by Matt Corrion
By now most people in the western U.S. are familiar enough with Xeriscape to know that there is indeed no “zero” in the pronunciation (it’s pronounced more like zeer-escape). The term 
was coined by the Denver Water Department in 1981, are derived from the Greek word “xeros”, meaning dry.
There are 7 principles that make up the concept of Xeriscape: planning and design, improving the soil, creating practical turf areas, irrigating efficiently, proper plant selection, using mulch, and maintaining the landscape.
While I am not sure EXACTLY when the 7 principles were first released (my guess is a few years after the term Xeriscape was first used), I have often wondered whether an update was needed, or if the same 7 principles would be adopted exactly the same today.
While today Xeriscape remains as relevant as ever, there are some important observations I have made through experience regarding the 7 principles, common misconceptions about them, and how they relate to landscaping in today’s rapidly changing world. Therefore, I thought it might be helpful to revisit and add updates to the original 7 principles:
Principle #1: Planning & Design
Updates: Planning and design is as important today as ever. Landscapes continue to get more complex as dozens of new plant choices are introduced each year, along with advances in irrigation systems and controllers. The more complex a project gets, the more benefit is gained from careful planning and design.
Another important development has been the landscape architecture license act of 2007, when Colorado joined the rest of the country in requiring that landscape architects be licensed, and that all commercial and large residential projects (greater than 4 units) have landscape plans that have been prepared by a licensed landscape architect. While this may have raised the cost of design somewhat, a good efficient design will always pay for itself by minimizing surprises during construction, allowing plans to be competitively bid, and lowering maintenance costs over time.
Misconceptions: Xeriscape can only be done in one style. A design will make the project cost more.
Principle #2: Soil Improvements
Updates: This is one area that needs to be looked at closer. The intention of this principle should be to “analyze and improve soil when needed, depending on what plantings are proposed”. The problem has been that many cities and municipalities started to require that all landscaped areas have large amounts of amendment incorporated into the soil over the entire landscaped area, and even requiring dump tickets from the contractors to prove that the amendments were placed.
While this is a good idea for bluegrass and for some types of plants, there are many other plants were the amendment is detrimental to plant health. Many of the very xeric and native plants prefer the native, rockier soil, and can suffer from root rot if soil is heavily amended with organics. I personally think that the amendment should only be tilled into new bluegrass areas, and in the individual planting backfill of those plants that will benefit from it.
Misconceptions: All plants require soil improvements.
Principle #3: Practical Turf Areas
Updates: I am not sure whether the original principle read “Practical Turf Areas” or “Practical Bluegrass Sod Areas”. One of the trends I am seeing that we are starting to use in our designs is the creation of “turf” areas from groundcovers and/or spreading perennials and shrubs. The questions that one needs to ask is not only where will the lawn areas be, but does an area really need to be a “lawn” at all?
Many of the bluegrass turf alternatives are very difficult and sometimes expensive to get established. If an area of the landscape will not be used for games and high foot traffic, then why substitute a hard-to-grow lawn alternative for bluegrass when there are many good spreading plants that are easy to grow? In other words, if a “turf” area will not be used, it simply becomes a low growing visual element, in which case many planting alternatives should be explored.
Misconceptions: Xeriscape means no grass, and bluegrass turf cannot be used in a Xeriscape.
Principle #4: Efficient Irrigation
Updates: Many advancements in irrigation have been made in the past several years, making it possible to irrigate even more efficiently. However, many of these benefits have been over-hyped. While I am all for making our irrigation systems more efficient, this approach does not address the underlying issue- how much water does my landscape REQUIRE to remain healthy? Only by installing water efficient landscapes will any major impact be made.
Misconceptions: If one installs new irrigation heads and a smart controller, the amount of water they will need to use will go down significantly.
Principle #5: Proper Plant Selection
Updates: This principle goes hand-in-hand with a good design. One of the overlooked aspects of this principle is a phenomenon known as “micro-climates”. Microclimates are small climate differences that occur in the landscape due to sun vs. shade relationships, water availability and retention, wind, soil differences, etc. Every day in this business I am reminded how plant selection is impacted by these micro-climates.
One area of debate is the natives vs. non-natives argument. I am firmly in the non-natives camp. There are some amazing native plants that I love to use, but there are also many non-natives discovered every year that meet the needs of our varying miro-climates.
Misconceptions: Only native plants are appropriate to use.
Principle #6: Mulching
Updates: The biggest problem I see with this principle is that all mulches are not created equal. There are cost, aesthetic, and weight differences between wood mulch and rock mulch. Not all plants like being heavily mulched, and some prefer rock mulch over wood mulch, for many of the same reasons some plants do not like a lot of soil amendment. As a result, wood mulch seems to be getting a bad name for Xeriscapes. I have even seen some cities write into code that wood mulch cannot be used for a low water-use zone. But wood is often quite a bit less expensive than rock mulch, and is WAY easier to move around, plant in, and make adjustment to than rock.
