Low voltage landscape lighting is a great way to add evening functionality to your home landscape, as well as highlight and enhance some of those landscape elements at night. But it’s also important to consider whether these light fixtures may be adding to the growing light pollution problem that is impacting our world more and more each day, or to be more exact, impacting each night.
What exactly is light pollution and why is it a problem? The International Dark-Sky Association defines it as: “The inappropriate or excessive use of artificial light – known as light pollution – can have serious environmental consequences for humans, wildlife, and our climate.” Light pollution keeps us from having the ability to view the stunning vistas of the night sky that have delighted and inspired our ancestors for millennia prior to the advent of artificial lights. But its not just stargazing that is compromised by nighttime light pollution. Artificial lights can harm wildlife such as insects, migratory birds, turtles and mammals, by disorienting them, distracting them so they are more easily preyed upon, or even disrupting migrations leading to exhaustion or starvation.
Light pollution has grown so much over the recent decades that researchers have concluded that “more than 80% of the world and more than 99% of the U.S. and European populations live under light-polluted skies. The Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans. Moreover, 23% of the world’s land surfaces between 75°N and 60°S, 88% of Europe, and almost half of the United States experience light-polluted nights.” (https://www.science.org/doi/10.1126/sciadv.1600377#T1)
The International Dark-Sky Association lists the components of light pollution as:
Glare – excessive brightness that causes visual discomfort
Skyglow – brightening of the night sky over inhabited areas
Light trespass – light falling where it is not intended or needed
Clutter – bright, confusing and excessive groupings of light sources
The IDA has a list of 5 rules to consider when planning for landscape lighting:
1. Useful
Use light only if it is needed
All light should have a clear purpose. Consider how the use of light will impact the area, including wildlife and their habitats.
Consider using reflective paints or self-luminous markers for signs, curbs, and steps to reduce the need for permanently installed outdoor lighting.
2. Targeted
Direct light so it falls only where it is needed
Use shielding and careful aiming to target the direction of the light beam so that it points downward and does not spill beyond where it is needed.
3. Low level
Light should be no brighter than necessary
Use the lowest light level required. Be mindful of surface conditions, as some surfaces may reflect more light into the night sky than intended.
4. Controlled
Use light only when it is needed
Use controls such as timers or motion detectors to ensure that light is available when it is needed, dimmed when possible, and turned off when not needed.
5. Warm-colored
Use warmer-color lights where possible.
Limit the amount of shorter wavelength (blue-violet) light to the least amount needed.
And the International Dark-Sky Association has this summary that is a good mantra to consider if you want to keep your outdoor lighting from causing unnecessary light pollution: “Light where you need it, when you need it, in the amount needed, and no more.”
Our landscape lighting plans don’t have to make the light pollution crisis much worse than it already is. We can use landscape light judiciously around our properties. We can use fewer up-lights and more down-lights. We can keep the light level low and the light color warm. And we can use timing devices to turn off the brighter landscape lights when the pool party or garden fete is over, the guests have gone home, and we’ve gone inside for the night.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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.
Once upon a time, there was a castle guarded by soldiers. Enemies obscured by the trees would sneak close to the castle, so the soldiers reduced the threat by removing the trees. Without the trees, the land filled in with grasses, thyme, and chamomile. Animals began to graze in these new fields, keeping the plants low. The soldiers could see clearly across the land, and the sheep were fat and happy. The castle prospered, and everyone who visited wished their land could be so grand. The other land owners cut down their trees and filled in their land with grasses. The smell from the grazing animals wasn’t ideal, so they brought in men to cut the grasses low instead.
The “green carpet” surrounding the finest castles and estates in the 16th & 17th century became a status symbol, and planted the seed for the sod lawn we’re all familiar with today.
In the United States after WWII, automobile technology and availability took off. With the open road ahead of them, well-to-do folks left the cramped urban conditions of the cities, moving outward to new suburban neighborhoods.
Planners like Frederick Law Olmsted and Abraham Levitt gave the people sprawling neighborhoods, with acres of lush green grass. With the popularity of the 2-day weekend on the rise, homeowners indulged in their green Edens. This ignited a new chapter for the centuries old status symbol of the turf lawn – now repurposed for mini-golf and lawn bowl rather than spying enemy invaders and feeding livestock.
“No single feature of a suburban residential community contributes as much to the charm and beauty of the individual home and the locality as well-kept lawns” – Abraham Levitt
Ingrained into the new vision for the American Dream, well-kept lawns became the golden standard. With an estimated 30 to 40-million acres of the United States serving as an irrigated sod lawn today, this status symbol is butting heads with our resources and priorities.
The cold hard truth about lawns are that they are a water hog, high maintenance (what other non-food-production plants do you cut weekly, fertilize seasonally, and treat with chemicals?!), lawns are a food desert for animals & insects, and they do nothing for our groundwater while the water runoff often pollutes creeks and streams with high nitrogen fertilizers, causing harmful algae blooms. All of that lawn maintenance also creates air pollution and noise pollution from mowers, blowers, and trimmer equipment.
A renovation project where Outdoor Design Group helped our client reduce their turf lawn.
But lawns can be great in the right location!
