Achillea lanulosa (Achillea millefolium var. lanulosa) (Yarrow)
Agave parryi neomexicana
Amelanchier alnifolia (Serviceberry)
Amorpha canescens (Leadplant)
Aquilegia barnebyi
Aquilegia caerulea (Rocky Mt. Columbine)[Read More]
Xeriscape: Native Plants
Xersicape: Non-Native Plants
Acantholimon glumaceum
Acantholimon hohenackeri
Acantholimon litwanovii
Achillea ‘Moonshine’
Achillea ageratifolia (Greek Yarrow)[Read More]
Curl-Leaf Mt. Mahogany
Curl-leaf Mt. Mahogany (Cercocarpus ledifolius)
This tall shrub or short tree is a beautiful broadleaf evergreen that is native to Colorado and much of the west up to 9000’. It’s narrow, curled leaves are an adaptation to reduce exposure to drying sun and wind; consequently it is very drought resistant, needing no irrigation after being established.The leaves are also thick, leathery, resinous and dark green above and pale below. Flowers are mostly inconspicuous and the fruit is only 1/4” long with a 2”-3” long silky tail. In dry weather these tails twist like a cork screw and with a little wind can be carried a good distance and then they will screw the seed right into the soil.[Read More]
2011 Plant Select Winners
Plant Select is a 25 year old cooperative program combining the efforts of Denver Botanic Garden, Colorado State University and some members of the local green industry. Their intention is to chose, propagate and promote plants that are well-adapted to Colorado conditions, colorful and are either little known or underutilized. The 2011 choices are a particularly excellent group.[Read More]
Xeriscape Herb Garden
Usually when we talk about xeriscape gardening, we think of rock garden kinds of plants or natives, but there are a lot of herbs that survive and even thrive in low water conditions. I learned about this from my own herb garden which went from low water irrigation to next to no watering. It had been established for ten years and then three years ago, I had to cut back the watering to only a couple times a year.[Read More]
A Xeriscape Harvest
For most people, harvest time brings to mind a cornucopia of veggies and fruits. For me, the end of this 2009 growing season has been a fruition of over 20 years of cultivating a xeriscape where most of the trees and shrubs have been watered 5 times a year or less. These self-imposed watering restrictions have demonstrated which plants can survive and thrive under serious water shortages. I have done this both to encourage water conservation in Colorado and to demonstrate that a dry western landscape can be beautiful.
The reason why 2009 feels like a harvest year is because many of my woody plants are now mature and because with all the rain we’ve been getting, my xeriscape has never looked better at the end of summer.[Read More]
Big, Bold, and Beautiful
If you’ve got room for some big splashes of color in a garden that is not pampered with water and fertilizers, here are some tough natives that will pay for their real estate.
Desert Four O’Clock, Mirabilis multiflora is a Colorado perennial that, like its annual cousins, blooms from late afternoon to mid-morning. The trumpet-shaped flowers are of a rich purplish rose color and virtually cover the foliage when the flowers are open, blooming for several months starting in July. The leaves are thick and blue-green. They look so innocent as seedlings, and then they grow and grow to a 3’-4’ mound, 1 ½-2’ high. The stems lie on the ground, providing a mulching effect.[Read More]
Growing Agave in Colorado
Most of us in Colorado know that Agave is the source of tequilla and Agave sweetener, but fewer have seen it growing here. Even more rare is the sight of Agave in bloom. The Century Plant doesn’t really take 100 years to bloom, but it does seem to take forever. After 13 years, my Agave parryi, whose bold and armed rosette finally achieved 31” in diameter and 16” tall, began this May to push up a bloom stalk. Then it skyrocketed 3”-4” A DAY until it reached eleven and half feet tall with a candelabra of rich yellow flowers. Eclectic horticulturist Bob Nold says in his book High and Dry, “Their flowering, mostly, is as spectacular a thing as the plant kingdom has invented….”[Read More]
Drought Resiliency
Drought resiliency is normally thought of as the ability to spring back after a drought or maybe it means tolerant of drought. But when a plant is stressed by having little water, its ability to survive and even thrive is influenced by other factors, some of which are Health, Vitality, Strength and Immune function.
The word Sustainability has become popular as a goal, but the word is too static. A more active word is Re-generative. We can “create” gardens that not only can maintain, but also support the abilities of Life to regrow, multiply, defend itself against predators and add to the vitality of other living things around it.[Read More]
Drought Water Restrictions
Drought, Water Restrictions and Gardening: How Can They Go Together?
