March is one of the busiest months in desert gardens. It’s officially spring, wildflowers are blooming, and 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, 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 hopefully put your frost cloth away. It’s a joy to see the desert 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. You can find your average UV index at UVIndex.io.
March Gardening Tasks
Compared to last month, there is much more to do in the garden. Here’s a snapshot of the activities you can do this month.
| ✅ | Plant “almost anything” |
| ✅ | Switch to spring water schedule |
| ✅ | Check irrigation system |
| ✅ | Fertilize citrus |
| ✅ | Topdress |
| ✅ | Prune cold damage |
| ✅ | Watch for insect damage |
| ✅ | Pull weeds |
| ✅ | Continue to harvest citrus |
| ❌ | Don’t plant palms, succulents |
Read on for all the details and exceptions!
What To Do in the Garden in March
This month, there are two activities that gardeners have been eagerly waiting to get the green light on — planting new plants and pruning winter damage.
What to Plant in March
You might be surprised to learn that fall is actually the best time to plant most desert landscape plants. This gives them the most time to get established before our intense summer heat begins.
However, spring is the second best time for most plants, and the best time for some. And if you’re going to plant in the spring, March is generally 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 3 of the past 4 years, the first 100-degree day occurred in April!
You can plant nearly all trees, shrubs, perennials, ground covers, vines, and ornamental grasses. If a plant is cold-sensitive, wait until the danger of frost has passed.
Mid-March through April is the best time to plant citrus trees. While they can be planted in the fall, fall-planted trees are susceptible to frost damage and need protection from the cold in the winter.
March is also a good time to move existing plants and divide perennials.
Recommended Reading:
7 Steps for Successful Spring Planting
March Planting Exceptions
Here’s a look at a handful of plants that ideally should be planted later in the spring.
Wait to plant heat-loving palms, cactus, agaves, and other succulents until April or May. They prefer to be planted when soil temperatures are suitably warm. Winter-blooming aloes are an “exception to the exception”. They do most of their growing in the winter and establish best when planted in the fall.
Hold off on planting annuals. It’s too late to plant cold-season annuals, even though you’ll still find them for sale. They are near the end of their life cycle and won’t last much longer. And, depending on where you live, it’s probably too early for warm-season annuals. Ideally, they should be planted once the nighttime lows are above 55°F.
If you’re eager to freshen up your containers, add a few “shoulder season” plants such as dianthus, gerbera daisies, dusty miller, and osteospermum.
Adjust Your Water Schedule
Sometime this month, you should switch from a winter to a spring watering schedule. This means watering more frequently. Use the chart below as a simple guide, or see the Landscape Watering by the Numbers flipbook for an in-depth guide.
Not sure how to water your plants in March?
These articles can help:
7 Tips for Watering Landscape Cactus (& Other Succulents)
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 system.
It’s also a good time to make sure the placement of emitters has kept up with the growth of your plants.
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. If you live in Tucson, you can arrange a free irrigation efficiency audit by the Tucson Water Zanjeros.
What to Fertilize
March is a good time to fertilize pomegranates, fig trees, and citrus.
Citrus should be fertilized three times per year and should have received their first feeding sometime in January or February. The window for their second feeding is between March and April.
There’s more to fertilizing citrus than haphazardly sprinkling fertilizer around a tree. Learn how to fertilize citrus for best results in our article How & When to Fertilize Citrus Trees.
Few desert landscape plants need fertilizer, but most appreciate a topdressing of compost or organic mulch. You topdress your plants any time this spring.
Learn which desert landscape plants need fertilizer — and which do not — in our article Should You Fertilize Desert Landscape Plants?.
Prune Cold-Damaged Plants (Finally!)
In Tucson, March 15 is the widely accepted last frost date. If you live elsewhere, you can find an accurate last frost date here.
Once the threat of frost is over, it’s safe to remove any cold damage from your plants. Finally! I know we’re all tired of looking at our sad-looking plants.
Plants that die back in the winter — perennials, ground covers, vines, and ornamental grasses — benefit from being cut back sometime this month.
How far to cut back depends on the plant. Some, like ornamental grasses, Texas ranger, bougainvillea, and red bird of paradise can be pruned severely to remove old growth, while other plants should only be lightly pruned or trimmed back by one third.
You’ll find the pruning best practices for over 200 landscape plants in our Desert Plant Library.
Citrus should not be pruned as a matter of course. They should be left to grow as a large shrub rather than 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 learn more about pruning citrus here.
Watch for Insect Pests
You might see aphids this month since they like new spring growth. You can leave them alone since they’re good for 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.
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.
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.
You can keep the number of weeds down dramatically by following this simple rule. Pull your weeds before they seed. When a weed is left to go to seed, it can produce hundreds of seeds — which become next season’s weeds.
If you sowed wildflower seeds in the fall or hope that some of your plants will reseed, be sure you aren’t pulling any seedlings of desirable plants. 😉
You’ll find information on how to identify common weed and wildflower seedlings here.
Stinknet
Stinknet is a weed that’s in a category of its own. It’s bad news even in its native South African habitat. But here it’s an alarmingly aggressive, invasive plant that threatens desert biodiversity, contributes to wildfires, and emits toxic gases when burned.
Every gardener should know how to ID it, what to do if you find any, and how to get rid of it safely. To learn more, watch this video or visit Stinknet.org.
Continue to Harvest Citrus
Continue to harvest any citrus that is still on your trees. Many 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 the February monthly guide.
Upcoming Gardening Events in March
The number of gardening classes and events really picks up in March! You’ll find an up-to-date list of gardening-related events in the Tucson Gardening Events Calendar.
It’s time to keep an eye out for the much-anticipated plant sales that start mid-March and run through April — Tohono Chul, Pima County Master Gardeners, 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 online classes. You can participate in these no matter where you live.
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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 over 15 years.