The bottom line on mulching- there are different rules to follow based on the type of mulch you are using. If you use wood mulch, use a thin layer and be sure not to over-water. If you use rock, remember that it will be difficult to add plants later or make changes to rocked areas. Also, keep in mid the aesthetics- I feel that too much rock can make a landscape seem a little too harsh, and but having a combination of mulch types can help to visually break up large areas.
Misconceptions: All mulch is the same, all plants love being mulched.
Principle #7: Maintenance
Updates: This is the most undervalued principle. For every 10 beautiful landscapes that I have designed and enjoy visiting time and again, there is at least one commercial landscape where even the most basic maintenance has been neglected. Shrubs have been sheared off into little balls right before they were about to flower, weeds have overtaken a bed area, plants have been over-watered to death.
The biggest piece of advice I can give to property owners or managers is this: walk your landscape once in a while, and make maintenance adjustments based on what you see. Remember that plants are living things, and your job is to understand what will allow each plant to flourish naturally, with the least amount of interference (such as over-watering, over-pruning, etc.) while at the same time minimizing negative factors such as pests, weeds, etc.
Misconceptions: All plants like more water, all shrubs need to be pruned, all plants have similar needs.
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 Guest Writer
If you’re in the market to replace your existing deck or want to build a new one, you will want to know what products are available and what your contractor can do with them.
A beautiful deck starts with careful planning and design. The best looking deck often reflects some architectural elements from the house and uses them in the deck. If you have multiple decks on your home consider using matching handrails and decking material for uniformity. Consult with your builder or designer for the many options available today.
Overall deck costs tend to range from $25-$35 per square foot and cost varies due to height and complexity of construction. The cheapest decking material on the market is probably pressure treated pine the most expensive include exotic hardwood species and top-end coated composite decking. Here is a quick run-down on some of the decking materials available:
Decking Materials:
Redwood – soft wood prone to damage from hail, includes the removal of old growth forests that take centuries to recover. Redwood takes hundreds of years to mature and therefore is not a sustainable wood source. Redwood coast around $3-4 per linear foot depending upon the quality ordered.
IPE – Brazilian rainforest lumber that is very dense (hard) and durable. It has a dark color and requires pre-drilling for fasteners. I do not know of any that is sustainably grown / harvested lumber. IPE costs around $4 per linear foot depending on thickness used.
Tigerwood – Brazillian or African rainforest lumber that is very dense (hard) and durable. It has a light dark color variation (tiger striping) and requires pre-drilling for fasteners. I do not know of any that is sustainably grown / harvested lumber. Tigerwood costs around $4 per linear foot depending on thickness used.
Cedar – Soft wood prone to damage from hail, be sure to specify better grades of wood and tight knot or better, can come rough sawn for beams or trimmers and works well for handrails. Tight knot cedar cost around $2 per linear foot and the price almost doubles for clear cedar.
Pressure treated pine: Typically made from southern yellow pine which is pressure treated forcing chemicals into the wood that resist rotting and insect damage. The treatments usually contain copper compounds & other chemicals that are highly corrosive to metals, so extra zinc treatment to galvanized fasteners is recommended to avoid rusting. Older treated wood, produced prior to 2004, often contain arsenic & chromium which can be easily released if burned. It is important to allow the wood to dry out prior to staining or sealing. Pressure treated wood is prone to warping, splitting and twisting and these qualities seem to be exacerbated in dry climates. I believe that staining & sealing these woods can help their look and performance. P.T. pine should be either screwed in place nailed with 16d ring shank nails all fasteners should be hot dipped galvanized.
Composite:
Should you use real wood or composite decking? In the last ten years composite decking materials (plastic/ wood particles glued together) have taken hold of the market and are used on over half the decks being built. Several companies use 90% recycled plastics in their products which will help reduce waste. However, I do not know of any composites that are recyclable when they need replacement. If decking could be continually recycled it would truly be a sustainable product, but no companies, to my knowledge, have produced such a product. All composite decking materials rely on a type of adhesive or glue that bond all of the plastic and wood particles together. These adhesives can be any number of polymers(resin) some which can cause environmental concern if released into the environment especially if burned. The life span of composite decking is similar to a wood deck that is maintained, around 25 years. Eventually all decking materials will end up in a landfill.
There are around ten different companies producing composite deck materials in the U.S. with Trex being one of the first and widely know. These materials include decking and handrail systems and most companies offer different product lines that vary in color and consistency. One California company even offers a bamboo composite BamDeck which uses 30% bamboo and 70% recycled plastic.
