As landscape architects, we know that color is more than a visual detail—it’s a key part of how a space feels and functions. Color has the power to transform any outdoor space, setting the mood, highlighting focal points, and bringing fresh interest through every season. With a few strategic choices, you too can use color to add personality and life to your landscape.
Hues That Evoke Emotion
Colors in your outdoor space can set the tone and affect your mood. Cool tones like blues and purples are known for their calming effects. You can introduce these colors with flowers like veronica, phlox, lilac, or even boulder blue fescue. Water features, outdoor furniture, cool-toned metal, or stone elements can also draw on these cooler hues to help create a soothing atmosphere.
On the flip side, warm colors—reds, yellows, and oranges—inject energy into a space. Plants like red twig dogwood, barberry, and blanket flower can add vibrancy, while colorful art sculptures, fire pits, or natural wood accents warm up the space. Whether you’re aiming for relaxation or excitement, colors help set the mood.
Individual style typically involves combining colors to balance the mood. Blending a variety of colors in a garden can create a whimsical, playful atmosphere. This approach adds energy and unpredictability to a space, making it feel lively and dynamic. On the other hand, a monochromatic palette, such as using shades of white, silver, or any single hue, lends a sense of sophistication and elegance to the landscape. A unified color scheme creates harmony, making the space feel more refined and cohesive, perfect for formal gardens or modern minimalist designs.
Seasonal Color Variations for Year-Round Interest
A well-designed landscape can feature color year-round by selecting plants with different seasonal traits. In the spring, bring in early bloomers like tulips, daffodils, or forsythia to brighten things up. Summer brings a wave of colorful foliage and blooms, while autumn offers the brilliant reds and yellows of trees like maple, aspen, and sumac. Even winter can shine with evergreen plants, striking bark, and the silvery dried plumes of ornamental grasses.
You can also use annual flowers for even more seasonal flexibility. Swap them out every season or year to add fresh colors without long-term commitment, allowing your landscape to constantly evolve.
Creating Focal Points in Your Landscape
Colors can be used strategically to direct attention. A vibrant flowering tree, a bold garden sculpture, or a brightly colored planter can serve as a focal point, guiding the eye and adding interest to a specific area.
Creating contrast also brings depth to your landscape. For instance, pairing burgundy coral bells with chartreuse sedge or placing bright white flowers against a deep green backdrop can create dramatic, high-impact visual effects that draw attention and keep your design lively.
Environmental Impacts of Color Choices
Color affects more than just the aesthetics of your landscape; it also has environmental impacts. Lighter colors reflect heat, making your outdoor spaces cooler and more comfortable, while darker features like pathways or furniture absorb heat, influencing plant health and the comfort of those using the space.
Color can also attract beneficial pollinators. Bees, butterflies, and birds are drawn to shades of purple, yellow, and red, making thoughtful plant selection not just about beauty but also about supporting the local ecosystem.
In landscape design, color plays a vital role that goes beyond mere aesthetics. It shapes the atmosphere of your outdoor space, offers seasonal variety, and can even impact the surrounding environment. Whether you desire a serene retreat or a lively garden, thoughtful color choices can dramatically enhance how a landscape is perceived and enjoyed. By selecting the right plants, materials, and design elements, you can create an outdoor oasis that beautifully reflects your style and harmonizes with nature.
If you’re ready to bring more color, energy, and visual interest to your outdoor space, the team at Outdoor Design Group can help. Our experts specialize in crafting beautiful, functional landscapes that reflect your vision and enhance your environment.
Imagine a shade tree that’s free, never needs water and will never die. Too good to be true? Yes, it is.
This is known as The Tree of Heaven (Ailanthus altissima) and it’s a widely distributed noxious weed. The ensuing text presents five noteworthy noxious weeds growing on Colorado’s Front Range. As evident with these five weeds, the public attitude towards weed management must evolve to reflect the staggering reality at hand – invasive plants have spread globally and some of these plants have very particular adaptations that are highly detrimental to native ecosystems, naturalized ecosystems and (even) human health. Landscape architects, property owners and the public must respect noxious weed classifications in order to confront the problem.
Bindweed in a recently installed commercial landscape. Westminster, CO. Credit in work cited (photo 1)
What’s a weed? The simple answer is that one man’s weed is another man’s treasure. This topic is stacked with semantic complexities. The term ‘weed’ is used to subjectively describe undesirable plants. This definition is flimsy – like a plastic bag blowing in the wind. An ecological interpretation contends that most weeds are ruderal species, which appear in high-productivity environments with high levels of disturbance (Beck, 2013). They pop up when conditions allow & devote all energy to seed production. These plants colonize disturbed land & are eventually overtaken by larger species. Weeds that mature into shrub or tree form are merely invasive. Invasive plants are introduced into an environment where they did not evolve. They are highly successful, to the point where they outcompete native plants. In other words, they found a new home with similar conditions to their old home. Invasive plants range from ruderal weeds to large shade trees and they are highly influenced by location & climate. What’s invasive in California will probably not be invasive in New Hampshire, though some noxious weeds are adaptable enough to span vast geographic regions. ‘Noxious weed’ is a legal term that cuts through layers of ambiguity. If it’s a noxious weed, then, yes, it’s a weed – and you should eradicate it! The State of Colorado considers noxious weeds to be:
Aggressive invaders that are detrimental to the economy & native ecosystems.
