Your new xeric plants are in, and everything is looking good. What do you need to do to keep it that way? Start by looking at your irrigation controller. It may be programmed to apply water too frequently and/or for too long in order to get the plants started. If you hired a contractor, they may have set the controller to water every day because it’s easier than getting a call about a plant that doesn’t look great.
Many desert-friendly plants and trees evolved to survive on very little precipitation but also to make the most of abundant rainfall when it does happen. They’ll store the water in their roots or grow larger (and produce more seed for dry years) than they would with only adequate water. A xeriscaped yard doesn’t automatically “save” water — it is up to the homeowner to do the actual water saving by adjusting their irrigation controller. My dog would be “happier” if I fed her as much as she wanted, but it’s wasteful (among other things) to do so. Watering your desert-friendly plants too much may cause them to outgrow the space they were designed for, which might mean pruning them more than they need so they don’t grow against the house or over a path or outcompete other plants. Overwatering also creates lush, tender growth that is more attractive to pests and susceptible to frost damage.
A recent study in Arizona found that xeriscaped yards didn’t have reduced water usage because the homeowners applied the same amount of water as they would for a traditional yard with a lawn and non-natives.
Here are steps you can take to make sure you’re watering correctly for your new landscape and keeping your plants healthy:
Reduce the number of emitters if needed: The best way to do this is by cutting off the drip emitter and installing a “goof” plug in the end of the ¼ inch tubing. This is preferable to trying to pull the ¼” coupler out from the larger line, which creates a larger hole that can’t be easily plugged.
Check your irrigation controller: You’ll want to keep the soil moist around the newly installed perennials, shrubs and trees for the first week, and that might mean watering every day if it’s above 90 degrees. After the first week, switch to watering every other day. Then on week three, switch to twice a week. Exceptions would be for cacti, which I would soak once when planting and then water once a week for the first month before tapering off to once or twice a month until established. (Perennials / grasses - 8-10 weeks, Shrubs - 1 year, Trees - 1-3 years.)
Check that drip emitters are working properly, especially if a plant looks wilted: Drip emitters often get clogged after a repair is made in the larger ½” or ¾” poly tubing. If you’re using “flag”-shaped emitters and one is not flowing, you’ll want to grasp the body of the emitter while you turn the top “flag” shape counterclockwise 90 degrees to allow the top to separate from the rest. You should do this while the zone is running so that you can see if any emitters aren’t working and so that the water pressure can clear the clog. Once you’ve twisted off the top, you should have a strong flowing stream of water coming out. Hold your finger over the water stream, forcing it into the drip outlet, which clears the clog.
If you’re using “button”-shaped emitters and one is clogged, you’ll need to cut it off and replace it. Don’t try to pull it off the ¼” tubing, just cut it off and plug in a new one so that the barbed insert has fresh (not stretched out) tubing to fit into.
Keep up with plant growth: As your desert-friendly plants grow larger, you can move the emitters farther away from the base of the plant and add new ones if needed; larger plants require more water. There are several ways to do this. You can poke a new hole in the nearby larger poly tubing, insert a ¼” coupler, run an additional ¼” line to the plant and add an emitter. However, if the main poly line is more than a couple of feet away, install a ¼” “T” in the spaghetti tubing and go from there. It saves time and means fewer holes in the main poly line. Remember, when installing ¼” couplers into the main poly, always poke the hole in the side, not the top; that way if you step on them by accident, they won’t break off. Also, if your plants are on a slope, the emitter should be on the uphill side, so water flowing downhill will cover more of the root zone. Check that water wells are still in place and holding water around the plant.
Inspect your trees: Check the leaves for any insect damage and the underside of leaves for insect infestations. Also make sure the mulch or gravel isn’t covering up any of the tree trunk above the root flare, which traps moisture that can cause decay or rot. Particularly in fruit trees, this can also allow detrimental insects access to the trunk where they could bore into it.
