by Todd Rutherford
A few months ago, on a trip through New Mexico, I stopped by Ghost Ranch for a short visit and hike. Ghost Ranch is a beautiful area in north central New Mexico. It is a retreat and education center that belongs to the Presbyterian Church, but is open to the general public (all visitors must register with the visitor center). Though there is a long history to the Ranch, perhaps it has become most well known due to its links with the artist Georgia O’Keeffe, who once owned a home on a small portion of the Ranch.
Near the Ghost Ranch Visitors Center.
Chimney Rock
There is an easy and rather popular hike to a rock formation called Chimney Rock, not far from the Ghost Ranch Welcome Center. As I ambled along the trail to Chimney Rock on that cool and windy Spring day, I was delighted to come across what I believe to be Yucca harrimaniae, occasionally dotting the sides of the trail. This small and very charming yucca was quite numerous on areas along the hike.
Cluster of Yucca harrimaniae (or are they Yucca angustissima?)
In the limited research I did, I discovered that there is also a possibility that the yuccas I saw at Ghost Ranch might also be Yucca angustissima. And it seems that there is disagreement among botanist about these two species of Yucca, and what distinguishes them. For the sake of simplicity, and at the risk of being wrong, I will refer to these yuccas as Yucca harrimaniae. Some people call Yucca harrimaniae by the common name Harriman’s Narrow Leaf Yucca.
I have seen these in the Denver area, planted in gardens, but I had never before noticed them in the wild, as I am usually accustomed to only seeing Yucca glauca, which is quite common in natural areas of northern and eastern Colorado. That is why I was so excited to see them. The Yucca harrimaniae leaf color is less blue-grey than Yucca glauca (glauca or glaucous translates to “blue-grey” in Latin), and I think Y. harrimaniae exhibits more of the curly white “side hairs” than the Y. glauca. Like all other yuccas, these will sport a beautiful flower stalk in spring to early summer.
My 11″ shoe as a size comparison.
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by Todd Rutherford
As Denver slips into a typical high plains spring weather pattern of sloppy snow storms interspersed with breezy sunshiny days, I wanted to share these recent photos of a magnificent magnolia at the Denver Botanic Gardens. This particular variety of magnolia packs a double punch of gorgeous silky blooms, which also emit an intoxicating scent. I’d describe the scent as a mixture of citrus and rose. Amazing!
This particular magnolia is called a Yulan or Jade Lily magnolia (scientific name: Magnolia denudata). It is native to China, and has been grown in Chinese Buddhist temples for more than a thousand years. The Magnolia is an ancient genus, appearing before bees did. Botanists have theorized that magnolias evolved with beetles as their main pollinators.
I’m enjoying these pictures as the rain is slowly turning to snow outside my window, with the thought that those wonderful magnolia flowers may perish if the snow gets too heavy or if the temperature drops much below freezing. Perhaps their fleeting nature makes these magnolia flowers all the more beautiful.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
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) 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.
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by Todd Rutherford
Located in Littleton, Colorado, The Gardens at Columbine is a memory care/assisted living facility on which Outdoor Design Group provided landscape design services. This site was an expansion of an existing assisted living facility onto adjacent property. This new building provides a space for adding memory care services to the facility’s roster of other existing services for senior citizens.
As the new building was being planned for this recently acquired property, we designed the outdoor spaces, walkways and landscaped gardens to surround this new structure. Because the site was not terribly large, and the proposed building sizable in scope, this provided several challenges. From how to fit parking spaces into a small space to designing safe and sound emergency exit pathways, this project was a challenging but satisfying endeavor.
One of the first challenges we had to face was how to provide a working landscape at the east entrance to the building. This entrance is near the other existing building, and is the preferred access point for employees traveling between buildings. The difficulty here was adding an entrance walkway that would transition from a higher elevation parking lot then drop down to a doorway that sits slightly below grade relative to the parking lot. Retaining walls were necessary in this area so we added built in benches at the walls to provide useful amenities along this path. Step lights in the walls provide a soft illumination for this well used pathway.
