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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]

Beyond GMOs and Petroleum Farming

Four years ago I was among the group of Boulder County residents who were asking to ban GMOs on our publically-owned farm lands. The Commissioners at that time voted to add GMO Sugar Beets to the already approved GMO corn, but they also increased the acreage of land to be used for organic agriculture and agreed to take another look at neonicotinoid use if there was new evidence. There is now new evidence on GMOs, Roundup that is used on 80% of GMOs and on neonicotinoids linked to the death and weakening of all our insects, including bees.

So in 2011, in order to find out if there were practical non-toxic options to manage larger pieces of farm land (like 200-300 acres), I traveled to Ohio to an Acres USA Conference. Attending that conference were over a thousand farmers and ranchers. ACRES has been guiding eco-agriculture for 45 years now; the last conference I had attended was in 1977. I met farmers and attended talks by farmers who were managing 100-1000 acres without GMOs and without toxic chemicals.[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]

Quaking Aspens

Leave them to the Mountains OR Plant them at Home?

Populus tremuloides or Quaking Aspen is not only one of the best-known native trees here in Colorado, but it is said to be the most widely distributed tree of North America. Its narrow, roughly pyramidal form is commonly 25’-30’ tall and 15’-20’ wide, although it can get much larger. The leaves are shiny, dark green above and light gray-green beneath which makes the tree shimmer in the breezes. Also its whitish trunk adds to its attractive architecture. Then in the fall the leaves can turn a rich golden yellow which look glorious on the tree and lovely on the ground. It has a suckering habit which inclines it to clumps and which has put aspen in the running for the world’s largest being.[Read More]

Bigtooth Maple

Bigtooth Maple, Acer grandidentatum, is native to the far southwest corner of Colorado in a place known as Sleeping Ute Mountain. It is common in canyons, northfacing slopes and along mountain streams in Utah, Wyoming and west Texas from 5000′ to 8000′. Although most often listed as a separate species, Bigtooth Maple is sometimes called Western Sugar Maple, therefore, a subspecies of Acer saccharum. Its other names are Canyon Maple and Wasatch Maple.[Read More]

Bur Oak

BUR OAK—QUERCUS MACROCARPA-MOSSY CUP OAK

One of the most successful oaks for Colorado is the Bur Oak. It is adaptable to our clay soils and tolerates our alkaline conditions better than most oaks. In harsh, droughty areas this tree can be a low shrub, but on rich, river-bottom land can get 170’ high and 6’-7’ in diameter; but most often grows 50’-70’ high. The trunk is often thick and short with deeply furrowed bark, and the stout branches often extend almost straight out making the tree as broad as tall. The leaves are deeply lobed only in the bottom half and these lobes are rounded not pointed as with many other oaks. The acorns are distinctive in that there is a mossy fringe around the cap. The overall effect can be quite grand and sculptural, sometimes like a Chinese painting. The short taproot is surrounded by a massive root system which is strongly competitive. This is why old specimens often are standing alone.[Read More]

Catalpa

Western (Northern) Catalpa- Catalpa speciosa

It is surprising that a tree that looks so different from the other Colorado-adapted trees, is so successful. What stands out immediately are the huge leaves which can be 3”x 6” or even 6” x “12” and are heart-shaped. And in June, this large shade tree blooms exquisite, ruffled, bell-like, white, fragrant flowers with yellow and purplish coloration .And in the fall the passerby might be surprised to see the long thin pods 10”- 18” long.[Read More]

Champion Trees Show More Possibilities

Growing trees in Colorado, especially big shade trees, can be very challenging. Few of the specimens in our community “forests” are native to Colorado, and areas where big trees are abundant are often so different from our conditions that those trees do not adapt well here. Some of the difficulties trees face here are: alkaline soils, nutrient-poor and shallow soils, low humidity, hot and drying winter sun, strong winds, untimely wet snows in spring and fall, rapidly changing temperatures, and low rainfall. Add to these the confining root zones in which many trees are growing in urban environments, and it is easy to understand why our trees are often stressed, subject to borer and fungus problems, broken and short-lived.[Read More]

Why Plant A Once Blooming Rose?

I know of one lilac that has some repeat flowering in the fall, but I’m not aware of any spireas, mockoranges, shrub honeysuckles, forsythias, serviceberries, butterfly bushes, rabbitbrushes, cotoneasters, or other shrubs that repeat their flowering cycle. Why is it, then, that many gardeners demand continuous flowering roses ? We want them, of course, because they exist.

