This fall, Garden Magazine’s Matt Mcclellan interviewed Mikl to find out more about our sustainable approach to growing plants and how it appeals to our conscientious customers. Read the article here
We Re-Open Nov 20 – Dec 23 for our 14th Annual Holiday Gift Market!
Gift Memberships & Gift Certificates – available online!
See our seasonal hours and address, below.
This fall, Garden Magazine’s Matt Mcclellan interviewed Mikl to find out more about our sustainable approach to growing plants and how it appeals to our conscientious customers. Read the article here

“Every day, millions upon millions of seeds lift their two green wings” (Janisse Ray)
(Okay, if it’s a ‘monocot’, it only lifts one green wing, but we can allow a bit of poetic license)
I love seeds. They’ve fascinated me since early childhood. Some of my earliest memories involve examining maple samaras, sycamore balls, acorns and pine cones, and planting peas and Sweet Alyssum and lima beans in cut-off milk cartons on the kitchen windowsill. I am still in awe of the power packed into a seed. [Read More]
It’s the time of year to ready our gardens for the upcoming fallow winter season and prepare for next year’s growth. We do this knowing that regeneration will be occurring in our soil, with the microbes and with overwintering insects. Here are tips for you to best help this process take place, while still having an aesthetically pleasing garden. [Read More]

Autumn has declared itself on the Front Range, and many gardeners are itching to bring a close to the gardening year by tidying up. But wait! There are some important issues to consider here before bringing out the rakes, blowers, clippers and shears.

Now is a great time to take a long look at your gardens and make notes on successes, disappointments, gaps, and changes that you’d like to make. Assess the ecosystem you have created, and think about how you can make it even more supportive of our precious wildlife, beneficial insects, pollinators and soil life.
A certain amount of garden clean-up is very important for reducing diseases and pests that are difficult to control. If you haven’t already done so, do remove diseased plants from your vegetable garden. You should have been removing and treating diseased foliage from roses or shrubs with fungal diseases like mildew, blackspot or rust before now, but if their disease-carrying foliage is falling now, keep them picked up and dispose of them responsibly.

But don’t be so quick to scalp those perennials and annuals! Many of them provide natural food and shelter sources that wildlife and beneficial insects depend on for winter survival. You may not have noticed, but so many beneficial insects and butterfly larvae spend the winter in the (often hollow) dead stems. If you throw them out, you’ll lose most of the beneficials that would otherwise keep the balance next year. Always keep an eye out for egg cases attached to stalks when you prune or clean up. There’s often an aesthetic side-benefit – many seed-heads look fabulous either crowned with snow or silhouetted against the snow-covered ground.
Some perennials die back to below ground (peonies, false indigo, gas plant, golden banner, balloon flower, desert four o’clock, gayfeather, leadwort/plumbago, etc.) leaving no basal growth and leaving a completely blank space. To make sure you don’t forget where they are and accidentally dig them up or step on them, leave dry stems until the new growth begins to appear in spring.
Unless you have an ‘ornamental’ grass that self-sows aggressively, leave grasses and their seedheads standing. If they are ‘cool-season’ grasses, you’ll want to leave them until about mid-February, then cut them to 3” above the ground so they can begin making unimpeded new growth as soon as the soil thaws. Dormant ‘warm-season’ grasses can remain attractive until warm weather comes and don’t need to be cut down until April.
Leaving dry stalks standing in the winter also helps preserve soil structure. Snow collects between the stalks and provides protection from freezing temperatures by insulation for the crowns of the plants, especially important for marginally hardy plants. Captured snow keeps soil temperature more consistent, protecting from extreme temperature fluctuations, and helps prevent the alternate freezing and thawing that can disrupt mycorrhizal networks (and uproot plants, especially new and small ones).

Leave the leaves! The larvae of many butterflies overwinter in the blanket of autumn leaves, as well as other beneficials. The leaves also provide cover for frogs, toads and spiders. Songbirds eat more than just seeds; they search in the leaf litter for insect eggs and caterpillars. As leaves naturally break down over time, they feed the soil microbes that make nutrients available to plants. Worried about harboring snail and slugs? Before those leaves begin to fall, spread a non-toxic slug bait like Sluggo in areas of concern. You may want to remove leaves and twigs from patios, decks, walkways and lawns, and that’s fine – especially if you can spread them under shrubs or pile them in a corner where they’ll remain undisturbed through the winter. And very large, flat leaves from trees like Catalpa, Basswood (Tilia americana), Norway Maple, Sycamore/London Planetree) should be cleared from beds or they can form a slick solid mat that smothers the crowns of smaller plants.


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]
“On September 20th, young people and adults across the US and world will strike to tell the UN and leaders across the world that we want climate action. By growing and uniting the multi generational climate movement, the strike is the launch of a new era for just and equitable climate action.”
Harlequin’s Gardens is joining the Climate Strike, Friday Sept. 20th, by striking while the iron is hot, increasing the focus on the Climate Crisis.
At Harlequin’s Gardens we will not be leaving our jobs on September 20. Instead we will be at work for Harlequin’s where we are always working to help you and the planet. AND we will be giving away one Free bag of compost with each purchase, on Friday, the 20th.[Read More]
This year’s tomato tasting was a great success, with a total of 41 tomato varieties present over the 3-hour event!
Participants brought in some wonderful new varieties this year, including Pink Bumble Bee Cherry, Gajo de Melon, and Blue Cream Berries. We always take people’s votes into account when deciding which tomato varieties to carry, so look for the most popular varieties from this year and previous years when you come to buy your organic tomato starts next spring at Harlequin’s Gardens. Every year we grow 80+ great varieties for all kinds of uses and growing conditions! A huge thank-you to Growing Gardens for providing our the location, helping us publicize the event, and for bringing us some fabulous volunteers. Thank you also to the volunteers of Slow Food Boulder County. We couldn’t have done it without you!

