts from the Garden

Want to make some simple and simply wonderful gifts from your garden for the holidays? You can, of course, head over to Savor the Southwest for gifts from your kitchen. 12 Gifts to Make – for the 12 Days of Christmas.

But you could also head over to my Gardening With Soule classes site and learn to make some Luscious Lotion. It is easy as can be! Just a few ingredients from most supermarkets, one from the hardware store – and the tools you already have, a spoon, a kitchen blender, a stove, and a pot.

Legal Notes

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