With recent news headlines (https://abcnews.go.com/US/happen-colorado-river-system-recover-historic-drought/story?id=98475953) warning of the extreme drought conditions hitting the western U.S. and the region that makes up the Colorado River basin, cutting water use has become top of mind for many citizens and leaders in Colorado and beyond. One city in Colorado has approved a plan to cut water use in the face of this historic drought, and this plan is raising some eyebrows and generating its own headlines due to its potential impacts.
In the summer of 2022, the city council for Aurora (Colorado’s third largest city), approved restrictions on high water turf lawns for all new construction. Originally proposed by Aurora mayor Mike Coffman, all ten members of the city council voted to approve the new ordinance which limits the amount of turf lawns in new developments and golf courses. (https://www.denverpost.com/2022/08/23/aurora-limits-grass-lawns-golf-courses-water-usage/)
The ordinance prohibits water guzzling turf lawns in common areas, medians, curbside landscape and front yards. In back yards, lawns must be equal to or smaller than 45% of the area, or 500 square feet, whichever is smaller. However, an exception was included to allow front yard turf lawns for residences whose backyards are too small to fit the 45% or 500 square feet threshold.
Perhaps most importantly, the ordinance restricts turf from being used merely for decorative purposes in common areas unless it is for use in “active or programmed recreation areas.” The skinny strips of lawn often found in older commercial developments which are inefficiently irrigated as water over-sprays wastefully on to nearby walks, streets and parking lots, will hopefully become a relic of the past.
Wasting water in a parking lot.
Considering that the typical high-water lawn needs 25″ of water annually to look good and green, and Aurora (as well as most of the front-range urban corridor of Colorado) only receives 15″ of natural precipitation all year, reducing or eliminating non-active or un-programmed turf lawns is a very easy way to reduce urban and suburban water use.
This is why another recent headline grabbing story regarding reducing turf lawns was welcome news. In June 2022, the State of Colorado passed a bipartisan-sponsored measure that will encourage property owners across the state to ditch their water-wasting turf lawns (https://leg.colorado.gov/bills/hb22-1151).
The legislation is intended to use state funds ($2 million) to financially incentivize the voluntary replacement of irrigated turf with water-wise landscaping. The bill, HB22-1151, requires the Colorado water conservation board to develop a statewide program that would distribute funds to various “local governments, certain districts, Native American tribes, and nonprofit organizations” for lawn replacement programs. Those funds could then be used to pay property owners to reduce their landscape irrigation by transitioning away from high water turf lawns, towards more climate appropriate landscape treatments. The funds could also go towards expanding some existing programs that already pay property owners to replace water-thirsty lawns, about $1 to $3 per square foot of removed sod. Most of these rebates are only offered in cities in Colorado and not unincorporated areas. One goal of this legislation is to broaden this type of program to other areas in the state.
An example of a water saving landscape renovation at a multi-family property in Aurora, CO.
While $1 to $3 per square foot of removed sod may seem generous, there are reports of some landowners in California getting lawn replacement rebates up to $6/sf. (https://www.cnn.com/2022/08/19/us/california-drought-lawns/index.html). Interestingly, some of the rebate programs in California also require installation of rain barrels as well as turf lawn replacement. That is an intriguing idea for rebate offering entities in Colorado to consider, especially since rain barrels only became officially legal just a few years ago.
Researchers at Colorado State University estimate that landscapes account for at about 55% of the total annual water use for a typical single family home in Colorado.
Typical Colorado household water use; CSU extension
And most of this goes towards lawn irrigation. In the city of Denver for example, it’s estimated that nearly 25% of the city-wide entire annual water consumption is sprayed on high-water turf lawns. (https://denverite.com/2019/05/06/denverites-can-use-120-million-gallons-a-day-to-water-their-lawns/) Considering that lawns are only irrigated about half of the year or less in Colorado, that is a lot of water that could easily be saved if more lawns were changed into climate appropriate landscape treatments.
Let’s hope that the recent passage of Aurora’s lawn restriction as well as HB22-1151 helps usher in a more water conserving and water conscious future in Colorado and other states in our drought prone region. This won’t translate into a complete disappearance of high-water turf lawns. However, for the sake of our rivers, aquifers and reservoirs, it means that these water-hogging green carpets must be used wisely and judiciously in the designed landscapes of the future.
Example of beautiful low-water groundcover alternatives to high water turf lawn.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Denver Water customers received news last year that the pH of the water delivered to them by Denver Water would be adjusted from near neutral (pH 7.5) to slightly more alkaline (pH 8.5), which began in Spring 2020.