The cost of composite decking varies from $2-$4 per linear foot of decking board. Common sizes for composite decking boards are 12’, 16’, 18’ and some 24’ lengths are available from certain manufacturers. Try to design your deck so that no butt joints are required. Composite boards require spacing butt joints from 1/8”-1/4” for board expansion which can be unsightly.
THE GOOD
- Composite decking does not require as much maintenance as natural wood products.
- Does not splinter or split.
- Have built in slip resistance.
- Are consistent in color, shape, and texture.
- Grooved boards can utilize hidden fastener systems which are attractive.
- Boards can be heated and bent into circular patterns.
- Boards are often made with recycled plastic materials up to 90%, which make it more sustainable.
THE BAD
- Boards without a pvc treatment are prone to staining from many different sources. PVC treatments usually cost around $1 more per linear foot of board.
- Material holds heat and can reach temperatures that will burn bare feet in the summer.
- Material is not structural and typically requires a maximum joist spacing of 16 inches, which also limits what can be done with handrails.
- Material shrinks and swells more that wood which requires spacing at butt joints if used.
- Material requires pre-drilling in many circumstances for fasteners.
- Catastrophic failure, rapid deterioration is possible and almost all manufacturers have had to warranty their product for this reason at one time.
- Material is not recyclable.
- Polymers used to glue product together can be harmful if released into the environment, i.e. burning.
People often ask me what is the best composite to use and to be honest I don’t know. The reason for this is that almost all of the companies making composite materials have produced materials that have failed and needed to be replaced.
In 2009 Louisiana Pacific recalled around 48 million linear foot of decking that was sold under three different trade names (WeatherBest®, ABTCo., and Veranda®). Many other companies have had warranty claims for products that are less than five years old. When composite decking fails you will often notice that the color comes off like chalk when you rub it with a finger.
Once composite decking boards start to fail, they can simply start to rot or you may notice flaking, splits, bubbling or other abnormalities. Boards can also break between joists in extreme failures causing injury. Warranties vary from company to company, but in general you can expect a limited 20 year warranty. One thing to note is that the manufacturer’s warranty will only cover material replacement, not labor to remove the old boards and replace them, which can be a substantial cost. Therefore, do your homework and make an informed decision based on a company’s track record.
Some things you should consider if you are planning to use composite decking:
- Texture (slip resistance) especially in frost prone areas.
- Color – try to compliment your homes color. Most composite deck materials fade 30% in the first year and then stabilize. Some even change color so look at samples that have been weathered when possible.
- Cost – almost everyone is on a budget so pick the best material you can afford.
- Warranty – since there have been failures in the past research the company’s products that you are considering and find out their track record and read the fine print on warranties.
- Maintenance – consult manufacturer’s suggestions but most can be cleaned with mild soaps and water.
There are a lot of things to consider when it comes time to build or replace a deck. A new deck can cost as much as a new car so take the time to weigh your options and hire a competent builder. I suggest that you not only talk with a builder’s past client but also take the time to see one of their completed projects.
No decking is completely environmentally friendly or sustainable. In general, many of the natural wood decking products available are from hardwoods or slow growing softwoods which make them less sustainable. Pressure treated southern yellow pine is a faster growing, more sustainable wood product but it utilizes chemicals for rot and insect resistance. If the composite decking industry can develop a product that is recyclable and will consistently perform it will climb to the top of the sustainability chart and my “A” list.
This is a guest post by Bruce Kehr. The owner of Sunlit Builders, LLC, Bruce is one of the top deck builders in Colorado. You can reach Bruce via email at [email protected].
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by Matt Corrion
Ornamental grasses are more popular than ever, and for good reason. They can add texture to the landscape, and they are tough plants that are easy to grow in a variety of conditions. 
Ornamental grasses can also add beauty to the winter landscape.
But should ornamental grasses be cut back to the ground in winter?
Most ornamental grasses develop tall seed heads late in the summer that naturally persist through the winter. When temperatures start to drop the plant will die back, leaving the dried foliage, stalks, and seed heads. The general rule that you should cut back the grasses before the next growing season, so that the new year’s growth will be more vigorous and healthy.
I have found a couple of exceptions to this here in the Denver area, particularly with Mexican Feather Grass (Nassella tenuissima), which did not regenerate as well or look as good the year after I cut it back. I have since started leaving it uncut, which results is the new growth coming up right through the beautiful finely textured golden old growth. But with most varieties, they should be cut back before new growth starts in the spring.
So the question, then, is whether you should cut them back in the fall, or wait until the spring. Many people enjoy the colors and movement that these elements provide in winter. Others prefer a more “neat” or formal look.
