Nothing adds the same quality and value to a landscape as a healthy mature tree. The benefits include cooler outdoor spaces, cooler homes, aesthetic appeal, carbon capture, stormwater mitigation and more. There are some key things to think about when it comes to keeping your big old tree happy.
What are the key parts of the tree and what do they do? All the parts are important, many are redundant, and how they play together really matters. The redundant parts are leaves, small branches and small roots underground. While critical for tree health, the tree can lose some of any of these without suffering fatal damage; the tree will, with time and to the best of its ability, replace those lost parts with new growth.
The fine roots explore for water and minerals in the soil, hopefully with the help of symbiotic soil fungi. Only the youngest, smallest roots (those that haven’t even grown bark yet) take in water, like tiny sponges. These roots grow when and where soil moisture is available and die off when the soil gets too dry. Trees may have several flushes of absorbing roots growing and dying back over a season. Once in the roots, water moves up successively larger roots as it travels toward the stem.
There is one part of the tree that is not redundant. This is the root crown, or root flare, where the ropy wood of the root system changes into the blocky wood of the stem. The happiest, healthiest trees have a strong root flare visible above the soil line. These root shoulders act like buttress supports for the huge load of wood and foliage being acted on by gravity and wind.
As water moves up the trunk, it travels in sapwood (or xylem) — living wood just underneath the bark layers. Outside the sapwood is a thin ring called the cambium, cells that make new cells that make new cells … for as long as the tree lives. Outside that layer is the inner bark (or phloem), a green spongy layer with many functions, including moving sugars and other metabolites from the leaves to wherever they need to go. These three layers — xylem, cambium and phloem — constitute the “living rind” of the tree and are protected by the dead but intact outer bark layers. The central wood, or heartwood, is dead but intact as well.
Leaves out at the end of the small branches are busy converting sunlight energy into stored chemical energy in the form of sugars. These are then used as fuel and as building blocks for the tree to power its ongoing life functions and make the complex chemicals needed to do so.
What harms a tree? Things that harm the root system (soil compaction, drought, heat, chemicals), things that damage the root flare (stem girdling roots, mowers, construction), things that damage the living rind (wire girdling, kids with hatchets, vehicles) and things that damage leaves (over pruning, certain herbicides, heat). There are feedback loops, especially between the roots and the leaves. Root damage that reduces water uptake leads to leaves making less sugar which means less resource to grow new roots. Herbicide damage that deforms leaves leads to less sugar feeding root function as well as less pull on the water, both leading to less water and nutrient uptake going back to the leaves.
So, here’s what you do: Avoid those harmful things!
Protect roots by covering the soil with 3 or 4 inches of arborists’ wood chips. This cools soil, reduces soil water loss, cools air above, breaks down and feeds minerals into the soil, and promotes growth of beneficial soil fungi. Avoid cutting roots when possible; when necessary, cut as few as possible and cut as far from the trunk as possible. Don’t compact soil by dumping gravel all over it or parking on it. Don’t apply herbicides to the root zone, which is larger than the canopy above.
Protect the leaves by avoiding over pruning. Most mature trees don’t need regular pruning, and, in fact, that should be avoided. Pruning takes away energy sources (leaves) and creates energy sinks (wounds that must be dealt with). Excessive pruning can send a tree into a starvation spiral. Prune for specific goals. Avoid herbicides like those found in weed-n-feed fertilizers.
Protect the living rind by taking away Junior’s hatchet. More seriously, don’t tie wires or ropes around the trunk and branches unless you check them every year to make sure they aren’t girdling the tree. Lastly, don’t run into them with your car!
A tree-protection cage which has become a tree strangling cage. Severely stunted growth on an ash tree; imazapyr herbicide damage is likely cause.Construction damage, while often unavoidable, will lead to health decline in mature trees.
Author: Joran Viers is an arborist at Legacy Tree Company. Contact him at joranviers@legacytreecompany.com Have a question about the article? AskAnExpert@abcwua.org
The Water Authority offers several rebates for irrigation efficiency equipment that might help you reduce water use your yard. You also can contact a Water Authority irrigation specialist at AskAnExpert@abcwua.org for a consultation or efficient irrigation advice. Find more information about the rebates here.