Check the soil around the base of your plants: Often during initial watering, the soil will settle into the planting hole and can expose the root ball, which causes it to dry out quickly. If you observe or suspect this, kneel in front of the plants, move the mulch out of the way and scrape the surrounding soil back around the plant to cover up the root ball. Then replace the mulch and reposition the drip emitter as necessary.
Learn the common or scientific names of your plants: If you don’t have a list, plant tags or a detailed landscape plan, some newer smart phones have a plant identifier built into the camera app (no need to remember the app store password and download another app). The closer you can get to the plant — showing leaves, branch shapes and flowers (if any) — the better the app will work. The phone (as we all know) can be wrong, but it will give you a place to start. Alternatively, send an email with photos to askanexpert@abcwua.org and we can help you identify
Once you know the plant names you can look them up in our xeriscape guide to reacquaint yourself with their water needs and mature sizes. Need help remembering the plant names? Often the plants themselves can tell you. Is it a catmint? Rub the leaves and smell the minty aroma. Turpentine bush? Lemony pine smell, for sure. Maybe it’s the shape of the leaves. Fernbush? Examine the leaves closely and see how they resemble an actual fern from a rainier climate.
As a landscape professional, one question I’ve always dreaded is, “How much should I water this tree?” Honestly, there are so many variables that giving a blanket answer is fanciful. More than likely, a part of the answer is, “More than you are now!” Trees are big plants with lots of leaves, and they can transpire a lot of water. That water is “lost” while the leaves are making sugars via photosynthesis, so trees have a high water demand.
If supply doesn’t keep up with demand, the tree gets stressed. How do you know if your tree needs more water? Learning to recognize signs of water stress can help you stay on top of your trees’ needs. There are some common symptoms and situations that may indicate that they are thirsty.
Water stress can be long-term (chronic) or sudden (acute). Chronic drought stress occurs commonly, as many irrigation systems are set up to be adequate for a newly planted tree. As that tree grows, though, it has more leaves and needs more water. Adding emitters and covering more ground is key to keeping up with the growth. Acute drought stress is less common; it happens when a tree suddenly loses most or all of its water supply, which up to that point was adequate. Finally, most rare of all, water stress can happen from too much water in the soil.
Chronic drought stress occurs when trees haven’t had enough water for some months or years. These trees will have smaller than normal leaves, and those leaves will be sparser in the canopy than normal for that species. They may be off-color, not as vibrantly green as normal. Often, there is dieback in the small, outer branches and twigs.
Annual growth will slow down. Evidence of this can be seen in small diameter branches if you can identify the ring scars that mark the annual growth segments. Ring scars are lines that circle all the way around the twig; they are not bud scars that form at each dormant bud and do not circle the twig. If annual growth segments are shorter last year than the year before, something bad is going on.
The short distance between these ring scars indicates a year of poor growth. This may have been the year it was planted, as that is stressful to trees.
In conifers, we see similar evidence — smaller and fewer needles and shorter growth segments. Often, pine needles will brown out from their tips, maybe just a little or maybe halfway. Conifers keep their leaves for several years, so partially browned needles can really slow down growth potential as the brown part isn’t making sugars. Chronically drought stressed conifers abound in New Mexico forests. They are more susceptible to bark beetle attacks than unstressed trees. Combine beetle-killed trees with very dry trees and wildfire becomes a huge concern.
Acute drought stress might happen when a trench cuts through the root system, such as with a new sewer line is installed. Acutely stressed trees tend to have sudden yellowing and then drying of leaves, maybe just on one side of the tree (the trench side, for example). Acute stress is hard for the tree to recover from.
In either chronic or acute stress situations, leaves may develop brown and dead edges. Termed “marginal browning,” this happens when excess salt in soil water gets deposited at the furthest edge of the leaf, building up to toxic levels. Leaves will often turn pale and then yellow during mid-season, well before fall temperatures normally trigger that.
Yellowing of leaves can be a sign of stress.
