Mulch is any material laid on the surface of the soil to improve growing conditions. Mulchinsulates plant roots from both heat and cold, reducing moisture loss from the soil by evaporation, feeding beneficial soil microorganisms that enhance plant growth, and improving soil health. Because organic mulches were once alive, they contain essential nutrients, minerals, and energy that nourish the soil ecosystem as they decompose. An important consideration when using mulches is to skip using landscape fabric, which prevents both the rich organic matter created by decomposition from working its way back into the soil and rainwater from soaking into the soil.
Below are the basic types of locally available organic mulches that we recommend. Remember to install to a depth of 3”-4” over bare dirt.
Wood chips: Wood chips are chipped pieces of trees. This is a long-lasting mulch that decomposes slowly over bare dirt, retains moisture, and prevents weeds. Most wood mulches available on the market are chipped flat and consistent in shape in size. These are great in areas that receive foot traffic as they compact down to a firm surface.
In areas of higher wind exposure or periodic inundation with water, use a shredded wood mulch that is more irregularly shaped and sized as the pieces will knit together better. This type of mulch can be recycled yard waste and tree trimmings as well as commercially available, locally processed wood products.
Pecan Shells: This long-lasting mulch has a nice color and good texture. It is very slow to break down into the soil. However, it attracts birds and rodents and blows in the wind unless partially cultivated into the soil. It also tends to mat together, creating a crust over the top of bare dirt.
Straw: Straw breaks down quickly so it is most useful for mulching vegetable beds where it is renewed as crops are replanted. It is a good general mulch for winter protection and can be used on paths between vegetable rows. Keep in mind that it may carry weed seed.
Pine Needles: Pine needles are a very good mulch. They are light, airy, and attractive but can be a fire hazard. These needles are safe to use as mulch around most plants, especially perennials, in your garden. Because pine needles contain high levels of resins, they repel water and decompose much more slowly than leaves from most deciduous trees. Because of their shape, they don’t become moist or compost rapidly. This makes them especially useful in areas where you will not be digging frequently. The fragrance of pine needles on sunny days is also an added benefit when they are used as garden mulch. No need to be concerned that pine needles are too acidic for use in our gardens. The added acidity, which happens slowly, is beneficial to our soils. They are very slow to compost, so they are often a better mulch than compostable material.
Other Mulches:
Bark: Large 2”-4” bark pieces are not recommended because they take too long to break down. The mulch made from bark tends to be lighter and can tend to migrate more easily. The bark is naturally water-resistant, so it has minimal value in feeding soil microorganisms and improving soil health.
Crushed Stone, Crusher Fines, or Decomposed Granite: Crusher fines come in a variety of aggregate colors. They are recommended for use as pathways and patios or as mulch under plantings for heat-loving, desert-accent plants.
Gravel Rock and Cobble: While you see these used throughout the city in landscapes, they are best used to prevent erosion on steep slopes or in swale areas. They are difficult to maintain without regular weeding or pre-emergent treatments.
Useful tips: Mulch typically packs down over time. Use a 3”-4” layer of mulch, which is about one yard of mulch per 100 square feet. “Spend an hour deepening the organic mulch and save several hours of weeding.” By Judith Phillips
While a subsurface drip irrigation system can last from twelve to fifteen years, especially if it is maintained well, some of the system’s components may need to be replaced or repaired through the years.
A controller, for example, is subject to UV degradation if it is installed outside. Controllers need to be properly sealed and monitored for any inside moisture that can corrode the system’s components. Older controllers (pre-2000) can be difficult to set and have limited choices for how to water, which can make watering inefficient when using these controllers. Since Water Sense Smart Technology controllers are more efficient, we recommend switching to this technology. We offer rebates to help you make that upgrade.
Drip irrigation tubing is also known to degrade when exposed to UV light. According to landscape professionals in the Albuquerque area, you can expect the tubing to last for about ten years if it is buried. If tubing is placed on the surface of the ground, it generally won’t last a decade due to several factors, including exposure to UV light and an increased risk of freezing and splitting.
Emitters have various lifespans. Button emitters tend to clog less but need replacement when that happens. Flag emitters clog more often from mineralization but can be flushed.
Another reason for emitter and drip line failure is damage from humans, dogs, rabbits, ground squirrels and pack rats.
Regular maintenance is the best way to increase the lifespan of an irrigation system. Click here for our free irrigation checklist to help keep your system in tip-top shape.
Author: Richard Perce, Irrigation Efficiency Specialist with the Water Conservation Department for the Water Authority. Research: USGA.org and Colorado Extension Service Have a question about the article?
Albuquerque ranks third, after New Orleans and Houston, among cities with tree loss. Our trees are dying because they aren’t being watered properly or at all. How should we water established and mature trees?
To address this problem a landscape architect and a professional landscaper put together a Tree Watering Irrigation Kit that allows you to water established trees more deeply and consistently.
It’s easy for homeowners to assemble a similar kit that attaches to a hose spigot using the parts below, from left to right.
Startwith a hose bib vacuum breaker, which prevents water from siphoning back into the potable water system. Next in line is a hose water timer that works like a kitchen timer, opening and closing a valve at a pre-set time. Instead of a hose water timer, consider using a WaterSense Smart Controller (a rebate is available for this controller). Attach a female-to-male hose swivel converter to the timer or controller. This converter allows you to pop on a pressure regulator that drops our city’s water pressure down to 30psi, which is the best pressure for a drip system. After the pressure regulator, attach an adapter that connects to the ½” inline dripline. The inline dripline comes with 1gph emitters that are spaced every twelve inches. This allows the water to drip consistently and efficiently directly into the ground, deeply soaking the roots of the tree.