I think we were all caught off guard by this drought, by how fast we were forced to see dying trees and brown lawns and by the difficult discipline of watering restrictions. This was especially true in Boulder and Lafayette where mandatory restrictions began in May. Actually, 2002 is the third year in a genuine drought, which some of us without city water supplies can confirm. This year all around Boulder, Red Twig Dogwoods turned brown, linden leaves were scorched, Norway Maples suffered, many viburnums were looking very stressed, and trees in medians defoliated or died. Gardeners caught in the crunch between weeks of hot, dry weather and few opportunities to water, held off most of their planting projects; some started talking about moving away to where they could garden. For Denver and other Colorado cities, next year could be much worse.[Read More]
July Color in the Xeriscape Garden
Xeriscape? Are you kidding? With all the rain we’ve been getting, isn’t the drought over?
As I understand our current water situation, water restrictions are still in effect for the Denver area, Colorado Springs has had a very dry spring until July and is under water restrictions, the Western Slope has been dry, New Mexico has been dry until July; and Montana and South Dakota are having severe droughts. What this means is that the wonderful moist season we are enjoying in the Denver area depends on ephemeral conditions we cannot count on. In addition, much of our water comes from the Western Slope where weather patterns can be quite different from our own, so even if our gardens are getting watered, it doesn’t mean our reservoirs will be full. We live in a semi-arid environment and water conservation and xeriscaping will be increasingly important as our population grows, especially if global warming increases our temperatures.[Read More]
On The Dry Side
Plants that can survive and even thrive with little water are always valuable in Colorado where we get 15”-18” of precipitation most years. But when a real drought comes or when limited snowfall in the mountains means water restrictions down here, then xeriscape plants are essential in our gardens
Because the well at Harlequin’s Gardens nursery is so poor, my rockery garden has been on water restrictions for the last 25 years. Here are some plants that have performed well in my garden that is watered only 3 to 7 times a year.[Read More]
Opportunities and Tricks of Xeriscape
Since the drought of 2002, there has been some real progress in understanding and appreciating xeriscape or water-wise landscaping. And yet some people thought ‘the drought is over, and we can go back to assuming that we have as much water as we want’. But it is predicted that with climate change we will have more and longer periods of drought, and it would be painful to be as unprepared as we were in 2002. That was our wake-up call. Fortunately, gardeners are generally smart and caring people, and their values are changing. They are more interested in sustainable landscapes, and they want more economical landscapes and gardens that need less water, time, energy, and money. And of course that means using plants and methods that are adapted to Colorado conditions. [Read More]
Some Drought-Tolerant Gems
Plants that tolerate or even revel in hot, dry conditions are always in vogue in Colorado. We may be blessed with moisture in the spring, as we had this year, but by June or July our vegetables need regular watering and east coast woodland plants are melting. There are some plants, however that are adapted to hot and dry conditions. Some are natives and some are from other regions of the world that have similar drought stresses as we have here.
These gems are ones that we have tested at Harlequin’s Gardens where none of our demonstration gardens are watered more than once a week, and others only 5 or 6 times a year. We can recommend these plants as successful and enjoyable under mandated or self-imposed watering restrictions.[Read More]
Testing Xeriscape Groundcovers
TESTING XERISCAPE GROUNDCOVERS TO REPLACE LAWN AREAS
Whether this turns out to be a drought year or not, the idea of conserving water is probably as vital to our future as educating our children. As long as the human population grows, the demand on our water reserves will continue to rise, forcing eventual water-rationing even if the supply stays the same. And as we have seen this year, we can’t count on a bountiful supply from the heavens. Ten years ago these ideas, and the fact that my own water source is a very low-producing well, got me to thinking about how much water we use in Colorado to water our lawns. We know that xeriscape plants use less water than bluegrass, so why couldn’t we use large areas of certain low-water plants to replace lawn, which could greatly reduce the demand on our valuable water? In order to test a variety of xeriscape plants that might function as replacements for Kentucky Bluegrass, I built a 104′ x 6′ demonstration garden which will be on the 2002 Xeriscape Garden Tour, taking place in Boulder June 29th and 30th.[Read More]
The 2002 Drought
Drought, Water Restrictions and Gardening: How Can They Go Together?
I think we were all caught off guard by this drought, by how fast we were forced to see dying trees and brown lawns and by the difficult discipline of watering restrictions. This was especially true in Boulder and Lafayette where mandatory restrictions began in May. Actually, 2002 is the third year in a genuine drought, which some of us without city water supplies can confirm. This year all around Boulder, Red Twig Dogwoods turned brown, linden leaves were scorched, Norway Maples suffered, many viburnums were looking very stressed, and trees in medians defoliated or died. Gardeners caught in the crunch between weeks of hot, dry weather and few opportunities to water, held off most of their planting projects; some started talking about moving away to where they could garden. For Denver and other Colorado cities, next year could be much worse.[Read More]
Three Xeric Plant Select Favorites
Here are three hardy, xeric and floriferous plants that are successful in western gardens.