How about those few trees getting too much water? In some ways, symptoms can mimic too little water. When the soil is very wet, roots stop functioning due to lack of oxygen. This is of most concern for dryland conifers like juniper and pine. Usually, it is linked to an irrigation system that only has emitters at the base of the tree that run often. The tree doesn’t have the fine root mass near the trunk to take up the water, so the soil remains wet. Fungal diseases are likely to pop up, leading to root death and then tree death. Another symptom of overly wet soils shows up in leaves on deciduous trees like cottonwood — oedema. These are corky scars on the surface of the leaf.
You can reduce tree stress with proper irrigation. Trees seem to do well when irrigation is deep, broad and not too frequent. Watering every day is actually not helpful, especially when right at the base of the tree. Cover the soil with an organic mulch to keep the soil cool and the moisture available to your trees.
Drought stressed sycamore tree, insufficient irrigation and small growing area.
Folks, it’s a hot, dry summer here in central New Mexico. No surprise, you say — we live in a desert. Even for our location, though, it’s hot and dry. This creates a little conundrum for us: keeping our landscape plants growing while using water efficiently.
Tree and surrounding plants being watered by inline drip irrigation.
This applies especially to trees because as large plants with lots of leaves, they need regular adequate water for their size and species to remain happy and continue creating positive benefits for your yard and the city as a whole. Call that a biological law and reality. As temperatures go up, trees’ water demand goes up. That is a good starting point to keep in mind — in times of drought, you should water your trees a little more frequently than you would in a year with abundant rainfall.
Drought stressed tree showing missing leaves and yellowing.
It turns out that over 90% of the water that comes into a tree simply escapes through the leaves as water vapor; the tree keeps very little water inside to grow. This loss of water vapor provides the “suction” that causes more water to enter the root system. It also cools the leaves and keeps them within comfortable working temperatures. Someone once said trees (and plants generally) have figured out a way to guide the natural movement of water from soil to atmosphere, channeling it through their bodies and using it to grow and function, which is one part of the water cycle. Having trees increases moisture in the air, allowing your swamp cooler to perform better.
Trees “drink” very differently than you and I. We have one fairly large mouth into which all the water goes. However much we need, we have one target to hit in order to drink that water. Trees, on the other hand, take water in through their tiny, young roots out in the soil. Water has to get to a lot of soil in order to hit enough of those “mouths” to matter. A lot of tree irrigation eventually fails because there are only a few emitters (and those are often too close to the trunk). Those few emitters cannot put out enough water to satisfy the tree’s demand, nor do they wet enough surface area. (See examples in the photos below.)
Drip emitters located very close to the tree trunk.
What matters to a tree is the volume of water it has to work with. That volume is entirely dictated by the volume of soil that is holding water. And THAT volume is dictated by the surface area that received and absorbed water. The key is to disperse the water throughout the main root zone and do it in a way that allows the water to soak in where applied and not flow to low spots on the ground (which often are gutters. Science has found that most tree roots are located within the top three feet of the soil surface and quite likely even more shallow in landscapes that have not been deeply irrigated for the life of the tree, which is a common condition in Albuquerque.
To properly water your trees, you will need some sort of irrigation system. It could be a bucket you fill from the sink or a state-of-the-art sensor-controlled automated drip system. But somehow you need to put water on the soil surface in a slow, controlled manner so that it can soak into the soil where it is applied. While buckets and hoses work, their simplicity makes them very labor intensive. In-line emitter drip tubing, laid out in a spiral or concentric circles, does a much better job. Once in place, these drip systems can be set to run for two to four hours at a time, about once a week during the hottest part of the year and less often during other seasons. Irrigation improvements qualify for the Water Authority Treebate. See our rebates here.
The ideal target area to irrigate is both theoretical and grounded to the reality of the site. Imagine a donut shaped area centered around the tree trunk. The trunk sits in the center of the donut hole. The body of the donut begins halfway between the trunk and the edge of the branch canopy and extends some distance beyond the edge of the canopy. This theoretical donut represents the ideal critical irrigation zone.