Plants that can poison livestock.
Carriers of detrimental insects, diseases & parasites.
Plants that are detrimental to the sound management of natural or agricultural ecosystems.
The spread of plant material by sea-faring Europeans during the 18th century was a landmark shift in global ecology. Previously, plant populations were very localized. Now days, mass disturbance and plant migration have imperiled native ecosystems – as demonstrated by the flowing weeds, which are all non-native, invasive & noxious But first, a few mentions are in order.
Noxious weeds are classified by the government as a matter of policy.
They are classified as type A, B, C, with A being the most harmful.
Noxious weed management requires specialized knowledge and techniques.
Noxious weeds are highly adaptable and competitive due to adaptations picked up from their native habitat over thousands of years.
They lack natural controls from their native habitats (insects, pathogens, etc.).
Noxious plants come in all forms: annual, perennial, vine, shrub & tree.
The remedy for non-noxious weeds is a non-lazy individual with two hands, two feet & the ability to visually differentiate.
Most non-noxious weeds DO NOT require an herbicide! Just pull them before they flower.
Type A noxious weeds are designated for eradication by the Colorado Department of Agriculture (CO DOA, 2024). These next level super weeds include Japanese Knotweed (Reynoutria japonica) – one of the most invasive plants in the world. It was taken from the slopes of a Japanese volcano and brought to Europe during the mid-1800s. It has spread worldwide and has been found in at least 12 Colorado counties. The plant is so prolific that it can grow through asphalt and even into buildings. Why? Because it adapted to the extreme conditions of its natural environment – volcanic islands. It has adapted to massive disturbance and is the first plant to recolonize the volcanic moonscape post-eruption! If you have this plant.. refer to expert advice for removal. Godspeed!
(Left, 2) Japanese Knotweed in its native habitat and (right, 3) its new habitat. Photo credits in work cited (photos 2 + 3).
Type B weeds are included in Colorado Department of Agriculture noxious weed management plans – which intend to eradicate/contain/suppress their continued spread. Russian Olive (Elaeagnus angustifolia) illustrates this category in Colorado. Like other invasive plants, it was installed with legitimate intentions, windbreaks in this case, but it quickly became detrimental to the native environment. Often found in riparian zones up to 8000’, Russian Olive is highly adaptable – it is tolerant of shade and poor soil. In Colorado, they stress native riparian zones, outcompeting cottonwoods and willows (CO DOA, 2014).
Type C weeds are included in state noxious weed management plans, but their elimination is not a goal. Instead, outreach and education are program goals. Prolific urban weeds in our region are typically Type C and include the Tree of Heaven, Field Bindweed and Poison Hemlock – among others. These plants are widespread and their complete elimination is impossible. If you live in the Denver metro area, you have seen them. The Tree of Heaven (Ailanthus altissima) is the quintessential urban trash-tree. Originally from China, this highly adaptable tree can grow 9 feet in a single growing season up to mature heights of 40-50’. If cut, the tree responds with a myriad of suckers (cut off one head and five grow back). It unsurprisingly produces thousands of seeds and also spreads by rhizome. It can be eliminated with the application of glyphosate to a freshly cut stump. Another worthy mention goes to European Field Bindweed (Convolvulus arvensis) – the ultimate yard pest. It is thought to have originated as an imported seed contaminant (NPS, 2009). Also known as morning glory, it is highly adaptable and aggressive. It’s ubiquitous white flowers can be found growing within your bluegrass lawn, flower beds and anywhere else with soil, light and water. It’s a perennial vine that reproduces via seed and creeping roots (NPS, 2009). Much like the Tree of Heaven, Bindweed does not like glyphosate and 2-4-D, but this method only works while the plant is actively growing. Best of luck getting rid of this one.. The final type C noxious weed killed Socrates and is known as Poison Hemlock (Conium maculatum). It’s highly adaptable, but prefers riparian areas, producing thousands of seeds from white flowers. There’s enough coniine within 6-8 leaves to invoke respiratory paralysis and death (USDA, 2018). Other mammals are also at-risk including canines and livestock. On the Front Range, it is found in thick stands with carrot-like leaves and white flowers. It can be eliminated by chemical and mechanical means. Be sure to wear PPE if interacting with this plant! It is highly toxic!
Tree of Heaven stand. Photo credit in work cited (photo 4).