Russian Hawthorn, Crataegus ambiguus was tested at the Cheyenne Horticultural Station and found to be well-adapted to the west. It is native to Armenia, Iran, Russia, Ukraine and Turkey. I have a 20 year-old specimen growing without irrigation along with many native shrubs. The mature size is 15′-20′ high and wide in our area. The branches grow quite horizontally which gives it natural character. It lends itself to a bonsai/character style, and I have been growing one in a big ceramic pot for 10 years. The finely cut leaves give a soft appearance and in May it blooms with profuse white flowers that are attractive to bees and butterflies and followed by showy red berries in August/September that are eaten by birds. Very dry conditions can result in fewer flowers and fruit. Like apples, to which Hawthorns are related, the seeds contain some cyanide, so should not be eaten, but the berries are edible and make a respected heart tonic.[Read More]
Xeriscape Perennials That Withstand Colorado
“The quality of mercy is not strained
It droppeth as the gentle rain from heaven.” Shakespeare
It was great to have a long cool spring with plenty of moisture, but since it followed the very hot temperatures and drought of 2002, it really felt like a merciful blessing. Now instead of dying trees and brown lawns, the streams are gushing, the reservoirs brimming, the wildflowers are extravagant and the birds are joyfully singing. Those plants and gardens that survived 2002 have never looked better. We’ll take it.[Read More]
Xeric Perennials that Thrived During the 2002 Drought
Xeriscape Perennials Thriving in 2002 Drought
Acantholimon glumacium
Acantholimon hohenackeri
Acantholimon litwanovii
Achillea ‘Moonshine’
Achillea ageratifolia (Greek Yarrow)[Read More]
The Drought Response
Responding to the worst drought in 100 (300?) years has been confusing, disturbing and difficult. The main unanswerable questions are, “How long is it going to last?” and “Is global warming or other conditions going to cause this kind of drought to be more common place?” Implicit in these questions is the question being asked by water utilities, city governments and members of the Green Industry: “How much money should we invest in changes that will conserve water?” If in two years the drought is over and will not be this bad again for 100 years, then why bother to reinvent our utilities and businesses? On the other hand, if water providers, city councils and the Green Industry are not proactive about water conservation, and the drought cycle lasts for a long time, consequences could be devastating, and the public could get furious.[Read More]
Xeriscape Perennials And Biennials For Sun
Note: plants listed in bold are native to our region
Acantholimon hohenackeri
Acantholimon litwinowii
Achillea ageratifolia
Achillea filipendula ‘Moonshine’
Achillea lanulosa
Achillea millefolium ‘Cerise Queen’
Xeriscape Vines
Xeriscape Vines For Sun
Campsis radicans / Trumpet Vine
Celastrus scandens / Bittersweet
Clematis ligusticifolia / Western Virgin’s Bower
Clematis tangutica / Golden Clematis
Humulus lupulus / Hops
Humulus lupulus ‘Aureus’ / Golden Hops
Humulus lupulus neomexicana / Native Hops
Parthenocissus quinquefolia / Virginia Creeper
Polygonum aubertii / Silver Lace Vine
Solanum dulcamarum / Nightshade
Wisteria floribunda / Japanese Wisteria
Wisteria macrostachya ‘Aunt Dee’ / Aunt Dee Wisteria
Low – Water Vines For Shade & Part – Shade
Akebia quinata / Japanese Akebia
Ampelopsis brevipedunculata / Porcelain Vine
Euonymus fortunei ‘Minima’
Euonymus fortunei ‘Coloratus’ / Purple Wintercreeper
Hedera helix / English Ivy
Parthenocissus quinquefolia / Virginia Creeper
Trees For Xeriscapes
In general, shade trees are not very tolerant of drought. Some people have gotten the idea that since trees have big root systems, they are less vulnerable to dry conditions. Unfortunately this is not true. Truly xeric trees that are native to arid regions are usually small, more like big shrubs. Even in our semi-arid region, photos from a hundred years ago, show very open and unshaded areas where we now have our urban forests. Most shade trees come from forested areas with much more rainfall and deeper, richer soils. On top of that, our trees are often made to grow in very confined areas in heavily compacted soils. So even under normal circumstances, big trees have a hard life here in Colorado. Therefore, during a drought, we must take extra care to make sure they survive by deeply watering at least once a month. If you multiply the diameter of a tree in inches times 10, you will get the recommended gallons of water required per watering. This water should be applied, not next to the trunk, but in a wide band around the drip line. Your best chances of establishing a tree during water restrictions are to:[Read More]
Five Little-Used Xeriscape Shrubs
Fortunately, there are many choices of drought-tolerant shrubs. And not only can they tolerate drier conditions, the fact that they are taller than most perennials and groundcovers helps them to compete better with weeds, giving them a greater survival potential in untamed, harsh or more industrial locations. In native ecosystems, it is often the shrubs that begin to pioneer a barren ground, and the shade and wind-protection they create, gives more favorable microclimates for other plants to germinate and find a home. There are many fine non-native shrubs for xeriscapes, but in this article, I am mostly going to describe some of my favorite native shrubs for drier conditions.[Read More]
Will The New Lawn Be a Meadow?