WaterSense Smart Irrigation Controller: A WaterSense-labeled controller reduces watering times or the number of days when the system goes on so that less water is delivered to plants during the cooler months or when it has rained recently. Receive a rebate of 25% of purchase and professional installation costs, up to $100. Choose from a list of pre-qualified controllers here.
Smart Water Application Technology Flow Sensor: Meant to be used in conjunction with a smart controller, irrigation flow sensors measure the speed at which water is flowing through an irrigation system and then send that information to the smart controller. This helps detect problems and conserve water. For example, if water is flowing at an unusually high rate (such as from a line break or broken sprinkler), a flow sensor works in conjunction with the controller to take corrective action. Receive a rebate of 25% of purchase and professional installation costs, up to $100.
Smart Water Application Technology Pressure Regulators: Pressure regulation devices increase the efficiency and performance of your sprinkler and drip system by reducing the water pressure to a set, optimal rate. This is important to improve water distribution uniformity and avoid underwatering or overwatering. Receive a rebate of 25% of purchase and professional installation costs, up to $100.
WaterSense Pressure Regulating Spray Sprinkler Bodies:These devices provide pressure regulation at each individual spray head and can reduce water waste by providing a consistent flow at the sprinkler nozzle. Get $4 off each sprinkler body you purchase (no limit).
High Efficiency Rotating Sprinkler Nozzles (multi-stream):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 system. In most cases, you just remove the old, water wasting spray nozzle and replace it with the new head. You don’t even have to take the main sprinkler body out of the ground. For more information on these nozzles check out this post. Get $2 off each nozzle you purchase (no limit).
Regardless of how you water, you will want to create a berm, or raised “dam,” on the downside when planting on a slope. This berm captures any rainfall coming down the slope, detaining it long enough to soak in, and also holds water that comes from irrigation or hand-watering. By cutting away part of the slope on the upside of the plant, there’s additional room to capture and retain more water. Our diagram (put the word “above” or “below” here, as is appropriate) shows these methods using a berm with wood mulch. Our preference is to create the berm out of soil and apply shredded wood mulch inside the well created by the berm because shredded wood mulch will help moisture stay longer in the soil.
If you are watering plants by hand, turn down the pressure and place the hose on the uphill side of the plant so the water runs into the well and the berm slowly. By doing it this way, you will have to repair the well and berm less frequently. If you are watering with a bubbler or drip system, always make sure that the bubblers or emitters are placed on the upside of the slope and the plant so the water comes down the slope into the well and has a chance to penetrate the root zone located in the well and bermed area. Finally, if you are watering plants on a slope with Netafim (in-line emitter drip tubing), you can place the loops or grid of tubing throughout the well area, held in by the berm. The water will drip very slowly and be contained within the bermed well.
Having grass on slopes is discouraged because it is very difficult to keep your grass healthy without watering inefficiently. If you need to water grass on slopes, please carefully check out the section of our irrigation efficiency guide on cycle and soak.
By following these simple steps, you should be able to efficiently water and successfully plant on a slope.
Edible garden landscapes need to have dedicated valves so they can be watered more frequently than our average desert-friendly landscapes. These landscapes should not be watered at the same time as the rest of the drip zones.
The key to growing the best quality produce, fruit-bearing trees, shrubs and vegetables is having a consistent watering schedule that is maintained until harvest. If you are unable to install a new irrigation valve for your edible garden, you can connect it to your hose spigot with a spigot irrigation timer. We recommend the smart versions of these timers. Rebates are available.
We recommend using ¼” polyline with inline drip emitter tubing. Drippers should be located every 6” along the tubing for irrigation in both raised beds and veggie rows. The drippers require no maintenance since they are installed within the polyline. Each dripper is engineered with a little bit of copper that kills off roots that try to grow into the dripline. They are easily connected to a ¾” polyline flexible irrigation supply line. Metal irrigation stakes help keep everything in place.