The motivating reason for this change is for improved human health, which is highly commendable (more alkaline water is less prone to leach lead from pipes into people’s drinking water; lead is toxic to human health).
But, this announcement has many in the Landscape Industry wondering what impacts this may have on irrigating landscape plants, as well as indoor plants, and how it may affect water conveyance equipment (irrigation systems, etc).
A cursory investigation via the internet seems to indicate that the possible impacts from higher pH water on irrigation systems and the plants that receive that more alkaline water are:
Increased mineral deposits on irrigation equipment as well as pots, planters, etc. For drip emitters this can be very problematic as the water emits at such a low and slow rate that calcium scale build-up could end up clogging the emitters.
Reduced absorption of minerals and nutrients by the plants.
Most of the soil pH in Colorado’s Front Range are alkaline, so it is possible that this increase in pH will have little or no effect on plants that are already suited or adapted to the native soils of our area. But for plants that don’t do well in alkaline soils, will this more alkaline water be the factor that pushes those plant over the edge? Is this such a bad thing if those plants aren’t suited for our soils (and climate) to begin with?
What are some actions you can take to mitigate the problems of more alkaline water?
Water more deeply and less often. Frequent and shallow waterings may cause more build-up of salts and minerals like calcium.
Use alkaline adapted plants in your landscape rather than plants that need acidic soils. Generally speaking, most native plants for our region (Colorado’s eastern Front Range) are well adapted to alkaline soils.
Check your irrigation equipment for hard water scale build-up. Clean or replace drip emitters that are clogged with scale to ensure proper water flow.
Add Acidifying materials to the soil, like granules available from garden stores? Some experts seem skeptical of this method, saying it is very difficult to have much impact on the total alkalinity of our native soils.
Add more organic matter such as compost? Aside from most xeric adapted plants as well as plants native to our region, many of the standard landscape plants benefit from added compost for multiple reasons. Adding compost to soil can lower the pH (more acidic) as well as aid in water retention, soil texture and provide nutrients to plants.
You may wonder if softening your water via chemical means is a good option. Several experts say this is not a good way to lower the pH of the water for plants because softened water has higher salt content, which is also problematic for plant health.
Some articles sourced on the internet mention lowering the pH of the water you irrigate your houseplants with, by adding vinegar. This may work for a small watering can used on houseplants, but for landscape plants this is simply impractical. Could an in-line fertigation system be used with an acidifier such as vinegar on landscapes? We here at ODG are uncertain about this option, but it seems like an intriguing, if also risky, option.
Time will tell how our landscapes react to the increased alkalinity of our water supply. We hope the effect is minimal, because gardening in our high altitude semi-arid climate is challenging enough as is!
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
As water prices rise, and the climate warms, water conservation is becoming even more important. Colorado’s current population is estimated to be 5,695,564, nearly 700,000 higher than in 2010. That 13.2 percent growth is the fourth highest among all states over that time period.
All these new residents continue to put a strain on water supplies. It makes perfect sense then, to encourage Xeriscape, which, as we’ve written in the past (the-7-principles-of-xeriscape-revisited-30-years-later), is a form of landscape design that requires much less water.
We are pleased to hear of HB19-1050, a new bill in the Colorado General Assembly, that encourages the use of Xeriscape in common landscape areas.
Section 1 of the bill augments an existing law that establishes the right of unit owners in common interest communities to use water-efficient landscaping, subject to reasonable aesthetic standards, by specifically extending the same policy to limited common elements, which are owned by the community and available for use by some but not all of the unit owners.
Sections 2 and 3 extend existing water conservation requirements, currently applicable only to certain public entities that supply water at retail and their customers, to property management districts and other special districts that manage areas of parkland and open space.
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Design Group, Colorado Landscape Architects. For more information about
our business and our services, click here.
Japanese beetle eating an Oenothera flower at the Denver Botanic Gardens.
Gardeners around Colorado’s Front Range are coming face to face with a new foe in our landscapes. Japanese beetles have been a pest for years in U.S. gardens in the east, south and mid-west. It is only relatively recently that the feared invasive pest has made its presence known in Colorado.
The beetles (Popillia japonica) are believed to have entered North America via New Jersey in 1916, probably hitchhiking on ornamental nursery stock from Asia. They are voracious feeders, doing damage to trees, shrubs, perennials, annuals and turf grass. Some of the 300 favorite food plants of the adult Japanese beetles are roses, Virginia creeper, grape vines, raspberries, linden, elm and fruit trees. The sign of their destruction is skeletonized foliage and flower petals that have been devoured. The adult beetles feed during the day, preferring hot and sunny days.