Prior to construction, the original site was filled with trees, as it had been a large lot with one single family home on it. While some of the existing trees could not be saved due to the scope of the proposed building, we worked with the city and the owner to save as many trees as we could. For example we spent a significant time working and re-working the landscape plan with the civil engineer on the project to reconfigure the entrance drive and parking areas to save several existing trees on the north and east sides of the property.
The namesake gardens are located in the internal courtyard of the project. These outdoor spaces give residents of the facility a charming scene that invites them to go outside and get some fresh air amid the trees, shrubs and raised bed gardens.
Stepping out of the building and into the courtyard, the first of the raised planting beds one encounters is a large circle comprised of a poured-in-place concrete seat wall that is chock full of colorful perennials, wispy ornamental grasses, low growing shrubs and scraggy boulders.
As you step further into the courtyard, you encounter wooden raised bed gardens where residents of the facility can indulge their gardening bug and get their hands dirty in the soil. These two beds are situated on opposite sides of the courtyard, connected by a concrete walk where the residents can circumnavigate to achieve fresh air and exercise, ensconced in the protective calm of these hidden gardens.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
A visit to the Denver Botanic Gardens has revealed that the first signs of spring are making their presence known. As we have been experiencing a recent warm spell here in the Denver area, I decided to check out the Gardens to see what might be blooming. Sure enough, there were many bulbs and some shrubs that were taking advantage of the balmy weather to burst forth in bloom.
Below are just a small sampling of what’s flowering now at the Gardens:
Clockwise from left: Witchhazel; Snowdrops; Hellebores
Clockwise from left: Dwarf Iris in Partridge Feather; Dwarf Iris with Crocus and Agave; Winter Aconite
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
When it comes to trees in designed landscapes in Colorado, landscape architects and designers don’t have very many species to choose from. With that being said, it might seem heretical to propose that the list of trees to pick from be restricted even further. Specifically, I advocate that large evergreen trees NOT be planted in dense urban areas that experience cold winters, unless they are sufficiently distant from walks and streets located north of such evergreens.
The shadows that large evergreen trees cast can help foster ice patches on walks and roads, compromising the safety and welfare of those who utilize these areas to travel about our towns and cities. If we are going to encourage biking and walking to ease automobile congestion and alleviate environmental impacts, having the safest travel routes we can achieve is a noble goal.
It may be surprising to those who don’t work in the landscape, architecture or planning fields, but many municipalities require that a certain number or percentage of the trees on a landscape plan be evergreen trees. Sometimes these arbitrary requirements restrict designers and architects to squeeze these large winter-shading ice patch-makers into a site where it might be best to avoid them. However, I should mention that some municipalities that I’ve worked with do acknowledge the problem of winter shading from evergreen trees, and they do have instructions in their landscape codes to locate proposed large evergreens away from walks and roads that would be shaded by those evergreens.
I first became aware of the problem of evergreen shadow ice patches as an urban bike commuter in the Denver area. It is frustrating at best, and rather dangerous at worst to encounter a patch of ice on a street during winter time. I have found that often times when biking in the Denver area in winter, the majority of streets can be clear of ice, except for those areas shaded by evergreens that are located just south of walks and streets. But it is not just bikers that would benefit from restricting evergreen trees in urban areas. Walkers and runners would also have an improved level of travel safety due to less icing of their pathways.
An ice patch on a Denver street, from the shadow of a large evergreen tree.
Because the foliage canopy of pine, spruce and fir trees does not drop during winter, melting of snow and ice via solar gain is limited. Deciduous trees, which drop their leaves and allow more sunlight to reach walks and streets, are a better choice in place of evergreens. I acknowledge that evergreen trees are often used for landscape screening. But I question whether this screening is worth it when considering their impact to roads and walks during winter.
Another impact from lost solar gain due to evergreen tree shading is on homes and other buildings. A building that sits in the winter shadow of a large evergreen tree will miss out on solar warmth during a sunny Colorado winter day.
