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.
Lately, it seems there has been an ever-growing buzz in the media regarding native plants. We here at Outdoor Design Group appreciate this budding interest in native plants, but we have a long-established love and interest in utilizing native plants in the landscapes we design.
The blooming enthusiasm for North American, as well as regionally specific native plants got us thinking about how to advise native plant newbies to get started with these plants in their gardens and landscapes.
If you’re not sure why you should include native plants in your Colorado landscape (or any landscape anywhere on earth for that matter), here are a few reasons:
They’re adapted to the water, light, soil and temperature fluctuations and constraints of your area.
They’re adapted to the animals and insects of your region, providing food & shelter for the native fauna, as well as being generally more resistant to browsing by insects and other animals.
Utilizing them in your landscape design helps anchor your property in the ‘place’ of your region. Put another way: Why grow plants that can be grown in New York, London or Tokyo? Why not grow plants that show your interest and love of the region you live in?
This brings us to a quick list of the 14 Easiest Colorado Native Plants to include in your landscape.
Before we get to the list, we must mention one big caveat: the term “native” plant is somewhat subjective. What area is one referring to when they say, “native to a certain region”? North America? The Great Plains? The Rocky Mountains? The state of Colorado? Only within a 50-mile radius of your location? The native plants we are presenting on the following list are mostly native to the Rocky Mountain region, while some on the list are more broadly native to North America.
The other thing we should mention is that while native plants have various and obvious good reasons to be utilized in one’s landscape, there are many non-native plants that can be good and ecologically appropriate choices for a certain landscape as well.
It’s worth mentioning that even if a plant is native to your region or state, that doesn’t mean that these plants will do well in every situation your yard presents. For example, aspen trees are native to the state of Colorado and surrounding Rocky Mountain states, but only are they native to the mountains and foothills. Aspen trees often struggle on the hotter drier front range cities east of the mountains where Denver is located. And just because a plant is a “native” does not mean that it won’t perform like an invasive weed. An example of this is Virginia Creeper (Parthenocissus quinquefolia) which is a North American native vine but reseeds readily in many areas and can be difficult to remove.
It all depends on many factors! Now, on to our list of great native plants to grow in Colorado:
TREES:
– Blue Spruce (Picea pungens). Sporting a conical and classic Christmas Tree form, this evergreen tree has moderate water needs so should be thoughtfully placed if your property is hotter & drier. There are many cultivars to choose from. This is one evergreen tree that might do better in an irrigated lawn.
-Bristlecone Pine (Pinus Aristata). This is a tough pine tree that is native to higher elevations but can do well in some locations at lower elevations. It can have an irregular and shrubby form. Like most pines, it has low water requirements.
Bristle Cone Pine
-Pinon Pine (Pinus edulis). The native range of this pine is generally southern Rocky Mountains of Colorado and New Mexico. This is a good pine tree for hotter and drier locations. Its form is somewhat bushy and rounded. And the nuts are edible!
-Cottonwood (Populus spp.). There are several types of cottonwoods to choose from. They are all tough and dependable, but they don’t live very long. And some varieties have a suckering habit. They prefer moist soils, and they grow fast. They can be messy as well, so best for informal areas or larger properties.
-Bigtooth Maple (Acer grandidentatum). One of the few maples that can survive drought type conditions. Related to sugar maples, this native of the Rocky Mountain region has orange-red fall color and is more adapted to Colorado’s alkaline soils so it shouldn’t suffer chlorosis like other maple trees. This tree maxes out at 20-30 ft. tall and is more shrub-like (with multiple stems) and not a classic shade tree shape like some more popular and common (but not suited for Colorado soils) maple trees sold in local nurseries.
Bigtooth Maple, fall color
SHRUBS:
-Currants (Ribes spp.). There are several native varieties of currants to choose from. One of our favorites is Crandall Clove Currant, Ribes odoratum ‘Crandall’
-Yucca (Yucca spp.). Yuccas are tough plants that are well adapted to most areas of Colorado and the surrounding states. Some species and varieties are less cold hardy than others. If you’re bored with the local native Soapweed Yucca, you could try Banana Yucca, Beaked Yucca or even Dollhouse Yucca. If you’re worried about the stiff spiky leaves, you could opt for Yucca filamentosa, which has spiky tips, but the leaves are less stiff. It is native to the Southeastern United States, so they’re less drought tolerant than other yuccas.
Adam’s Needle Yucca
-Agave (Agave spp.). Agaves bring stunning architectural interest to the garden with their sword-like leaves. Most agaves that are native to North America are not cold tolerant enough to be grown in Colorado, but there are at least 3 species that can handle winter in greater Denver and other Front Range areas, as well as The Grand Valley on the Western Slope. Any areas that are at least USDA zone 5 or higher. As with cacti, keeping the agave roots on the dry side during winter will help them survive the cold. One of the cold hardiest Agaves is the Harvard’s Agave, Agave havardiana.
-Opuntia Cacti (Opuntia spp.). If you can get past the spines, you will be rewarded with amazing flowers in late spring. Not every Opuntia cacti variety is cold hardy enough for all of Colorado. But a few varieties are hardy to zone 5 and are great additions to your xeriscape, providing a stunning floral display in spring and interesting shapes and forms all year round. And if the spines are a roadblock to enjoying these North American natives, there are some cultivars with less spines. Cacti will be happier if their roots can be in mostly dry and well-drained soil throughout the winter.
Opuntia, Chocolate Princess cultivar
Perennials & Ornamental Grasses:
– Native Blanket Flower (Gaillardia aristata). Blanket Flower is a wonderful North American native flower that provides eye-popping yellow, orange and red color when it blooms in late summer to early fall.
– Penstemon (Penstemon spp.). There are so many Penstemon cultivars and nativars to choose from, its hard to pick just one. Some live longer than others. Two of our favorite penstemons (how can we pick just 2?!?) are Penstemon pseudospectabilis, and Penstemon pinifolius.
Pineleaf Penstemon
– Desert Four-O’-Clock (Mirabilis multiflora). The Desert Four-o-clock is a low-growing perennial that is very drought tolerant. It grows and spreads fast during summer with a display of bright magenta-pink blooms, but it is an herbaceous perennial, so it “dies” back to the ground every fall, like peonies.
– Columbine (Aquilegia spp.). A classic perennial plant with many varieties to choose from. These plants generally do better in cooler & wetter conditions. It’s best to save them for the part sun / part shade areas of your property.
– Blonde Ambition Grama Grass (Bouteloua gracillis ‘Blonde Ambition’). This nativar, discovered by the late David Salman of High Country Gardens, has exploded in popularity, almost to the point of being overplanted. But it’s popular for good reasons. It is tough, drought tolerant and visually striking in the fall when it sends out its one-sided seed heads that catch the sunlight in the waning days of autumn.
Blonde Ambition Grass
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.
Today’s photo is a recent view of a portion of one street median renovation we designed in Lakewood Colorado. We designed several landscape plans for this renovation project, consisting of many miles of existing street medians in that city, that are slated for renewal. It was an interesting and challenging project to work on, and the city staff were great to work with. We look forward to seeing how these designs grow and flourish over time!
Landscape median in Lakewood, Colorado
Before renovation photo of the same median as above, but with camera looking north.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