The fixation on constant flowering is encouraged with annuals, which, of course, don’t really start blooming until late spring or summer and then the first winter, they die. And seasoned gardeners know that the search for perennials that “bloom all season” leads to the proper selection of many species that will bloom in succession. So when we hear of roses that bloom from May or June through September, we think we have found the holy grail. However there are qualities besides repeat flowering which could entice us to cultivate the so-called “once-blooming” roses. I would like to share these not-so-obvious reasons with you.[Read More]

Kentucky Coffee Tree – Gymnocladus dioica

This member of the pea family (Fabaceae) can get 50’-60’ high and 30’-40’ wide, though most that I’ve seen in Colorado are under 45’. Nearly everybody thinks of this tree as interesting or picturesque.The branching is more open than most trees and the bark is gray to dark brown, rough and deeply ridged even on small branches. The leaves are  bluish-green and somewhat tropical-looking being double compound, each one 18”-24” long and forked with small leaflets alternating on the stem. Fall color is yellow. As the species name implies, this tree is dioecious, having the male and female flowers on separate trees. The flowers are greenish-white, supposedly fragrant and not conspicuous. On the female trees, tough, leathery seed pods follow that are 4”-6” long and 1 1/4”-2” wide. These hang on after the leaves fall and into the winter.[Read More]

Hackberry

Common Hackberry  (Celtis occidentalis)

Why would anybody be interested in a tree that is just the common variety? In this case, we Coloradoans can be very interested because “common” means it will grow just about anywhere. In our harsh country that provides a good living for people planting and replanting and pruning and re-pruning trees, the Common Hackberry is somewhat of a relief. It will grow to 7000’. Our 25 below zero winters do not bother it as it is hardy to zone 2, which helps a lot in adjusting to our sudden warm-to-cold swings. It is also not picky about soils, tolerating both acidic and our usual alkaline conditions; rocky is fine, heavy clay is OK; it really likes rich, moist, but grows right along in poor, dry, windy, polluted cities. [Read More]

How to Plant a Tree

Planting a tree puts us in touch with one of the most essential parts of a tree that is often overlooked—the roots. When a seed germinates, the first part to develop is the root. The seed has stored nutrients, but if the plant is to live, it must immediately make a relationship with the nourishment of the earth. Then it can make the sprout that pushes into the sunlight to start photosynthesizing. So the first matter of importance in planting a tree is to honor its roots—their condition, their future environment and their nourishment.[Read More]

Interview with Alex Shigo

Alex Shigo is a world-renowned authority in arboriculture, the science of trees. His delving curiosity and sharp scientific analyses carried him beneath the bark into a realm previously little understood. He worked 26 years for the US Forest Service investigating decay in trees, and through the process of dissecting over 15,000 trees with a chainsaw, he has uncovered much valuable information about tree structures and tree systems that have revolutionized the practice of tree care. As he puts it in the preface to his book Tree Pruning, “A major problem throughout the history of tree pruning has been the scant attention given to pruning as it affects the health of trees, while great attention has been given to pruning as it affects the desires of man.” Even though he is busy writing, giving workshops and talks and doing consulting, he agreed to answer some pressing questions for The Colorado Gardener.[Read More]

Sustainable Roses for Colorado

Tea House Roses, photo by Nikki Hayden

Roses are certainly one of the world’s most beloved flowers, and yet many people have given up on them because they have gotten the reputation of needing frequent spraying, feeding and fussing. They got this reputation because for decades, hybrid tea and floribunda roses were bred mostly for special colors, a particular flower form and repeat flowering. Their value was judged more for the exhibition table than for the garden. Now, as more people have become aware of the dangers of pesticides and as the trend has moved to “care-free” shrub roses for the garden, rose breeding has shifted in the last ten years towards more sustainability.[Read More]

Mountain Ash

European Mt. Ash (Sorbus aucuparia)

This is surely one of my favorite ornamental trees for the front range which can be used up to 8000’.It is an upright oval tree spreading with age 25’-30’ tall aned 15’-25’ wide. If cared for, it will be attractive throughout the season. The bark is a shiny, orangy-brown. The serrated, compound leaves are dark green and in the fall turn yellow and reddish-gold. The clusters of flowers are white, blooming in spring with a peculiar fragrance that some people appreciate more when they’re gone. Clusters of red-orange berry-like fruit follow which color the tree through the fall, accenting the orangy leaf colors. These fruits are greatly loved by the birds and are in fact edible for people. They are known as Rowan berries and are used in Europe in making a brandy. In ancient times the Rowan tree, also know as the Quickbeam, was greatly revered by the Druids and used against lightning and witches’charms. The berries were considered extremely valuable having the “sustaining value of nine meals”, healing the wounded and giving a man the strength of ten men. I had to try this, of course, and found I couldn’t eat even 10 berries. Later I learned they need to “blet” or shelf-ripened. The birds do spread these around, and Mt. Ash seedlings are not uncommon.[Read More]