Now enters site reality — maybe there is a house or driveway or sidewalk covering part of the donut (or all three, with the tree located in a tiny unpaved space). We don’t want to encourage root growth at the house foundation, so don’t water within a couple of feet of it. Similarly, where concrete or asphalt covers the soil, root growth is moisture-limited and concentrated immediately under the impervious cover and under any planned or accidental cracks that allow rainwater to slip through. Ideally, we don’t want to water next to the pavement. The more of the donut that is unavailable for watering, the more often you may need to water the limited areas of open soil. Even so, it may simply not be enough soil volume to support the tree, which will then decline. In that case, replace it with a nice xeric shrub!
Recently installed drip tubing around a newly planted Mexican elder and some to-be-planted fennel. Both of those plants are excellent pollinator forage. A 4-inch depth of wood chip mulch will be installed over the top.
Grass lawns in the greater Albuquerque area need supplemental irrigation to survive our high desert climate. Most residential landscapes are watered by pop-up spray heads that include a sprinkler nozzle set into a spray sprinkler body.
We recommend switching out your older sprinkler nozzles and spray sprinkler bodies for more water efficient ones. Take a look below. They are easy to install; check out the pictures to see how simple it is.
These devices provide pressure regulation at each individual spray head. The sprinkler body is the exterior shell that connects to the irrigation system piping and houses the spray nozzle that applies water to your landscape. WaterSense-labeled spray sprinkler bodies with internal pressure regulation can reduce water waste by providing a consistent flow at the sprinkler nozzle. When the sprinkler body maintains pressure near its optimal operating pressure, the connected nozzle is better able to generate the right amount of water spray and coverage for more uniform distribution of water across the landscape.
Installation is simple. First remove the old spray body by twisting it off and then twist on the new spray body.
High Efficiency Rotating Sprinkler Nozzles (multi-stream)
We also encourage you to change your existing spray heads to high efficiency sprinkler nozzles. These nozzles minimize water waste with unique, multi-trajectory rotating streams that deliver water at a steady rate. This slower application rate allows water to gently soak in at rates that soils can absorb. Use these nozzles to replace the sprinkler head on any conventional spray head body or pop-up sprinkler for water savings of up to 30%.
High efficiency sprinkler nozzles are a great solution for upgrading an old and poorly performing sprinkler system. These nozzles create a heavier droplet that is less affected by wind and reduce misting. These nozzles work especially well with pressure regulating bodies. These heads require longer run times. Don't worry it does not use more water, because rotary nozzles deliver water at a slower rate than typical spray nozzles. Therein lies the efficiency: water saturates deep into the root zone rather than running off and evaporating. This can also help reduce the frequency of runs, thereby saving water.
To make the upgrade, carefully pull the riser out of the sprinkler body, it's spring loaded so keep a hold of it while you unscrew the old nozzle and replace it. After you replace the nozzle you may need to turn the system back on and rotate the body slightly to adjust the spray direction. Pull up the existing nozzles in your sprinklers. While holding them, remove the cap from the sprinkler and install the appropriate spray nozzle, as indicated on the plan. If you are using Hunter brand nozzles be sure to also buy this little orange tool to adjust the spray arc. Rainbird nozzles can be adjusted by turning the ridged rings with your fingers.
The jujube is just one of those trees that is extra! Extra fruitful, extra nutritious, extra hardy, extra beautiful. This medium sized tree comes in 400 varieties, many of which are being cultivated and taking root in Albuquerque.
The jujube tree, often called Chinese date, has been cultivated for thousands of years around the world, in Albuquerque for nearly 60 years and in the panhandle of Texas since 1875. Its small abundant fruits are high in fiber, vitamin C, potassium, antioxidants and phenolic compounds and have been used to support nervous system, cardiac and digestive health. Medicinally, it is used as a tonic sweetener in many supportive Chinese herbal remedies.