Once you have your system installed, a good rule of thumb is to set up a 45-minute run time. To know how often to water, follow the Seasonal Watering Recommendations .
The end cap (pictured below) is installed at the end of the inline drip tubing. This can be opened to empty the line of water and prevent freezing.
Do you want to learn how to harvest rainwater to support a beautiful, regionally adapted, low -water-use landscape in your yard? A new video series launched in June provides instruction on how to design, install, and maintain residential-scale, passive rainwater harvesting features. In passive water harvesting, rainwater is conveyed directly to a landscaped area and infiltrated in the soil.
Landscapes that incorporate rainwater harvesting and native/drought-tolerant plants require little supplemental irrigation. Rainwater harvesting provides the deep watering that large plants like trees and shrubs need in our hot and dry climate. Capturing and infiltrating rainwater also reduces runoff that carries pollutants to the Rio Grande River.
In this series, you will learn how to construct some of the most common passive rainwater harvesting features in residential applications – basins, swales and soil sponges. The training addresses site selection, sizing basins, grading swales, installing soil sponges for enhanced infiltration and selecting plants. It is presented by four local experts on rainwater harvesting and arid-adapted gardens: Jim Brooks, Tess Houle, Judith Phillips, and Hunter Ten Broeck.
The video series was developed through a collaboration between Bernalillo County, Ciudad Soil and Water Conservation District, and the Arid LID Coalition, and included the installation of a Rainwater Harvesting Learning Landscape at the Gutiérrez-Hubbell House History and Cultural Center. Please visit the Rainwater Harvesting Learning Landscape in person to see an example of a rainwater harvesting feature designed for our arid climate.
Fall can be a great time to plant, especially if you are planting higher elevation and temperate climate plants that are adapted to cooler, more humid growing conditions. In the fall, the soil is still warm enough to encourage roots to develop so watering properly makes a big difference on preparing them to survive in the winter season. What to plant? Most conifers, shade trees, cool season grass and moisture-loving fruit and ornamental trees, such as crabapples, apples and pears, are a great selection for planting in this autumn.
What not to plant this fall? The answer is plants from desert ecosystems like southern New Mexico and the Mediterranean natives. Their newly planted roots are less able to survive our winter cold. The same is true for perennial wildflowers and warm season grasses. These should be planted in the spring through early August. Succulents are another group of plants that thrive after settling into the garden during the warmer part of the growing season, so wait until the spring to plant them.
Knowing what to plant at this time of year will give you that edge you need to grow healthy plants!
Author: Judith Phillips, owner of Design Oasis, landscape designer, and garden writer with 30 years of experience designing arid-adapted and native gardens in the high desert. Photography:Plants of the Southwest. Have a question about the article? AskAnExpert@abcwua.org
Did you know that half of Albuquerque homeowners do not have an irrigation system? We’ve been talking to hundreds of homeowners, and it turns out that the reason they haven’t installed one in their yard is they think an irrigation system for a typical lot (1/8 acre or 10,000 sf) will cost $5,000 or more. The good news is this is a myth! The cost for one fully installed irrigation drip system plus a controller/timer is between $1,350 and $1,900. Prices will vary depending on the size of your yard, the complexity of your water connection and if you want to add additional valves for irrigating plants with different watering needs, such as existing mature trees, vegetable beds, container plants or a turf grass lawn.
Here is what a typical irrigation system looks like. Do any of these elements look familiar to you? Perhaps you have a residential backflow preventer in your own yard and didn’t realize it or you thought it didn’t work because you’ve turned on the timer in your garage and nothing happens.
Many homes already have one or a couple of residential backflow preventers in the yard that are no longer in use. A local irrigation contractor usually can get those back up and running and include a new stub out for drip irrigation.
For those homes that don’t have any existing irrigation remnants, you’ll need to start from the beginning. One drip irrigation system is generally all you will need in a desert-friendly xeriscape for a 1/8 acre or smaller yard. Drip irrigation is the recommended method of delivering water to all your plants and trees (but not turf grasses).
You’ll want to install one backflow preventer with one valve to run the drip system in the yard. A ¾” distribution polyline is connected to the valve. The polyline, which winds all around the yard, has ¼” spaghetti tubing connected to it so water gets directly to the plants. Due to our typically high water pressure, most drip irrigation systems require a pressure regulator to slow the water pressure, thereby reducing the chance of the drip emitters getting popped off the line.
Here is a breakdown of the costs:
One automatic residential backflow preventer with valve and pressure regulator with stub out to future dripline. $600-800 installed (includes parts and labor).
¾” dripline polyline connects to the stub out of a new valve or from an existing one and winds around the yard. Add ¼” spaghetti tube with drip flag emitters on the end to water each plant in your yard. $400-600 installed (includes parts and labor).
One automatic irrigation controller/timer (Smart Controller that connects to the Internet and your smartphone). $350-$500 (includes parts and labor) (rebates available)
A regular controller costs $350 (includes parts and labor).
Before hiring an irrigation designer and/or contractor, it’s advisable to ask them specific questions so you can make wise choices about design options and the kind of equipment you need.Click on this link to access a helpful guide put together by the Irrigation Association as developed by Cal Poly, San Luis Obispo. Adding an irrigation system (especially a drip system) means watering your plants using the least amount of water to provide optimal health. It is making sure that every drop of water you use goes to where it is needed and can be used most effectively by your plants. An irrigation system conserves water, produces a healthier landscape, saves time and is not as costly as you think!
Author: Jill Brown, ASLA. Landscape Architect and Owner of My Landscape Coach The prices quoted here are based on my experience as a landscape professional in the Albuquerque market. Prices will vary, of course, on size, complexity, and availability. Have a question about the article? AskAnExpert@abcwua.org