Pinyon Pine – Pinus edulis (Pinus cembroides edulis)

The Pinyon Pine has several advantages over other evergreen trees in a Colorado landscape. For one thing, its size doesn’t consume so much horizontal space. Compare the modest mature Pinyon at 10’-15’ in diameter with Austrian or Ponderosa at 25’-35’ diameter or Blue Spruce at 30’-40’ diameter. A few of these “average” sized evergreens look innocent when freshly planted, but who hasn’t seen them blocking sidewalks and doorways, tearing off gutters and shading solar collectors and windows in the winter? The Pinyon with its gently rounded top only gets 12’-20’ high, which suffices for many screening needs and still leaves the view. If it isn’t crowded, it stays branched to the ground with dense foliage of short, medium green to gray-green needles, two to a bundle. The cones are small 1 1/2”-2” long, brown to reddish-brown, which open to a rosette form and in the wild yield Pinyon “nuts”. These seeds are good-tasting and oily, with a piney flavor much appreciated by birds, animals and humans. They are also nutritious, being higher in protein and carbohydrates than pecans, but lower in fat. For some reason , these “nuts” are unlikely to develop in small urban plantings.[Read More]

Redbud

One of the most beautiful ornamental trees is the Eastern Redbud, Cercis canadensis. It is a native of the eastern and southern U.S. and has “naturalized” in older Boulder neighborhoods. It’s most distinctive feature is its reddish purple buds  followed by intense purplish-pink pea-like flowers in late April before the leaves come out. This wondrous and heart-warming display is greatly appreciated so early in spring but cannot be counted on if winters are too harsh.

It is a smaller tree 20’-25’ high and wide with attractive bark and heart-shaped leaves which are shiny and purplish when young. Fall color is yellow. It is said to be hardy  to zone 4 and we have many fine specimens in Boulder.[Read More]

Small Trees for Eastern or Northern Exposures

Shade trees 40’-60’ high and wide are great on the south and west sides of our houses and offices. They reduce temperatures and reduce cooling costs in the warm months, but they are not always appropriate. We don’t want dense shade where we grow most xeriscapes, rock gardens, herb gardens, most natives and many perennials. In addition, there is no need for big shade trees on the north side, and the morning sun is usually welcome on the east side of our houses and workplaces. And many plants prosper in morning sun and afternoon shade. It is also significant that a 20’ tree costs far less to have pruned than a 40’ tree. So it seems to me we should be growing small trees under 30’ tall on the east and north sides of our buildings.[Read More]

Stressed Trees: How to prune and care for them

Trees have it hard in Colorado. If it’s not the shallow and lean topsoil, it’s the low rainfall and low humidity, or it’s the heavy wet late spring or early fall snows, or like last November, it’s the dramatic temperature changes. After a warm and beautiful fall without a killing frost until November 11, we experienced a 77 degree drop in temperature between November 10 and November 12. This was one of the three largest temperature drops ever recorded in the Denver area, the other two were in December 2013 and January 2014.[Read More]

Penstemons at Harlequin’s Gardens

Below is a list of many of the varieties of Penstemons that we usually have for sale at Harlequin’s Gardens. Penstemons are in general very well adapted to xeriscape gardens in Colorado. Many of them are regional natives and there are several that are native in Boulder County. In general, they like full sun and good drainage, however many can be grown in our clay soils if they are not overwatered. Some are 3′ tall, some are ground covers. Many are blue or purple, some are orange or red and there are a few whites. It is good to sow their own seeds in the fall to create sustaining populations. Try them; they are beautiful and fun AND nearly all LIKE hot and dry conditions, once established.[Read More]

What’s Blooming in July?