This is where “active-use” vs. “passive-use” spaces come into play. Lawns can be very durable, and are amazing for active children and pets. Maintaining a lawn to play and entertain on is a lovely idea. Kentucky Bluegrass has been a popular turf choice for decades, but climate suited alternatives like Dog-Tuff Buffalo Grass, Bermuda grass, or “steppable perennial lawns” made up of creeping thyme or clover can serve the same purpose as high-water turf lawns with fewer drawbacks. While choosing the right type of lawn for your environment is a start, reducing the overall amount of lawn is still the key to a progressive and sustainable landscape. Maintaining any type of lawn on the side or front of your house where no-one ever spends their time is wasteful for you, your wallet, and the environment.
Steppable groundcover used with other perennials, step stones and mulch.
Consider ditching the golf-course-quality front-yard peacocking and save that neighborly competitiveness for the holiday light display. Instead, beef up your shrub beds, add some neat planters, and opt for native seed mixes that include drought-tolerant grasses & wildflowers. Keep your lawn only where you will use it, and plant a nice tree just west or south of it to keep it cooler and healthier during hot sunny days.
A front yard filled with a diversity of ornamental grasses, perennials, shrubs, landscape rock and mulch.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Whether you’re an experienced or an inexperienced gardener, you’re probably aware of fall planted flowering bulbs. Tulips, daffodils, crocus, alliums, hyacinth and other “fall planted/spring blooming bulbs” have become very iconic harbingers of the advent of spring season. However, there’s a large assortment of flowering bulbs that make a spring-time appearance in garden retail stores, providing their own form of welcoming the passing of winter and the arrival of a new gardening season. The so-called spring planted flower bulbs may be lesser known to the novice gardener, but can be almost as valuable as the fall planted bulbs. These summer blooming plants can be used to place spots of color in-between perennials and shrubs in your landscape. Planted in Spring, these bulbs emerge to provide beautiful flowers throughout summer and fall, with exact flowering times varying per species and cultivar.
In fact, the spring planted bulbs are not all true bulbs. Some may be corms, rhizomes or tubers, which are all different types of storage organs that plants have evolved over time. It is these clever little storage devices that have allowed people to dig them up during plant dormancy, and package them up to be shipped to garden center stores around the world. Some of the spring planted bulbs are perennials, but most are not, at least in the USDA hardiness zone that Denver finds itself in.
Crocosmia corms.
Out of the many types of spring planted ornamental bulbous plants available in your local garden center, I cover three common types here in this post.
Perhaps the best known spring planted bulb is the gladiolus, which hails from South Africa. Botanists consider the gladioli to actually be corms, not true bulbs. Corms are underground plant stems that function as storage organs, whereas true bulbs are underground storage organs made up of layers of fleshy modified leaves. Most gladioli are hardy only to zone 8, which makes them annuals in Colorado. But there are some gladioli that are hardy to zone 5, if well mulched in winter. Gladioli come in many colors and sport bright blooms on upright stems with strap-like leaves.
Like the “glads”, dahlias are another very popular summer bloom that is not hardy in Colorado. Dahlias are placed in the spring planted bulb category because they form tuberous roots which are dried and then sold. The pre-cultivar dahlias are native to Mexico. There tubers were used as a food crop by the Aztecs. The trick to buying dahlias in dry form is that they must have a stem attached to the tubers, because only the stems produce buds, which then produce stems and flowers. There is a huge variety of dahlia cultivars to be found in garden centers. In springtime, the dahlia tubers are sold in bags along with the other spring planted bulbs. But in summer it is common to see the dahlias sold as potted plants. Buying them as tubers is cheaper than as potted plants. Because the dahlias are hardy only to zone 8, if you want them to return to your yard next summer you must save the tubers (with a bit of the stems attached) Â in a cool but not freezing space, to be replanted in a successive season. Or simply just buy new ones each spring. Dahlias are popular because the blooms come in a multitude of shapes, colors and sizes. If you’ve never seen a 12 inch wide “dinner plate” dahlia flower in bloom, you are missing out on a fascinating sight.
Canna Lilies are another spring planted “bulb” that bring an air of the tropics to your landscape. These flowering plants are often used in annual pots, providing tall, colorful focal points in the center surrounded by lower annuals. Cannas are native to Latin America and are grown as annuals in Denver’s hardiness zone of 5. But if you find the right micro-climate, they may over-winter just fine. I know of one house in Denver, where cannas are planted at the base of a south facing wall on a house, and have become perennial in this residential landscape due to this warm micro-climate spot. Cannas are not true bulbs, but are “rhizomatous.” A rhizome is an underground horizontal stem that can send out shoots and roots from nodes. A ginger “root” is an example of a rhizome that you’ll find in a produce section. Cannas are closely related to ginger and also bananas! Another familiar rhizomatous plant are irises, which have above ground rhizomes. Although canna lilies are often available as potted plants throughout summer, if you purchase them as rhizomes in spring, you get the plants for a fraction of the cost of potted ones. As mentioned previously, cannas develop tropical-like flowers and leaves, giving your patio an island vibe.
Canna rhizomes.
Head on down to your local garden center this spring gardening season and pick up some spring planted bulbs to brighten your landscape this summer!
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