I used to be prejudiced against grasses because I associated grasses with the American monoculture of Kentucky Bluegrass that we all know as “the lawn”. But after testing many kinds of xeriscape plants for over 20 years I finally realized that most sustainable ecosystems have grasses mixed with the other plants. And I also came to appreciate that grasses are strongly self-replicating and that they can be more easily grown from seed than most perennials, so that installation and maintenance costs could be much less. I still think low-water shrubs and Colorado-adapted perennials have an essential place in a sustainable landscape, but I have been wondering how grasses could fit in. Of course Piet Oudolf and Kurt Bluemel have shown the potential for using grasses in a garden, but their examples look well watered and seem like they would be high maintenance. The prairie model so successful in Wisconsin and the Midwest focuses on tall-grass prairie that is out of place here, and so I have been wondering how grasses could be used in a Colorado-sustainable landscape.[Read More]
Groundcovers Project in its 18th Year
In 1993 I sent a survey to 29 local horticulturists to get their suggestions on the best groundcovers for a demonstration project we were planning at Harlequin’s Gardens. I asked them to list 5-10 groundcovers that could be used to replace bluegrass in low traffic areas, that would need a quarter to a half the water of bluegrass, have few pests and diseases, would grow densely to limit weeds, would look good in most seasons and would not be invasive in gardens. The survey was typed on a typewriter and most of the replies were hand-written. People did drive cars back then. But that was a long time ago and I had a lot to learn.[Read More]
Lavandula – The Lavenders
Lavenders are great xeriscape perennials for Colorado, which bloom in the heat and dry of July and August. They are native to the rocky hillsides of the Mediterranean region. Here as well, they like good drainage, full sun, our alkaline soil and dry, loamy humus. Lavenders are aromatic herbs with gray foliage, the leaves as well as the flowers being strongly fragrant.[Read More]
Lawn Alternatives and Groundcovers
In our American communities, one of the responsibilities of home-ownership is to keep the ground covered. Bare earth, like weeds, indicates lack of care. So then, how do we cover the ground? The cheapest, fastest, and easiest way is to roll out bluegrass sod. “Instant” landscapes can be accomplished with a supervised construction crew that knows little about plants. And as long as water was plentiful, bluegrass was the unquestioned solution.[Read More]
Xeriscaping with Natives
What group of plants has the longest proven record of success in Colorado for enduring the radical ups and downs of our weather, including droughts? Our native plants, of course. And if we give them similar conditions to what they have in nature, they will succeed with little care. Here are a few of my favorite native plants that have thrived in my xeriscape garden for the past 10-15 years.
Liatris punctata, the Dotted Gayfeather stores its energy in a thick taproot that helps it produce flowers even after a dry summer. The tufts of rough, narrow leaves are little-noticed until they shoot up their thin flower spikes to 10”-16”, and burst into bloom with lavender-violet “feathers” in August or September. They are especially dramatic in groups of four to ten plants, and they can continue to bloom for a month or more. Liatris punctata is native to the foothills and plains of Boulder County, and unlike cultivated varieties, needs no supplemental water once established.[Read More]
Trees For Xeriscapes
In general, shade trees are not very tolerant of drought. Some people have gotten the idea that since trees have big root systems, they are less vulnerable to dry conditions. Unfortunately this is not true. Truly xeric trees that are native to arid regions are usually small, more like big shrubs. Even in our semi-arid region, photos from a hundred years ago, show very open and unshaded areas where we now have our urban forests. Most shade trees come from forested areas with much more rainfall and deeper, richer soils. On top of that, our trees are often made to grow in very confined areas in heavily compacted soils. So even under normal circumstances, big trees have a hard life here in Colorado. Therefore, during a drought, we must take extra care to make sure they survive by deeply watering at least once a month. If you multiply the diameter of a tree in inches times 10, you will get the recommended gallons of water required per watering. This water should be applied, not next to the trunk, but in a wide band around the drip line.[Read More]