Across the Southwest, and perhaps across North America – you can decide if December will be a slow garden month – or if you want to use this month to catch up on things.
December Pruning
It can be too late (or too early) to prune anything.
If you want to though – you can prune rose bushes, or you can wait until January.
For the love of all that is holy do NOT prune any tropical tree this month. It can kill citrus, and it often causes mesquite trees to bleed black sap for the rest of their life.

Depending on species, many pine trees are not too happy about December pruning and they can take forever to heal.
Some fruit trees requite winter pruning (apples, quince) but this is better done in January. If you do prune them, bring some branches indoors and see if they might leaf out for some unique winter holiday decoration.
Weeds
In general in this cooler month weeds are not too rambunctious, and cool temperatures mean slow growth. Slow growth does not mean no growth.
Spring Wildflowers
Did you sow seeds earlier this autumn? They might be sprouting so be sure to water, especially if you don’t get rain.
Bought the seed and didn’t sow it yet? Get it out there! Here’s my post about growing wildflowers.
Rain
Lack of rainfall is something of an issue for many landscape plants, watered or not. If you have lived in the Southwest for a while, you know how dusty it can be. In general plants can tolerate being dusty, but dust blocks sunlight from reaching photosynthetic tissue. Less light is not too bad if there is also no rain to trigger growth, but with irrigation it can be troublesome. It is not critical, but plants generally appreciate a nice rinse. I spray water up over all my plants once a month or so. It is also one way to help clean the yard for the holidays ahead. THINK first! Please don’t do this in the evening if a frost is expected.

Colorful Annuals
Along with washing off your plants, another thing to do to “spruce” up the yard for visitors and for yourself is to plant some seasonal color. Here’s my post on annuals for the cool season.
Autumn Means Leaves Drop
Don’t worry if some desert plants lose their leaves. Many desert landscape plants are what we term “cold deciduous.” In a warm winter they may not lose any leaves at all, but if it gets cold enough, start raking.
There is also a genetic component that decides if leaves will drop. I have three sister mesquite trees all grown from beans from the same mother tree. One is the thorny sister, one is the tall gangly sister, and one goes bald with the least hint of cold.
Vegetables
In the vegetable garden, plant cool season vegetable sets, including onion sets (seedlings). You can also plant cool season herb sets such as cilantro, parsley, dill, fennel, calendula, monarda, yarrow, and nasturtium. While it is too late to start most winter vegetables from seed, you still could start some using sets from a nursery. You could even plant a mini-garden in a large pot. Select one around 8 inches deep for lettuce, 12 to 18 inches deep for bigger crops like broccoli. Here’s my post on growing winter vegetables.

Harvest
December harvesting is fun, especially when you can brag about it to friends and relatives Back East.
Harvest ripe citrus as you need it. A gentle tug will drop fully ripe citrus into your hand. Let un-ripe citrus soak up some more sunshine and get even sweeter. Tree ripened grapefruit is awesomely sweet!
Harvest any pecans left and enjoy them while they are fresh. Get the last of the pomegranate before the birds do. Persimmon can be harvested as well and stored in the fruit drawer of the refrigerator.
Rake Leaves
Back East you need to leave some leaves for the good bugs to sleep in over winter. You need to do that here too – but you don’t need a thin layer all over the place! Rake them into a thick protective layer of mulch under your shrubs or trees.
Or add them to a compost pile. For slow decay you can simply bury leaves in unused flower beds.

Irrigation
If you haven’t yet, switch irrigation controller to winter water schedule.
Fertilize
About the only thing to fertilize in the landscape is a winter rye lawn. Do this once monthly should help it keep looking lush and green.
Vegetables and annual flowers can be fertilized now too, but most other landscape plants should be left drowse through the winter and not encouraged to grow.

Enjoy December
Make Some Time. Don’t forget to go outside and enjoy your yard! Sit in the sun and enjoy. Or use that fire pit I mentioned in an earlier post. Sit out and toast your toes while you enjoy the night sky.
If you like to sky watch, December 2023 features these events: December 4 Mercury at Greatest Elongation December 13 & 14 Geminids Meteor Shower Predicted Peak December 21 Winter Solstice December 22 & 23 Ursids Meteor Shower Predicted Peak December 26 Full Cold Moon
Gifting Season Approaches – Give the Gift of Growing
“A great reference book is key to successful gardening in the region where you live. Arizona, Nevada & New Mexico Month-by-Month Gardening takes the guesswork out of gardening for anyone residing in the Southwest. With this book, you’ll know what to do each month to enjoy a thriving garden all year, from January to December. Chronologically organized, this guide is full of critical gardening when-to and how-to advice, along with illustrated step-by-step instructions.
The book’s author is Jacqueline Soule, a Tucson-based gardening expert. She knows this arid region inside and out, and she’s written several articles and books packed with her gardening advice. Arizona, Nevada & New Mexico Month-by-Month Gardening showcases Soule’s expertise in one easy-to-read guide.”
This book (and others) are available on my book selling site. Buy the book there, and the Horticulture Therapy non-profit Tierra del Sol Institute will get a few pennies – at no extra cost to you.
Or maybe a class? Make some lotion for winter dry skin.
On advice of a business manager – I was told to more actively sell my “products.” I responded, “Start blowing my own horn more?! I’m a gardener and a writer, not a sales agent!” but here goes:
As well as writing about plants, I offer classes online and in person.
Like my Making Herbal Lotion Class.
Then there is the fun and informative Membership site the Gardening With Soule Membership Club. There are many wonderful features to the Club site – in-depth detail on topics (more than mere blog posts) – specific plant profiles – care videos – monthly live Q & A sessions, and much more.
Why do I do all this writing and teaching?
So that you will succeed with your gardening goals, and enjoy gardening here as much as I do!
Thanks for reading,
Jacqueline
Legal
© Article copyright Dr. Jacqueline A. Soule. All rights reserved. You must ask permission to republish an entire blog post or article. Okay to use a short excerpt but you must give proper credit. You must include a link to the this original post on my site. No stealing photos.



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