I do realize that in dense urban areas, it’s not just trees that can shade our streets and sidewalks. People need shelter and workspaces, and some of those structures could end up shading streets and cause ice patches. But residents don’t need evergreen trees on their urban lot. I advocate for trees to create shade in summer, visual interest in all seasons, and wildlife habitat. But the choice of tree in tight urban quarters needs to be considered carefully.
Despite the tongue in cheek title of this blog post, evergreen trees can be a wonderful addition to the landscape. I am not actually asking for evergreen trees to be banned from urban areas of Colorado. However it does seem best that in dense urban areas that experience cold winter weather, we should consider restricting evergreen trees to parks and large lots, away from streets and sidewalks where their winter shade will not cause icy travel dangers for walkers, bikers and even cars.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
Calamagrostis brachytricha, Korean Feather Reed Grass
Calamagrostis brachytricha, aka Korean Feather Reed Grass, is a clump-forming ornamental grass with green leaves and fluffy flower plumes. It is not as well known as its infamous cousin Calmagrostis acutiflora ‘Karl Foerster’, commonly known as Karl Foerster Feather Reed Grass. But Korean Feather Reed Grass really should get more attention, as it is an indispensable option to add wispy texture to planting schemes in part shade conditions.
PLANT STATS
Scientific Name: Calamagrostis brachytricha
Common Name: Korean Feather Reed Grass
Plant Type: Ornamental Grass
Mature Height: 3-4’
Mature Spread: 2-3’
Cold Hardiness Zone: USDA zones 4 – 9 (up to 6,500 ft)
Water Requirement: Medium. Slightly drought tolerant once established, but prefers adequate moisture. Requires regular amounts of water if it is planted in more sun.
Exposure: Part Sun/Shade
Soil: Tolerant of a wide range of soils.
Flower Color & Bloom Time: The feather like flower spikes have a pink tinge when they initially emerge in late summer, and then fade to straw yellow in fall. Compared to Karl Foerster grass, the flowers of Korean Feather seem to be much more misty and gauzy when they first appear which gives the plants a wonderfully diaphanous appearance.
Winter Interest: Gold foliage and flowers.
Disadvantages: May reseed under certain conditions.
Availability and Sizes: This plant seems to be regularly available at retail nurseries around the front range. It is typically sold in 1 gallon or 4″ pots.
Best Features: A large, showy, flowering ornamental grass that can take shady conditions.
Maintenance Tip: Like other ornamental grasses, trim plants down to about 4-6” above the surrounding soil in late winter or early spring, before new growth begins to emerge.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Matt Corrion
The landscape design includes patio space and a gas fire pit that allows easy enjoyment of the mountain views
Are you considering purchasing a new home? When you tour the lot, examine the adjacent views and how the site may be landscaped and used for outdoor living space. With a little foresight and a good design, the yard can be made into an inviting extension of your home for your family and guests alike.
For this project, located on the west side of Arvada, Colorado, we worked with the homeowners to take advantage of amazing mountain views, while adding value and convenience to their property. A sloped lot was redesigned to provide a flat lawn area and a secondary seating area with a custom gas fire pit. Pavers were used to soften the existing covered concrete patio, and a built-in outdoor kitchen and bar seating were added. Soft lighting provides security and ambiance in the evening, while the Rocky Mountains provide the backdrop for stunning sunsets.
The view from the back of the lot toward the house and outdoor kitchen
View of firepit with tiered lawn behind
The view from the leveled-off lawn are to the outdoor kitchen
The existing sloped backyard
Most builders will include a basic front yard landscape in the home price, but will leave the back yard as bare ground for you to improve however you wish. The design must be approved by the homeowners association. The proposed landscape will need to ensure proper drainage and shouldn’t have any negative impacts on your neighbors lots, or adjacent open space.
The front yard can always be redesigned as well. The front yard irrigation mainline and valves should already be in place, so the design can be modified pretty easily. This homeowner asked us to redesign the front yard simultaneously, and they plan to redo the front yard in a second phase. For the time being, they have completed their landscape, eliminating the bare dirt and allowing them to fully enjoy their new home and yard.
