Trees are incredibly valuable and provide a wide array of
benefits, from increasing home values to improving mental health.
Unfortunately, Albuquerque has suffered large losses of trees in the past
decade. It’s more important now than ever to take care of your existing trees.
A common sight on spring evenings is seeing people with
their thumb on the hose, spraying the trunk of a tree. While it’s great to see
people caring for their trees, there is a better way to water them.
Trees have several different types of roots that serve different functions. Fine hair feeder roots are responsible for taking up water. Because these feeder roots are generally located near the tree’s canopy edge, this is where you want to apply water: a little inside and a little outside of the canopy edge.
TREE WATERING TIPS:
1. Hand watering
Turn your hose to a low flow or fast drip, so the water soaks into the soil before running off (try a hose end shut off valve). Set a timer and move the hose to different locations every 20 minutes starting 5 feet from the trunk to just outside the canopy edge. Small to medium trees will require watering at between 12 and 20 locations. Larger trees may need to be watered in sections over a few days.
2. Drip irrigation on desert friendly xeriscape
Growing healthy trees in a desert friendly xeriscape is possible using drip irrigation such as flag emitters. As trees grow, they require more resources in the form of soil rooting space and water. That means that as trees become established, drip irrigation emitters need to be shifted away from the original rootball (at the time of planting) out to the edge of the tree’s canopy. Additionally, the number and size (volume) of emitters needs to be increased as the tree grows. Most people don’t make these adjustments. Consider these strategies instead:
Plant an understory of groundcovers or flowering perennials within and beyond the tree’s canopy. The emitters used to water the groundcover plants will, in turn, water the tree. As the tree becomes larger it may eventually shade out the groundcovers, but the emitters should be kept in place to continue watering the tree.
Consider supplemental watering by hand in dry areas of your yard that are not covered by the drip irrigation system.
A similar strategy is to use professional landscape drip line (often referred to as netafim) in a grid or spirals in and outside of the tree’s canopy. This irrigation material requires less frequent maintenance and can be installed under mulch. As the tree matures, the drip line can be expanded and shifted to support the increasing needs of the tree. Understory plantings can also be used with this type of irrigation material.
3. Using sprinkler irrigation to water trees in a grass lawn
Most lawns in our area require nearly 40 inches of yearly irrigation to look good. So, it makes sense to plant a tree in the lawn to take advantage of all that water. Most of the large, beneficial trees in our city parks are grown like this. However, some species (like cottonwoods) respond to the shallow and frequent lawn irrigation by making shallow roots that protrude above the surface. These surface roots create tripping hazards. Damage to the tree can result from lawn mowers, too. Shallow roots also make the tree more susceptible to drought stress. Encourage tree roots to go deeper by occasionally (one-two times per month) running the lawn sprinklers for three or more cycles for a longer period. This will help to get water down deep, where it will remain in the soil longer and encourage roots to move deeper. Occasional deep watering in lawns also has the added benefit of flushing out salts accumulated from hard water and fertilizer.
Example of exposed surface roots. Author: Amos Arber, ASLA, ISA Xeriscape Incentive Inspector with the Water Resources Division for the Water Authority. Have a question about the article AskAnExpert@abcwua.org
Shredded woodchip mulch helps soil hold moisture and insulates plant roots on a frosty November morning. Photo credit M. Thompson.
One of the most frequent questions we get at NMSU Extension is, “Should I add fertilizer or amendments to the soil when planting?” The short answer is no. And the long-term answer is an even stronger no.
Soil amendments are materials that are
worked into the soil with the intention of improving soil physical qualities. But
it’s just not that simple. As City of Las Cruces Community Forester Jimmy
Zabriskie said when I asked if he ever recommends using soil amendments when
planting a tree, “Save your money for mulch.” Organic
mulch is
material that sits on top of the soil, providing an insulation layer that helps
control soil temperature, retain moisture, and suppress weeds.
When planting ornamental plants, the
recommended species are the ones with roots that are well adapted to our native
soils. They’re more likely to live long, sustainable lives in our native soils
without amendments. The bottom line: Always put the same soil you dug up right
back into the hole with the new plant, and top dress with a thick layer of
mulch.
Frosty cottonwood leaves add a nice layer on top of several inches of shredded woodchip mulch. Photo credit M. Thompson
As for fertilizers, slow and steady wins this race. As Albuquerque City Forester Joran Viers said recently at a tree planting demo put on by Tree New Mexico and The Nature Conservancy, it helps to think of our trees (and other plants) as marathoners, not sprinters. When fertilizer is applied to trees, they can grow too fast for their own good and are more likely to develop structural problems and other issues. Fertilizers are not recommended at the time of planting perennial plants, either, because we want the plant’s energy to go into root establishment at a healthy rate to support the aboveground growth. The growth hormones necessary for healthy root development are found in the root tips and are made by the plant itself, so adding root stimulator to living roots is not necessary or even helpful. (Side note: Rooting hormone is potentially useful when you’re trying to get roots to grow quickly from cuttings where the roots have been removed completely.) So hold off on fertilizing for at least a few years while your plants are setting down roots.
Research on all sorts of landscape plants has shown that by adding amendments (like organic matter or perlite) to your soil backfill, the initial, short-term results are good. But the interface between the amended soil and the native soil is bad news. Water doesn’t move well across the interface, and neither do roots. With time, the roots may be inclined to stay in the original planting hole and spiral around, so you end up with essentially a potted tree or plant with reduced growth rate, constant water and nutrient stress (because lateral roots never fully developed), heightened vulnerability to pests and diseases, and even an increased falling hazard (think root ball in socket).