All these materials can be purchased at local irrigation stores. Drip irrigation is not only the most efficient way to water your edible garden but it is also very affordable.
Typically, a conventional turfgrass yard includes a few large trees and some planting beds for flowers and shrubs around the foundation of the home. This type of yard often has a couple of existing irrigation valves for sprinkler irrigation. A conventional turfgrass landscape requires tremendous amounts of water to thrive in our region — a minimum of 40” (with an average of 50"-55”) of water per growing season, which is about three to five times more than what is provided by natural precipitation each year. This is why we do not consider a turfgrass yard a desert-friendly landscape.
Climate change is causing us to rethink our yards, and that includes yards with lawns. For a yard with a lawn to be truly desert-friendly, the amount and type of grass used must be considered. A desert-friendly turfscape should also have efficient sprinkler nozzles and pressure compensating sprinkler bodies to maximize the water that’s used to maintain the lawn.
We recommend that no more than 10% of your total yard is devoted to a lawn. Research from various universities in the Southwest and lawn seed producers (such as Pennington Seed) is now suggesting that New Mexico’s climate is no longer suitable for cool-season grasses to thrive. Instead, we need to make a shift to various warm-season grasses, which will grow well with significantly less water.
Cool-season and warm-season lawns are the two different categories of turfgrass lawns found in Albuquerque. Cool-season grasses (Kentucky bluegrass, perennial ryegrass and tall fescue) thrive between 65F and 75F degrees in the summer. They create a softer, darker green and lush-looking lawn. In Albuquerque, most lawns are composed of cool-season grasses that are cold-tolerant and green most of the year. They can withstand considerable amounts of foot traffic. One disadvantage is that they use a substantial amount of water in the summer months. Parkblend (a blend of cool season grasses) is the most common lawn in the Albuquerque metro area. It uses around 40” of water a year.
Warm-season grasses (Bermuda grass, blue grama, and buffalo grass), which thrive in 70F to 90F degrees, have been used in Albuquerque for many years. There are parts of town where they are quite prevalent. Warm-season grasses have a shorter growing season. They green up later and go dormant earlier than cool-season lawns. They are low maintenance and require less water than cool-season grasses.
Buffalo GrassBermuda Grass
Knowing what type of lawn or turfgrass is being installed or already being watered can make a significant difference in how much water should be applied. The key to choosing a turfgrass for a new area is to determine the one most suited to the specific needs of the landscape.
Water Budget (this includes 1,000 square feet of cool-season grass and a number of mature trees, shrubs and vines):
Most irrigation work can be done by the homeowner, except for one component. Tapping into your home's main water line needs to be done by a licensed contractor to ensure it is completed safely. To help homeowners know how to select and work with a contractor, we have provided the Irrigation Association's Irrigation Consumer Bill of Rights in the Appendix.
To make sure you have an efficient system, we highly recommend that you hire a professional irrigation designer to create a custom plan. Having a custom plan minimizes water waste and the chance of problems in the future and also helps ensure an efficient distribution of water, which reduces water usage. We also recommend asking a designer to produce a "call-out" list of all the parts required for the installation or renovation. This helps homeowners decide whether to DIY or hire a contractor.
SEPARATINGIRRIGATIONZONES&HYDROZONING
When you begin to plan a drip system, whether you’re installing a new system or retrofitting an existing system, it is imperative to design it so the drip valves are separate from your lawn valves. If you plan to grow a vegetable garden or water annual beds with a drip system, those areas also need to be on separate valves.
The next thing to do is organize your drip zones by plant watering needs. This means that higher water plants and lower water plants should be on separate valves (hydrozoning) whenever possible, so watering is much more efficient. Hydrozoning is not always possible when retrofitting an established landscape. In that case, you can adjust your water delivery with various sized drip emitters so plants with higher water needs receive more water per hour.
Check out our New Irrigation Efficiency Guide: Beautiful Landscapes with Less Water. Download the guide here.