Japanese beetle on a “skeletonized” grape leaf at the Denver Botanic Gardens.
The beetle’s one-year life cycle seems tailor made for a traditional lush turf and shrub landscape. They spend winter underground as a grub, feeding on turf grass roots, creating dead patches in the lawn. In June they begin to emerge as adults ready to feed on the flowers and leaves of plants. The adults can be found feeding on plants as late as September. In addition to feeding on your landscape plants, they might be seen mating on those plants. After mating, females will move to turf grass lawns to dig into the soil to deposit their eggs. After depositing eggs, the females will resume feeding on host plants. The females will return to the lawn to lay more eggs. Up to 60 eggs can be laid by each female beetle during her 4-8 week life span.
Back in the turf grass soil, the eggs will hatch and the Japanese beetle larvae will emerge and move to the grass roots to feed. The larvae are most susceptible to drying out and dying when young if the soil dries out. That is one reason some experts advise against over watering lawns in mid to late summer. The larvae will develop rapidly, causing much damage to the turf grass roots, eventually killing some of the turf grass plants. The larvae feed on the grass roots until the temperature drops below 60 degree F. The larvae move deeper down into the soil to overwinter. Once the soil warms up in spring, the larvae move back up through the soil to resume feeding on the grass roots for about 4 to 6 weeks. After that, they begin to pupate. A couple weeks after pupation, the adults will emerge from the soil to feed on leaves and flowers, mate and start the cycle all over.
The worst damage caused by the Japanese beetles seems to be to lawns, where the larvae can cause dead patches. It appears the damage to shrubs and trees is mostly cosmetic, and will not kill those plants. However, this cosmetic damage can be significant and will upset most gardeners.
Unfortunately there is no magic bullet to control Japanese beetles in your landscape. If you discover them when they first arrive, using manual methods to collect them is a wise choice. Do not crush them, or the chemicals released upon squishing will attract more Japanese beetles to your yard. Try collecting them in a jar of soapy water. Traps are not recommended because they also attract more beetles to your yard. Pesticides may be effective at controlling the beetles. However some systemic pesticides have been linked to death of beneficial pollinating insects such as bees. For more information on the safe use of pesticides and other methods to control Japanese beetles, visit the Colorado State Extension webpage on the subject. Some experts advise the application of grub killing pesticides to lawns to kill the Japanese beetle larvae and keep your turf from being destroyed. The extension does say this about trying to control the larvae of Japanese beetles: “Some cultural practices can limit damage and applied chemical or biological controls may also be useful. However, control of Japanese beetle larvae in a yard will have very little, if any, effect on the number of Japanese beetle adults feeding on trees, shrubs and garden plants. The insect is highly mobile so that problems with adult beetles typically involve insects that have moved a considerable distance.”
As mentioned earlier, dry turf soil during the egg laying season (mostly in June & July) will keep some larvae from surviving to become adults. Some experts recommend drying out your lawn and letting it go dormant during the typical Japanese beetle egg laying time, and resuming watering after the eggs have been layed. This would seem a challenging approach to the problem as most people prefer a green, non-dormant lawn during the time of year when a lush lawn is much desired. The extension service does recommend that keeping lawns well watered after egg laying (and once the older larvae are present and most actively feeding) may help the turf survive root injuries caused by larval feeding.
It would appear that typical xeriscape plants are not usually favored by the beetles. This is yet another reason that a xeric and regionally appropriate landscape design is a good approach to follow in Denver and Colorado in general.
Let’s hope we can keep this exotic and invasive pest at bay, and not let it become an established nuisance.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Starting on August 10, 2016, it is no longer illegal for homeowners to collect the rain (or other precipitation) that has fallen on their roofs. In May 2016 Governor John Hickenlooper signed a law (House Bill 16-1005) that allows residential properties and multifamily residences with four or fewer units to use up to two rain barrels, located above ground, with a combined storage capacity of 110 gallons.
Rain barrels can only collect precipitation from rooftop downspouts, and the collected water can only be used on the same property from where it was gathered. The collected water can only be used for outdoor purposes, such as watering outdoor plants. Collected water in rain barrels can not legally be used for drinking or indoor uses. Additionally, it should be known by rain barrel owners that operating a rain barrel does not constitute a water right. There is language in the bill that the State Engineer “may curtail rain barrel usage” if a water right holder can prove that the use of rain barrels has impacted their ability to receive their entitled water. In fact, in the bill it says the State Engineer must report to agricultural committees in the legislature in the year 2019 and 2022, on “whether the allowance of small-scale residential precipitation collection pursuant to this article has caused any discernible injury to downstream water rights.”
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
