It’s officially spring in the desert garden. Wildflowers are blooming and many plants are pushing out new growth. Here’s a look at what you can plant, what you should prune, how to adjust your watering schedule for spring, and more.
March is one of the most beautiful months in the desert, and one of the busiest months for desert gardeners. By mid-month, you can put your frost cloth away and prune away cold damage. It’s a joy to see the garden looking good and springing to life!
Note that there are a few tasks that should ideally be performed before mid-March and others that should be done after mid-March. (This has to do with the all-important last frost date.)
March Weather Outlook
March’s daytime temperatures are just about perfect, but the nights can still be cold. The average highs in Tucson and Phoenix are 7 to 8 degrees warmer than February’s, while the average lows are up by only a few degrees. The chance of rain and relative humidity go down while the sun becomes more intense.
Here’s a look at March weather averages in both Tucson and Phoenix.
March Weather Averages (Tucson)
| High temperature | 76°F |
| Low temperature | 47°F |
| Precipitation | .60″ |
| Relative humidity | 34% |
| UV Index | 5.9 |
| Wind | 14 mph |
March Weather Averages (Phoenix)
| High temperature | 79°F |
| Low temperature | 54°F |
| Precipitation | .78″ |
| Relative humidity | 32% |
| UV Index | 5.3 |
| Wind | 7 mph |
If you live elsewhere, enter your city or town in the search bar at TimeandDate.com to find your weather averages. And you can find your average UV index at UVIndex.io.
March Gardening Tasks
Here’s a snapshot of the tasks you can expect to do (or not do) this month.
| ☑️ | Watch for late-season freezes |
| ☑️ | Adjust irrigation schedule |
| ☑️ | Plant “almost anything” |
| ☑️ | Prune cold damage |
| ☑️ | Check irrigation system |
| ☑️ | Divide perennials |
| ☑️ | Pull weeds |
| ☑️ | Continue to harvest citrus |
| ✖️ | Don’t fertilize most plants |
| ✖️ | Don’t plant palms, succulents |
Read on for all the details and exceptions!
What To Do in the Garden in March
March is one of the busiest months in the garden. There are two tasks we’ve all been eagerly waiting for the go-ahead on — pruning and planting.
Prune Cold-Damaged Plants (Finally!)
Once the threat of frost is over, it’s safe to remove any cold damage from your plants. (In Tucson, March 15 is the generally accepted last frost date.)
If you live elsewhere, you can find an accurate last frost date here. Note that most frost dates are averages, which are not at all helpful.
Plants that die back in the winter — perennials, ground covers, vines, and ornamental grasses — benefit from a hard prune. Some, like ornamental grasses, should be cut to nearly ground level to remove old growth while most perennials should be cut by 1/3.
This is also a good time to give some shrubs a hard prune including Texas ranger, bougainvillea, and red bird of paradise. Not all plants rebound from a hard prune, so be sure to check on your particular plant before trying this.
Citrus should not be pruned as a matter of course. For the health of your plant, it should be left growing as a big shrub and not trained into a lollipop tree. Skirting (removing lower branches) leaves the trunk susceptible to sun scald.
But if you have branches that are dead, diseased, damaged, dangerous, or deranged (i.e., the 5 Ds of pruning), March is a good time to remove them.
You can continue to deadhead annuals to encourage flowering.
What You Can Plant
If you’re going to plant in the spring, March is the best month to do it. This gives your plants the most time to acclimate before it gets really hot, which can be surprisingly early. In 4 of the past 6 years, the first 100-degree day occurred in April!
You can plant nearly all trees, shrubs, perennials, vines, and ornamental grasses. If a plant is cold-sensitive, wait until the danger of frost has passed, typically mid-March. You can also move plants and divide perennials now as well.
Mid-March through April is the best time to plant citrus trees. While they can be planted in the fall, newly planted trees are susceptible to frost damage and will need frost protection in the winter.
You’ll find tips for successful spring planting in our article What to Plant in Spring (Month by Month).
March Planting Exceptions
Wait to plant heat-loving palms, cactus, agaves, and other succulents until April or May. They prefer to be planted when soil temperatures are warm.
And hold off on planting annuals. It’s too late to plant cold-season annuals, even though you’ll still find them for sale. (If you can’t resist, realize that they are near the end of their life cycle.) And it’s too early for warm-season annuals. If you’re eager to freshen up your containers, add a few “shoulder season” plants such as dianthus, gerbera daisies, dusty miller, and African daisies.
Adjust Your Water Schedule
It’s time to switch from watering your plants on a winter schedule to watering them on a spring schedule. This means you want to give your plants the same amount of water per watering, but you want to water them more frequently.
Most people water too little too often. Don’t be one of them! Use the University of Arizona’s Recommended Watering Schedule as a simple guide or Landscape Watering by the Numbers flipbook as an in-depth guide.
Not sure how to water your plants in March?
These articles can help:
How to Water Desert Trees: How Often? How Much?
How to Water Desert Shrubs: How Often? How Much?
Check Your Irrigation System
If you have an irrigation system, now is a good time to make sure it’s working properly. Start by checking for obvious leaks and clogged emitters. Tucson Water created this concise 2+ minute video that covers what to look for when checking your irrigation system.
It’s also a good time to make sure the placement of emitters is keeping up with the growth of your plants.
If you live in Tucson, you can arrange a free irrigation efficiency audit by the Tucson Water Zanjeros.
If you’d rather leave it to the professionals, you can have an irrigation technician inspect your system. If you live in Arizona, you can search for irrigation specialists in the Smartscape Professionals Directory.
Watch for Insect Pests
If you grow Texas mountain laurel, look for genista caterpillars, the larval stage of the genista broom moth (Uresiphita reversalis).
They like to dine on new leaves and young seed pods. Learn how to recognize and deal with an infestation here.
You might see aphids this month since they like new spring growth. You can leave them alone since they’re good at attracting beneficial insects (i.e., green lacewings, ladybugs) or you can hose them off. Squirting them with a jet spray does more than simply knock them off, it often breaks their mouthpiece, so they won’t come back and suck on your plants another day.
Watch for Weeds
Depending on how much winter rain you’ve had, you’ll almost certainly see some weeds pop up this month. My first-line strategy for keeping weeds at bay is to pull them when they’re young and the ground is wet.
If you sowed wildflower seeds in the fall or hope some of your plants will reseed, be sure you aren’t pulling any seedlings of plants you want in your yard. 😉
Donate Surplus Citrus
If you still have citrus on your trees, it’s time to harvest. A lot of gardeners with mature trees find they’re overwhelmed with fruit.
Don’t let extra citrus go to waste!
You’ll find a list of places that accept citrus fruit donations in our February monthly guide.
Upcoming Gardening Events in March
There are loads of gardening classes and events throughout March. You’ll find an up-to-date list of gardening-related events in our Tucson Gardening Events Calendar.
It’s time to keep an eye out for the premier Tucson sales that start mid-March and go on through April (i.e., Tohono Chul, Pima County Master Gardeners, the Desert Museum, and more).
And be sure to check ahead to April’s events. Some, like the Pima County Home Garden Tour, require tickets and sell out early.
Don’t live in Tucson? Look for Zoom classes. You can participate in these no matter where you live.
Did you enjoy this article?
Sign up for our weekly newsletter
where you’ll find more great info on creating &
maintaining a beautiful, carefree desert landscape.
Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