The fruit can be eaten raw, dried or cooked. Fresh from the tree, when they’re mature and a luscious mahogany brown, they have a crunchy refreshing taste, like a cross between an apple and a date. As they dry, they become sweeter and chewy. Dried, they are delicious in oatmeal, cookies, trail mix or anywhere you would use dried fruit. They make an excellent chai — just boil dried pieces with other ingredients, letting the earthy sweet flavor complement ginger, cinnamon, cardamom, pepper and other traditional chai ingredients. You also can find recipes from Korea, China, Vietnam, India, Italy and many Persian cultures that incorporate the jujube for both sweet and savory dishes.
The fruit is very easy to dry and, in fact, many that you miss harvesting will dry right on the tree. However, we do recommend bringing them inside to dry and cutting the pits out before drying so they are easier to eat and enjoy down the road. If you have a dehydrator, that will speed the process, but they will also dry if you place them on cookie sheets in a spare room, on top of a shed in the sun or even in a car and let our New Mexico dry air work its magic. Jujubes don’t bruise and spoil quickly like other stone fruits, so windfalls and bird-pecked fruits don’t make a mess and are still usable.
We love edible landscapes, so we’re naturally drawn to these fabulous trees. But even if you aren’t looking for food, the jujube is a wonderfully hardy tree for Albuquerque. This tough specimen hails from the buckthorn family, Rhamnaceae, and will grow in USDA hardiness zones 6-11, which is an extraordinary range for any tree! At the moment, Albuquerque is generally zone 7, but as we face climate disruption, landscapers and planners are encouraging planting with an eye to zone 8 or 9 so our shade and habitat trees can withstand increasing heat. Jujubes are deeply rooted and can tolerate drought and saline and alkaline soils. Once established they can survive with small amounts of water, though a strategic watering schedule will increase your yield. Because they’re so drought tolerant, we don’t recommend planting a veggie garden under them or they’ll drink up all the water intended for your zucchini. They do well in full sun or light shade. They can handle sustained days and weeks of 100 degree plus heat, 23 below zero in winter and anything in between. They must have a frost to produce fruit, which isn’t a problem here. Jujubes do sucker quite a bit from their roots, and this rootstock, if allowed to sprout, produces very small, almost inedible fruits that are mostly pit. So, we do suggest being vigilant in cutting down the root sprouts as they appear.
Jujubes make a beautiful addition to any landscape. They have an elegant zig zag branch growth pattern and bright green, shiny oval leaves that can even withstand severe hail. They can be trained to a traditional tree structure or allowed to be a little wild and shrubby. They provide cool shade and habitat for birds, pollinators and other wildlife. Speaking of wildlife, one of us has a friend whose small dog Kipper grabs himself a couple from the ground during ripening season, carrying them happily to his bed to snack on … he’s not wildlife, but that little dog seems to love a jujube even above his biscuit treats. These trees benefit from cross pollination so plant yourself two of these beauties!
Planting trees not only gives you the riches of your tree, but it is also a love letter to the future. As gardeners who are tending land and each other in the midst of climate chaos, we have the opportunity to cultivate healing, repair and hope. With every tree we plant, we can try to leave our small patch of earth a little better than how we found it — cooled with shade, brightened with birdsong and providing nutritious food via a resilient, prized and giving tree. The next time you’re sitting in your garden, allow yourself to dream of a future where someone is harvesting jujubes and appreciating the ancestors who cultivated and left these sweet trees for them.
Learn more about specific types of gardening here:
Author: Corva Rose is an arborist and founder of Tree School, and can be reached through treeschoolNM.com, Jennifer Gardner has been gardening in Albuquerque for 30 years, with an emphasis on residential scale food planting. Have a question about the article? AskAnExpert@abcwua.org
Trees are especially important in arid, urban environments like Albuquerque and Bernalillo County. They provide shade, mitigate urban heat, reduce greenhouse gasses and air pollution, and create wildlife habitat, among many other benefits. All trees, even climate-resilient and drought tolerant species, need to be watered adequately.