Author: Marisa Thompson, PhD, is the Extension Horticulture Specialist for New Mexico State University and is based at the Agricultural Science Center at Los Lunas. For more gardening information, including decades of archived Southwest Yard & Garden weekly columns, visit the NMSU Extension Horticulture page (https://desertblooms.nmsu.edu/), , follow us on social media (@NMDesertBlooms), or contact your County Cooperative Extension office (https://aces.nmsu.edu/county).
We scoured the internet, met
with local experts, and pulled together a great educational resource list for you.
When you’re ready to dig into all there is to know about landscaping in New
Mexico, these resources are ready for you.
Agaves, Yuccas and Related Plants. Mary Irish, Portland
Oregon: Timber Press, 2000.
A Field Guide to the Plants and Animals of the
Middle Rio Grande Bosque. Jean-Luc Cartron, David Lightfoot, Jane
Mygatt, Sandra Brantley and Timothy Lowrey, Albuquerque, New Mexico: University
of New Mexico Press, 2008.
Landscaping with Native Plants of the
Southwest. George
Oxford Miller, Minneapolis, MN: Voyageur Press, 2007
Native Plants for High-Elevation Western
Gardens. Janice
Busco and Nancy R. Morin, Golden, Colorado: Fulcrum Publishing, 2003.
Natural by Design. Judith Phillips, Santa
Fe, NM: Museum of New Mexico Press, 1995.
When we think of the word evergreen, many of us think about pine trees, cedars and junipers. However, an evergreen is simply any plant that remains green all year long. These plants are welcome fixtures in our winter landscapes, too. 505Outside highlights these essential elements of the greater Albuquerque area landscape by asking local plant experts which ones they love. Below are some of their favorites.
When the last of the yellow and purple perennial colors fade away in the fall, these (and other) evergreen plants provide the structure that holds landscapes together through the winter months. Don’t forget to include evergreen plants in your landscape for year-round interest.
Now that the weather is colder, curl up with a book and
learn more about our global and local water resources.
Here are a few of my favorites to get you started. If you’ve
got a water book to recommend for future newsletters, please email me at kyuhas@abcwua.org
For a thought-provoking read about the effect of rising sea
levels throughout the world, pick up The Water Will Come: Rising Seas,
Sinking Cities And The Remaking Of The Civilized World by Jeff Goddell. He
uses a blend of science and first-person accounts to create an engaging and
informative read. This book made many top book lists when it was released in
2017.
Replenish: The Virtuous Cycle of Water and Prosperity by
Sandra Postel explores many projects, including some in New Mexico, that work
with nature to enhance and preserve the earth’s water resources. Ms. Postel is
a world-renowned water expert we’re lucky to have living with us here in New
Mexico.
Another New Mexico book is A Song for the River by
Philip Connors. This is beautiful, meditative exploration of his time in the
Gila National Forest and of the Gila River. Those who want more of Mr. Connors’
writing on the Southwest should also pick up the multiple award-winning Fire
Season: Field Notes from a Wilderness Lookout.
Finally, for those who want to get started dreaming about their
spring garden, try Growing the Southwest Garden: Regional Ornamental
Gardening or any of the other gorgeous, picture-laden titles by Judith
Phillips, another author we are lucky to call our own. Her beautiful books can
be found at local bookstores and libraries.
Author: Katherine Yuhas, Water Resources Division Manager with Albuquerque Bernalillo Water Utility Authority
Some of our best landscaping practices can be learned from Mother
Nature. Every autumn, leaves fall to the ground, sheltering the soil and beneficial
organisms, returning organic matter back to the ground, and perpetuating the nutrient
cycling essential for good plant health. This year we want you to think about leaving
those leaves in your garden. When we allow leaves to follow their natural life cycle,
we can enjoy a colorful tapestry on our landscape as well as all the benefits provided
by an organic mulch.
With these tips, you can spend less time raking leaves into plastic
bags and enjoy more fall fun:
When designing your landscape, make your pathways
and hardscapes above the level of your planting areas. The wind will naturally blow
leaves into the low spots where they will support soil and plant health. This also
happens to be a great water harvesting strategy.
Use organic mulches instead of gravel. Organic mulches
such as wood mulch are visually accommodating to leaf litter (meaning you won’t
notice them as much), allow for the leaves to decompose into the porous spaces and
build soil. Leaves break down to virtually nothing in this environment. If you prefer
a tidy look, follow up with a light topdressing of mulch for a finished appearance.
If the leaf load is too much to manage directly under
your trees, rake the leaves a little off the top and distribute them throughout
your yard – ideally to a compost heap where the leaf litter will become an excellent
soil amendment for your spring garden. Note: if you have chickens, they will turn
your leaves into next to nothing in a matter of days.
If you have a lawn, run your lawn mower over the
leaves and let the crumbled litter work its way back into the soil. The addition
of organic material to your lawn in the fall will give a boost to your lawn when
it wakes up in the spring.
There are a few instances when you should remove fall
leaf litter. Leaves from diseased plants – particularly fruit trees and roses -
should be taken to a compost facility to be recycled. While you can try to compost
them yourself, be advised that most backyard compost piles do not reach a high enough
temperature to kill pathogens. Also, xeric plants that grow naturally in rocky terrain
will be susceptible to crown rot if organic material is piled up around their bases.
Leaving fall leaves has another great benefit – it is carbon neutral. Carbon is sequestered in the soil, leaf blowers and plastic bags are removed from the equation, leaves don’t end up in a landfill or produce methane gas, and no transport to the landfill is required. It’s a win-win when we let Mother Nature be our guide.
Author: Paulina Aguilera-Eaton, Water Conservation Specialist with Albuquerque Bernalillo Water Utility Authority
