Plants don’t thrive in the dark. I don’t either. For a while I lived in Michigan and felt like a plant. I didn’t mind the cold and snow, but I really couldn’t stand the lack of light in the dark days of winter. Some time later they coined the term “Seasonal Stress Disorder.” Too late for me, I had moved to Texas.
Seasonal Stress Disorder is a normal human response to the problem of less day light. Less day light as the seasons change has been a problem for our green plant friends for millions and millions of years. Plants need sunlight to feed themselves, so less hours of light can mean starvation time. Yes – even in the sunny Southwest.
Short Days are Slow-Down Days
As the days shorten, light lessens and plants respond by slowing down. Their genes know what’s coming. Many species shut down non-essential systems. Non-essentials include leaves, stems, buds, and almost all growth processes. In many species, roots remain active all winter, which is why we garden writers tell you to plant in fall.
The seasonal shut down means that leaves will fall off trees. In some cases they “change color” first. If you want some of that autumn color in your yard – some choices for autumn color from low-water landscape plants are on my other blog – here.
Other season changes experienced by most of your landscape plants include less growth. This means less water. You should already be on you fall irrigation cycle, and switch to the winter cycle November 15 (or today)! Be sure you are not watering your landscape succulents at all right now. Water during dormancy can cause rot.
Exceptions – Of Course
There are exceptions to every rule, and plants are no different. Some plants start growing in the shorter days of winter. Native plants that grow in winter are the ones with genetic ancestors from northern climates. Surprisingly, this includes brittlebush (Encelia farinosa) and desert marigold (Baileya multiradiata), both related to sunflowers.
Meanwhile – from a garden standpoint – there are many “Back East” flowers that prefer our cool winters! These we can grow as winter annuals. Flowers like pansy, calendula, violet, snapdragon, alyssum, nigella, and more. Read more about annuals for winter color – here.
Less Light Indoors Too
Houseplants can stress due to reduced light. Most houseplants are originally from equatorial rainforests, where the day length never changes. Less light and they can drop leaves. You can help by using the bluer light bulbs. Or you can use grow lights. Pay attention – you often need to water less! Also – don’t fertilize for a few months, like until St. Patrick’s Day.
Lucky for all of us, winter only lasts about four months in southern Arizona. By mid-February, most plants will be starting to grow again. The exception? Plants with ancestors from the tropics, like mesquite. They will wait until after our last frost date to grow – around April first. Meanwhile, for us humans, winter is a great time to get out and enjoy the sunlight without the scorching.
If you live in Southeastern Arizona, please come to one of my free lectures that I mention on my Facebook page. After each event I will be signing copies of my books, including “Month by Month Gardening for Arizona, Nevada, and New Mexico” (Cool Springs Press). This link is to Amazon and if you buy the book there I will get a few pennies.
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