It’s worth the investment to keep our mature trees healthy. The mature trees on your property are worth much more than the cost of your treasured appliances and, yes, even more than your roof. Keeping our trees healthy and happy over their lifetime is a minimal investment and a valuable contribution to our community urban forest.
In Albuquerque, we tend to overwater our lawns and underwater our trees. It’s important to understand the basics of how best to water trees. For instance, a tree has two different main types of roots. The feeder roots lie within the first 6-24”of the ground, and the stabilizer roots can be at least 3’ deep You may think your trees’ roots can reach the water table, but you should think again — most of Albuquerque has a water table between 20 and 150 feet’ deep. Your roots are never getting that deep.
Due to the importance of our urban forest and how many people are seeking guidance on how to water their trees, the Bernalillo County Water Conservation Program, and Let’s Plant Albuquerque, partners collaborated to create this How to Build an Efficient Tree Watering System guide and the associated workshops.
The tree irrigation system is inexpensive, flexible, easy to install and long-lasting. It uses drip irrigation attached to your hose bib and can be easily expanded as your tree matures.
When assembling your system there are a few key parts to consider:
Teflon tape is needed to seal the threads at every connection to prevent water coming through.
Take note of the two different types of threads: hose threads and pipe threads. Hose threads are straight and require a washer to seal. Pipe and coupling threads are tapered for water use and will seal with just the application of Teflon thread seal tape.
Timers should be uninstalled and stored with the batteries removed over the winter. Some people like to install fresh batteries every spring to ensure there is no interruption during the growing season.
A pressure regulator is important for all drip systems due to the high pressure in our Albuquerque water lines. The regulator reduces the water pressure coming in from the main water supply. Then, it creates a constant low water pressure through the system, allowing the drip tubing to put out the correct volume of water per minute.
Distribution (lateral line) drip tubing comes in two general sizes, and each has advantages and limitations:
1/2” tubing is more common, and parts are available at big box stores. The run of distribution tubing must be less than 200 feet.
¾” tubing is available from irrigation supply stores. It holds pressure better, and tubing runs can be up to 600 feet.
Inline drip line (emitter line) drip tubing comes in two sizes and includes drip emitters pre-installed in the line every 6”, 12” or 18”.
½” Netafim inline dripline tubing for use around medium and large trees. Use 12” emitter spacing.
¼” Netafim inline dripline tubing for use around small trees. Use 6” emitter spacing.
A flush type of end cap is handy for flushing out the system at season start-up or if a break occurs. It is recommended to remove and store flush caps over the winter.
The watering guidance for the system was developed to not under or over water most trees in Albuquerque. However, irrigation is highly dependent on site conditions such as soil type and microclimate as well as the species of tree. This guidance is meant to be a rule of thumb or starting point, and adjustments should be made based on the local conditions and tree species.
Below are some of the factors that should be considered in generating a watering schedule for your yard:
Soils affect how often and how long you need to water — see the Water Authority’s Irrigation Guide for more details. In general, sandy soils require shorter but more frequent run times while clay soils need longer but less frequent run times.
Always check your plants to evaluate irrigation scheduling. Most plants will look a little bedraggled at 3 p.m. during the summer so check in the morning. Do they seem wilted or pale or have cupped leaves? These can be signs your tree needs more water.
Be aware that symptoms of overwatering and underwatering may look similar.
Occasionally, feel the soil the day after irrigating or use a soil probe such as a screwdriver or coat hanger to evaluate the level of moisture in the soil. If the probe is easy to push in and there is a swampy smell, the soil has too much water. If you can’t get the soil probe more than 4” into the soil, it’s too dry. Ideally, the soil probe can be pushed 12”-18” into the soil 24-48 hours after irrigating.
Consider what size tree you are trying to water. Check out the diagrams above and below to determine how much tube length you will need to meet the required water needs of your tree.