Many gardeners think of Spring as the height of the ornamental gardening
season. Sure, so many of our best-known flowering plants – Tulip,
Crocus, Daffodil, Primrose, Peony, Lilac, Forsythia, Oriental Poppy,
Basket of Gold, Bearded Iris, are at their showiest in spring. But as we
pass to the other side of the Summer Solstice, a whole new palette of
blooms arises, including many Natives, lots of Prairie-dwellers and
Steppe plants, and hardy plants from South of the Border, bringing bold
color and attracting more and different beneficial insects and
pollinators to the garden. Here’s a list of many of those flowers to
inspire you![Read More]

Supporting Trees in Colorado

Trees do a lot for us humans, so we shouldn’t forget to give them some support. When I look at the treeless ten acre lot next to our nursery, or when I see an old photo of the CU campus with bare land around Old Main, I remember why we can’t take trees for granted in Colorado. Trees really have it hard here, but there are things we can do to help them survive and thrive.[Read More]

The Pruning and Care of Young Trees

Of all our plants, trees take the longest to develop and so it is not only heart-breaking, but a significant set-back to a landscape when a tree that is 10-20 years old is destroyed in a storm. Many of these disasters could be prevented with proper pruning early in a tree’s life. Besides preventing disasters, pruning trees properly when young will help them to develop more beautifully, make them stronger, less expensive to maintain as they get older and keep them healthier.

A young tree, like any young being, is vulnerable and needs some extra care. And trees are often a costly investment, both for the plant and for the planting. So since few arborists will come out for the fifteen minute job of pruning a young tree, and since few lawn crews are trained in proper pruning, it is good for home-owners to understand the basics of pruning in order to get their trees off to a good start.[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’

[Read More]

Tree Roots 1: The hidden support system

The roots are the hidden support system of our giant plants, the trees. They anchor their woody trunks to the ground, store food and bring in water, nutrients and oxygen. In this article I will discuss what is going on down there. In the next issue I will discuss more practical applications of this understanding.  

Far less is known about tree roots than about the trunk, branches and leaves. This is understandable since the roots are hidden from our view, and once you dig them up, they are no longer what they were. We are awed by the massive trees swaying over our houses and streets, but usually we give little thought to what is going on under the surface. However, when spring thawing is followed by powerful winds and we see an 80’ spruce toppled over with its roots in the air, which are only 9” deep; that gets us thinking.[Read More]

Tree Roots 2: The hidden support system part II

What would we do without trees? What structures could we invent and construct that would hang over our houses and offices, providing shade and cooler temperatures? Such a structure would have to hold up under 80 mph winds and heavy wet snows, and would have to retract in the winter to let in light. Trees provide these values and much more, giving off oxygen, providing housing for birds, and protection for understory plants. Thus it is very important to take good care of our trees, and the most fundamental level of that care must be directed to the roots.[Read More]

Biological Farming and Gardening

A New Model for the 21st Century

A newer science that is not tied to petroleum profits is emerging to challenge the industrial approach to agriculture and gardening. Of course, the enormously powerful and politically connected corporate giants like Monsanto, Bayer and Dupont will continue to make money, but after 60 years of dominance, the “Better Living Through Chemistry” model can no longer hide its fatal flaws. Mountains of evidence now point to the effects of chemical agriculture: poisoning the earth, driving global climate change, causing major health problems, killing pollinators and destroying the life of the soil. The good news is that a more long-range, wholistic view is starting to take its place. This new approach is being called Biological Agriculture and Gardening.[Read More]

Biological Thinking

It has been suggested that this period of the 21st Century might well be called The Age of Biology, because the biggest challenges will be biological and the biggest breakthroughs will be in the realm of biology.

In this article, we will continue the discussion from the last issue on Biological Agriculture and Gardening, but this time going into specifics of biological thinking, biological discoveries and applications that improve plant and food success with biological solutions.[Read More]

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

Food Safety and GMOs

Food safety is one of the most critical issues of our time. What we eat is directly related to our health, and health care has a direct impact on our personal and national economies. Major chemical companies like Monsanto, Bayer, Dow and Dupont have introduced 86,000 synthetic chemicals into our environment, food, drugs, cosmetics etc and most of them have never been tested for toxic effects on human health and the environment. Since the mid 1990s, some of these same companies have been filling our grocery stores and feed stores with genetically engineered food products which may be causing serious health problems but are being approved by our government without safety testing.[Read More]