So, what do we do about it? The prevention of noxious weeds by homeowners and commercial property managers requires knowledge and effort. If the government considers a plant noxious, it should be eradicated before it flowers and disperses 180,000 seeds that last for 100 years (Mullein!). It doesn’t matter how pretty you think it is. Weeds, regardless of their classification, thrive with neglect. At the most basic level, human development is disturbance and disturbance generates weeds. Limit disturbance as much as possible and preserve native habitats. Be careful with imported fill; it might be stacked with weed seeds! Pay attention and guide your landscape in the right direction. Learn how to eradicate these plants. It’s not as simple as you might think. Many of these plants have extensive root systems that will reshoot in perpetuity. Herbicides are massively overused, yet they are an extremely useful tool in this fight. Use them sparingly and safely! We’ve significantly altered the earth and it’s our responsibility to mitigate the damage! At the end of the day, just be glad you don’t have Japanese Knotweed growing through your floorboards.
Landscape architects (LAs) are part of the problem and the solution. LAs manage a larger scope than just plants, but typically develop plans to replace existing vegetation with proposed vegetation in accordance with code, client, budget, site, etc. Intentions are benevolent, yet ideas turn into plans, which turn into commercial shopping centers, homes, parks and so on. Landscape architects, in a sense, perpetuate ecological disturbance, opening the door for colonizer species (aka: Weeds). Of course there’s a plan to avoid this, which is one reason landscape architecture exists in the first place. It’s critical for LAs to identify existing noxious weeds on a project – so they can be eliminated before breaking ground. Many noxious weeds have deep roots, allowing them to survive extreme disturbance (like a construction project). Landscape Architects employ a myriad of techniques to manage plant competition and succession. They are highly trained individuals, but more can be done. They can advocate for limited disturbance to native landscapes. They can design native landscape zones on the site periphery. They can stipulate proper maintenance for native grass. With landscape architecture, this goes beyond noxious weeds. Are business incentives and ecological stewardship mutually exclusive?
* This was not written by an ecologist, policy maker or certified pesticide applicator. Nor was it written by an official landscape architect. Seek expert advice elsewhere before making any drastic decisions! Your local CSU Extension Office is a good place to start.
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.
Outdoor Design Group is based in Arvada, Colorado – this blog concerns the Great Plains and Western United States. A previous blog post – wonderfully written by Julie O’Brien – traced the origins of the “green carpet”. The ubiquitous American lawn. It’s important to note that the green carpet exists in multiple forms. It’s a literal thing and a cultural construct. Most Americans associate homes with green lawns regardless of the prevailing environmental conditions. The lower 48 of the USA receives between 5” – 120” annual precipitation. Established Kentucky Bluegrass (KBG) requires about 26” of precipitation during the growing season. Our collective perception of the green carpet must incorporate prevailing environmental conditions!
Within the confines of this blog, the term ‘native grass’ refers to grass species found on the Great Plains prior to western settlement; to understand the applicability of native grass, refer to the map below. The eastern half of the United States receives 30 – 70” per year; the western half gets 5-30” (with exceptions in the Pacific NW). Denver sits on the dry half with 15” annual precipitation. Landscape is all about place, and our place is pretty dry. Our native flora have adapted to the prevailing conditions, yet the same cannot be said for the green carpet!
Sown native grass shines in low-traffic applications. Once established, it needs no supplemental water or fertilizer. It is not soft and fluffy. It needs full sun and doesn’t tolerate heavy foot traffic. If planted in your front yard, there is a high probability that at least one neighbor will vehemently dislike. Yet it’s a solid solution for covering low-use space. After all, you need to do something with any given patch of earth – so weeds don’t run amok. Semi-arid climates such as ours render large-scale KBG nonsensical. It requires excessive irrigation, fertilizer and herbicides, while contributing zero ecological value. Native grass isn’t a silver-bullet; it’s a tool in the toolbox that’s applicable to many areas.
There are myriad factors to consider with native grass. First off, it doesn’t have to be native! Secondly, many species are sold by container. While many viable grass species are endemic to the Great Plains, other well-adapted varieties come from elsewhere in the world. Either way, native grass species have deep roots, grow relatively tall and are not available as rolled sod. They are typically sown by seed, and in some cases installed by plug. It’s difficult to establish and there’s an ongoing maintenance requirement. Ample moisture is required during the first season and an underground sprinkler system is recommended. Temporary (above ground) irrigation can also be used. Weed management is critical. Certain weeds (especially bindweed) must be addressed BEFORE installation! Ongoing weed management will be required! Native grass is not easy. If you’re willing and able, you’ll be rewarded.
There are many cool & warm season grasses to choose from – that differ in terms of height, texture & cold-tolerance. On the shorter side, buffalograss and blue grama are proven options. Taller options include little bluestem, big bluestem, switchgrass, western wheatgrass, sideoats grama & tufted hairgrass – in addition to many more. You might consider several varieties of water-thrifty turf as an alternative to native grass. Options such as Dog Tuff, RTF Tall Fescue & Tahoma 31 Bermudagrass.
This is not an installation guide. Contact your local agricultural extension for more information. Seed suppliers such as Pawnee Buttes and Arkansas Valley Seed are also great resources. Most western residential and commercial landscapes have a place for KBG – the key is scale; not overdoing it. Native grass isn’t for everyone, nor is it perfect for every landscape – yet it’s severely underutilized!
Written by Matthew Whiteman
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.