Pavers were installed over the concrete patio that came with the home
Enjoying a beer and the mountain views
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
As we move further into the fall season, many gardeners have turned their attention to cleaning up and preparing to put their gardens to bed for winter. Gardeners should also take this time to plan ahead for spring blooming bulbs which are currently available in your local garden center. Now is the perfect time to add these must-have jewels to your landscape. For most areas in Colorado, you should plant these bulbs sometime between the middle of September to the end of October. I have planted bulbs as late as November during a mild fall and winter. As long as the ground is not frozen, you can plant bulbs. However, by planting in early fall you give the bulbs time to establish some roots before the soil freezes, ensuring the best success. Lucky for us, the growing conditions in much of Colorado are perfect for spring blooming bulbs. The climate and ecological conditions of many of the bulb’s native ranges are quite similar to our high plains region.
Crocus popping up through veronica and sedums.
The diversity of size, shape and color of spring blooming bulbs is fascinating. Some of the best bulbs to plant in our area are (listed in order of bloom time) :
Early Spring Bloomers: crocus, Siberian squill, snowdrops, dwarf iris, and species tulips
Mid-Spring Bloomers: hyacinths, daffodils, grape muscari, fritillaria and tulips
Late Spring Bloomers: alliums, irises and fox-tail lillies
Alliums with Cholla cactus.
Fall planted bulbs do best in soils that are well drained. If the soil is too wet, the bulbs may rot. The rule of thumb is to plant the bulbs at a depth 3 to 4 times the length of the bulbs. If you buy bulbs in a package, a visual guide to bulb planting depth is usually printed on the package.
Consider adding “bulb food” to the holes you’ve dug before you drop in the bulbs. Phosphorus fertilizer will give your bulbs a boost, and help them become established. Traditionally a product called “bone meal” was recommended for providing phosphorus to bulbs. But research done at Colorado State University has shown that product doesn’t work well in our typically alkaline soil chemistry. Consider a conventional (a.k.a. “non-organic”) fertilizer called “triple super phosphate”. However, using phosphorus from conventional fertilizers has been linked to environmental damage such as toxic algae blooms in lakes and rivers. Use the conventional phosphorus sparingly and carefully. If you’ve not already done so, amending your soil with compost is also a good idea to improve soil texture for your bulbs.
Close up of foxtail lillies.
Most spring blooming bulbs do best in full sun to part sun locations as opposed to deep shade. But if the site is south facing in full sun, that area’s soil may warm up too much in late winter, causing the bulbs to flower early and those blooms would be susceptible to frost damage during cold snaps. It is a good idea to mulch the soil where you’ve planted the bulbs. Mulch will keep the soil from drying out, and help moderate soil temperature so it doesn’t warm up too quickly.
Design-wise, you can tuck just a few bulbs into niches between established perennials and ornamental grasses in your garden, or you could add large groupings of one type of bulb to get maximum color punch in your landscape. One effective way to add bulbs to an existing garden is to place them around low-growing plants that will still be dormant when the spring bulbs emerge. That approach is particularly effective with low growing groundcover perennials. Some people will add early spring bulbs such as crocus or snowdrops to a lawn area, knowing that the grass won’t start growing or need a mowing until after the bulbs are done. And if you want to add bulbs year after year, you might want to make a plan or take photos of where the existing bulbs are when they are blooming. That way you can avoid disturbing the established bulbs next time you add more in the fall.
Tulips mingling with veronica and the remnants of last year’s ornamental grass.
For all the bulbs, you should not remove the leaves after the flowers have faded, until the leaves have turned from green to brown. Removing green leaves too early deprives the bulbs the ability to feed themselves in preparation for the next year’s blooms.
If your bulbs are “happy” where you’ve placed them, there’s a chance they will supply you with gorgeous blooms for many years. Adding spring blooming bulbs to your garden is an easy way to get dependable spots of color into your landscape for a springtime show!
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
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by Todd Rutherford
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.
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