Gardening from the Heart

Most of us were taught that gardening is about control, about battling unruly, ravenous nature to succeed with our objectives. And a very complex and prosperous industry sprang up in the late 1940s to provide us with the power and weapons to meet those expectations. Petroleum products from World War II chemical weapons, defoliants and bombs were reformulated to solve our plant problems and feed the world. These chemical fertilizers, pesticides and herbicides have now had 50-60 years to show that this aggressive, heartless and poisonous approach has failed. Foods with little nutritional value and a polluted world are inspiring a strong international movement toward sustainability.[Read More]

Columbines in Colorado

Everybody seems to love columbines with their delicate, exquisite beauty, both elegant and elusive. The Rocky Mt. Columbine is the state flower of Colorado and yet we seldom, if ever, see front yards swaying with masses of their classic loveliness. What is the story or trick to growing these plants successfully in Colorado? Because of my own mixed success with columbines, I decided for this article, to add the experience of other gardeners to my personal views.[Read More]

Gardening without Chemicals

How can we deal with all the bugs and diseases without using toxic poisons, and how can our gardens really produce without high-powered chemical fertilizers? Many people wanting to garden sustainably are asking these questions. And it is not easy to find the answers, partly because the answers are not simple. I want to admit this up front, but don’t be scared off, because it’s not that hard to garden sustainably once you get the hang of it. However you must know that you can’t just exchange a slam-bam chemical approach for a slam-bam sustainable approach.[Read More]

Gardening Without Fear

The key to minimal maintenance and a low input approach is Gardening Without Fear. The solution to gardening without fear is twofold: being empowered to garden successfully and being relaxed and tolerant. If we are fearful, we will react to every little problem, worry and criticize ourselves. Then we might seek an immediate solution like some poison.

We have been guided to believe that we need these petroleum products by companies that sell them. In fact, these products weaken the support systems of plants and make them more vulnerable to diseases, pests and drought. The truth is—we don’t need them.[Read More]

Invasive Plants and Weed Profiles

Last month we raised the issue of invasive introduced plants and the idea of being responsible gardeners who respect our native habitat and make an effort to not release invasive plants into the wild. We began with obvious noxious weeds that are having strong negative impacts on our native populations of plants and animals. This month again I am profiling weeds which have been declared as noxious, but this time a question is beginning to arise about under what circumstances are some of the less aggressive weeds invasive? In other words, is it possible that we might find a middle way that guides us strictly with the truly harmful invasives and more leniently with the less aggressive and more useful weedy plants? These are questions I am asking myself and will be asking in future interviews. We also welcome your views on this issue.[Read More]

Invasives August Issue

In February 2000 President Clinton established the National Invasive Species Council. Agriculture secretary Dan Glickman, Commerce Secretary William Daley and Interior Secretary Bruce Babbitt were asked to work together on a plan to minimize the economic, ecological and human health impact of invasive plants and animals not native to the US. The executive order on Invasive Species directs federal agencies to prevent the introduction of invasive species, to control populations of such species in a cost-effective and environmentally sound manner, to monitor populations, restore native species, conduct research and promote public education on invasive species.[Read More]

Invasives Intro

One of the hot subjects in horticulture these days is the issue of the invasiveness of introduced plants. Since they did not evolve here, they lack natural enemies, and whereas most are harmless, some have engulfed vast areas of wilderness, national forests, range and farm lands. This has led some people to campaign for “natives only” and others to attack the introduction of new plants as an ecological nightmare. In response to these attacks some in the plant industry have dismissed these fears as invalid over-reactions. As Colorado gardeners, most of us can be both excited by new plant introductions that are well-adapted to Colorado conditions, and feel very protective of our natural ecosystem and our native plants. In a series of articles, we hope to uncover some truths regarding these issues and to educate ourselves about how to work with this situation in a constructive manner.[Read More]

Nitrous Oxide

The forgotton greenhouse gas and how it relates to growing plants

Nitrogen is one of the most essential nutrients for plants. Nitrogen is required for building amino acids, DNA and RNA, in stimulating growth, supporting health and is a critical ingredient in chlorophyll, the chemical needed for photosynthesis. In our gardens, when nitrogen is lacking, plants are small and yellow, and roots do not perform well. In Colorado, almost all our soils are deficient in nitrogen and organic matter. So we gardeners often add fertilizers and composts to our soils.[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. Your best chances of establishing a tree during water restrictions are to:[Read More]

Pea-Planting Advice

Local advice from our friend Elizabeth:

Hi All, I have been trying a new technique (at least for me) of starting peas in sections of guttering (which I got at Resource) in the greenhouse, growing them on until they are about 4 inches tall, and then transferring them to a trench in the garden.  So far it seems to be working fairly well. The peas germinate really fast and grow quickly in the greenhouse. You could probably do it in a house too. I plug up the ends of the guttering with a piece of foam and duct tape. When I am ready to transfer them, I dig a trench, remove the foam and duct tape, spread the sides of the guttering away from the soil, and slide them out of the guttering into the trench. The sliding is the tricky part.  I have found it takes two people to go well: one to guide and encourage the peas along, and one to lift and shake the guttering, as you have to get it to a fairly steep angle for the peas to slide. I’m using galvanized guttering, but plastic might work better as it would be smoother.  So far they have adapted well to the outdoors, and we shall see how they grow on and produce. There’s lots of videos of this on the web. Thought this might be a good solution to slow germination in our really unpredictable springs.

[Read More]

Bees, Beauty, and Biodiversity

It used to be that beauty was enough. If the lawn looked good and we had a few shrubs and a few flowers, we could relax, having done our duty to the neighborhood.

Now we have to be water-wise, save the bees and the Monarch Butterflies, and on top of that, we’ve got to have Biodiversity.

I think this is a good trend. Gardens are more than something to look at. They are a piece of Nature and the more diverse they are, the more like Nature they are.[Read More]

Canadian Roses for Colorado

The Canadians, like their English and French ancestors, have a great love of roses. However much of Canada is in zones 4, 3 and even zone 2. Therefore many of the hybrid tea and floribunda roses bred in modern times have not been tough enough for Canadian gardeners. So the Canadians set their own federal agriculture department to work on breeding roses that succeed in Canada. Not only do these roses do well north of our border, they are very successful in Colorado, even in our higher elevation environments. Our 10-20 below zero winters and dramatic temperature changes can kill or significantly injure more tender roses like the hybrid teas and floribundas. So gardeners in Colorado who don’t have time to remove large masses of dead canes, hill soil around the canes to protect them for winter, and who have less inclination to spray and fertilize frequently, find the Canadian-bred roses provide a rewarding and easy-care alternative.[Read More]

Difficult Broadleaf Evergreens for Colorado

In the last issue I discussed the easy broadleaf evergreens for Colorado and this time we will go into the difficult ones. Many people have killed or had poor success with rhododendrons, hollies, azaleas and daphnes etc. so it is good to understand these plants further. Unfortunately in my sunny, low-water gardens, I have had little experience with them so I went to two people who have plenty of experience, Don Zaun and Allan Taylor.[Read More]

Feed the Soil, Not the Plant

It is widely known that nitrogen is essential for plants. It is a major component of amino acids, DNA and chlorophyll. It is necessary for photosynthesis, the alchemical process of turning sunlight, carbon dioxide, minerals and water into oxygen and sugars that is the food that feeds life on earth. In Colorado, most of our soils are deficient in nitrogen.

But too much nitrogen can be a problem, especially high nitrogen chemical fertilizers. Bill McKibben, author of The Art of Balancing Soil Nutrients states, “Although all plant nutrients are critical, none seem to produce such quick and dramatic effect on plant growth as nitrogen does. It is because of this reason that nitrogen has been over-used and abused.” A 20%-30% nitrogen fertilizer can make a spring lawn turn bright green practically overnight, and can make plants in a greenhouse or garden grow and look mature really fast. So what’s the problem?[Read More]

Flood Recovery for the Garden

Flood recovery is not a problem most of us have had to deal with before so we can only try to solve the problems individually and make adjustments in the future.

The main problems seem to be:

1) Soil washed away-erosion

2) Soil dumped on top of plants, trees and existing soil

3) Plants washed away

4) Weed seeds deposited on the soil 5) manure and sewage and unknown contaminants deposited on the land[Read More]

Easy Broadleaf Evergreens for Colorado

In the winter when the deciduous plants have dropped their leaves, the evergreens really stand out. If we go for a walk, especially in the older neighborhoods, what evergreens do we see? The greatest numbers are spruces, firs, pines and junipers. In general these conifers with their narrow needles or scales are adapted to our cold temperatures, strong winds and sunny winter days. But there are other woody evergreens to be seen in Colorado neighborhoods: the broad-leaf evergreens. In general their wide leaves transpire more and are more prone to desiccation in our drying conditions; however by choosing the right plants and siting them in their right places, we can enjoy these less popular but deeply satisfying winter-green shrubs and vines. In this article I will discuss the easy broad-leaf evergreens for Colorado and in the April issue we will talk about the difficult ones.[Read More]