I thought it would be interesting to explore the advantages each approach:
Advantages of leaving the grasses for the winter and waiting until the spring to cut them back
- When shrubs lose their leaves, and perennials wither to the ground, grasses can provide form in the landscape
- Texture: Interesting textures can stand out, collecting frost or snow, and reflecting sunlight
- Movement: Winter winds and soft breezes can move and sway the stems and seed heads of ornamental grasses
- The grasses can add color to the drab winter landscape, including shades of reds, yellows, browns, and blues
- Upright grasses can be used to help screen views when deciduous plants have lost their leaves
- The grasses can provide habitat and shelter for birds and other small animals
Advantages of cutting back ornamental grasses right away in the fall or early winter
- This can be interesting and different look, I have seen some nice formal plantings that looked stunning with the grasses cut back
- Some grasses hold their form better than others, while some varieties may flop over under heavy snow
- Cutting them back may give the impression (rightly or wrongly) that a commercial landscape is being better maintained
- In some cases the grasses may block sight lines, such as to important signage in a shopping center
- In high foot traffic areas, it may be beneficial to cut back ornamental grasses to avoid them being trampled
So what do you think, is one method better than the other? My personal taste is to leave the grasses up all winter, but there are situations where you may want to cut them back. And you can always decide to cut them back later, if you feel the need to tidy them up.
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
Brrrrr… It’s cold out there! The last thing you are probably thinking about is landscaping. Or, if you are like me you already have the itch to get outdoors and are counting the days until spring. Whether you are a restless home gardener looking for reasons to get outside, or you are performing maintenance on a commercial property and want to do all you can to have it look great some spring, there are many tasks that can be accomplished over winter. Get the hot chocolate ready!
Key Dates
- Late February: Stop any pruning from this point on- spring is right around the corner, and woody plants are developing buds and preparing for the new season.
- Late March: Plants will begin to emerge for spring at this time. As plants (especially Xeriscape plants) emerge and show signs of new growth, begin to remove any heavy mulching that was done to protect them over the winter.
Trees and Shrubs
- Apply tree wrap to the trunks of young trees, early in the winter. This protects the bark from sun-scalding and damage from harsh winter winds.
- Watch for any heavy, wet snowfall. This can break off branches of trees and do a lot of damage. Shake heavy snow from trees and shrubs that are bending and showing stress. While this can be a threat throughout winter, trees are particularly vulnerable in early spring when buds and leaves are beginning to emerge, because this creates more surface for the wet snow to stick to.
- Hand-water your trees and shrubs if dry periods persist for a month or longer and the ground is not frozen. Keep in mind that areas facing the south and west will need water more than areas with northern exposure where snow will stay on the ground longer. Water in the middle of afternoon when temperatures are warmer (above 40 degrees Fahrenheit). You only do this about one time per month, and only if dry conditions persist.
- Make sure you have plenty of mulch around trees and shrubs- this helps maintain moisture and keeps the soil from drying out over the winter.
- Finish any pruning of trees and shrubs in January. When pruning trees, look to remove branches that appear likely to grow into each other or rub against other branches. When pruning shrubs, always try to maintain the natural size and growth habit of the species. Always use the right tool for the right cut.
Perennials and Ornamental Grasses
- Leave spent stems and seed heads on grasses and perennials until spring, to enjoy their winter beauty and to provide cover for birds and wildlife. If ornamental grasses and perennials have “flopped over” due to repeated snowfall, go ahead and cut them back now to achieve a neater look- otherwise, wait until early spring.
- Late in March begin to remove any heavy mulching that was done in the fall/winter to protect the plants and preserve moisture. We usually receive plenty of precipitation in March and April in the form of wet snow and rainfall. If there is too much mulch around the base of perennials and ornamental grasses (especially Xeriscape plants with low water-use requirements) then stem rot and root rot can occur if the mulch is too thick in the spring.
Lawns
- Minimizing traffic on lawns will help to keep from damaging the grass, especially if it has been a dry winter or the ground is frozen.
Winter Weather Considerations
- January and February are the driest months of the year (in terms of precipitation) for the Front Range of Colorado. Watch soil moisture closely, and hand water your plants if you receive little snowfall. In March, the level of precipitation generally picks up quite a bit.
Other
- If you are feeding birds, try to keep your feeders full as birds can become dependant on this source of food in winter.
- If it has been a dry winter, when you are plowing or shovelling snow strategically place snow around the base of trees and shrubs to provide added moisture.
- Start planning for design changes to your landscape for summer. Now is a good time to get your plans in order, and spring is the best time to establish new plants- so get ready early, because it will be here before you know it!
- Finally, sit back and wait for SPRING! A cozy fire and a warm drink will make the wait more bearable.
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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