2019 Taste of Tomato Vote Tally
Whoever heard of Goji Berry 20 years ago? Now, with the current interest in superfoods, phytonutrients and antioxidants, Goji Berry juice and dried fruits can be found in many urban grocery stores. The 70+ species of Lycium are found on most continents and one species, Lycium pallidum, is native to Colorado. But the best known and most grown Goji is Lycium barbarum, the Chinese Wolfberry, also known as Matrimony Vine, Desert Thorn and Boxthorn. What is not commonly known is that this exotic superfood can be easily grown in Colorado.[Read More]
It’s a common idea that Nature, left to its own devices, comes to some kind of balance. If one organism gets too numerous, something else will increase to reduce that population. In the case of monocultures created by humans, there is an enforced imbalance that has to be propped up with lots of energy and effort. So in the pursuit of sustainability, humans are opening our eyes to the possibility of biomimicry, imitating Nature. We are coming to the realization that biodiversity is far healthier and less energy intensive than monocultures born out of the aggressive hubris to control Nature. “Let Nature take her course.” But we can stack the deck in human favor first.[Read More]
A newer science that’s not tied to petroleum profits is emerging to challenge the industrial approach to agriculture and gardening. Enormously powerful, politically connected 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 downside of chemical agriculture: poisoning the earth, driving global climate change, causing major health problems, killing pollinators, destroying the life of the soil. The good news is that a more long-range, wholistic view called Biological Agriculture and Gardening is starting to take its place.
This “new” method is based on an entirely different paradigm or model of plant culture. Instead of the bellicose mentality that birthed the pesticide-fungicide-herbicide and chemical fertilizer approach, the biological approach taps the same cooperative relationships that Nature herself has long employed successfully for survival and sustainability. Instead of seeing bacteria as germs, fungi as diseases, and insects and weeds as pests, the biological model sees Nature as brilliantly creative and diverse, and basically good. The scientific truth is that few insects, bacteria and fungi are harmful; most are beneficial or essential to plant development, plant health, and subsequently for human health.[Read More]
Acantholimon glumaceum
Acantholimon hohenackeri
Acantholimon litwanovii
Achillea ‘Moonshine’
Achillea ageratifolia (Greek Yarrow)[Read More]
Double Poets Daffodil
Bulb. Z3. 16-18” tall. Blooms late spring. Compost-improved soil. Heirloom.
Full, ruffled, snowy-white blooms are a gorgeous, bright beacon in your spring garden. Highly fragrant, so be sure to place them near paths and patios where you can enjoy them. Blooms are most prolific in cool springs. Deer and rabbit resistant. Lovely combined with columbine, Icelandic poppies and bleeding hearts.
Non-toxic Herbicides
Summer is a successful time to kill weeds, either by mechanical weeding or with herbicides. But toxic herbicides, like Roundup are not solutions we recommend. Roundup in particular was once believed to be quite safe, but now is shown to be harmful to soil life including nitrogen-fixing bacteria, amphibians and is a probable human carcinogen. Roundup formulations can be up to 400 times more toxic than the active ingredient, glyphosate.
At Harlequin’s Gardens, we only sell non-toxic products, but not all non-toxic products are actually effective. Four years ago we tested five non-toxic herbicides and found only two to be really effective: 20% Vinegar and Avenger.
20% Vinegar is 20% acetic acid. It is a non-selective organic acid that quickly kills many weeds, then quickly biodegrades. Repeated use can acidify the soil which is usually a benefit in our alkaline soil. Be careful not to spray desirable plants, and be careful to protect your eyes, especially on windy days. It is most effective on small plants. Repeated applications may be necessary on perennial weeds.
Avenger is a citrus oil weed killer that we found to be equally effective as the vinegar. It is certified organic and is biodegradable. Avenger is non-selective so care must be taken to keep spray off desirable plants. It comes in a ready-to-use (RTU) formula and in a concentrate which may be mixed stronger for tougher, perennial weeds. Like vinegar, it is most effective on small plants, and is best sprayed during hot weather in direct sunlight.
In order to “control” bindweed and other weeds with extensive root systems, don’t let new growth get longer than 2″ or the weed will revive.
BLISTER BEETLE: We have been hearing reports of Blister Beetle attacking clematis. This is a light grey, long beetle that can defoliate a clematis vine in 2 or 3 days. We have found that an organic product called Veggie Pharm actually kills this beetle. It must be sprayed directly on the beetle. (Don’t try to pick up a Blister Beetle; they can raise a blister)
Tree Wrap: We recently saw a big buck with his antlers in the velvet stage. This the time of year deer cause the most damage, when bucks rub their itchy antlers on smooth, usually young tree trunk, tearing the bark. Sometimes a young tree can be girdled in one night. We carry a very good spiral plastic tree wrap that protects trees from deer, rabbits, sun scald in winter. It is superior to paper wraps because it lets air circulate so moisture does not decay the bark. It can be left on in the summer and it expands as the tree grows. Once the bark is older and tougher, it will no longer need protection.
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]
This year’s Taste of Tomato was a blast! We love the new location at Growing Gardens’ Barn, with its’ beautiful view of the Flatirons, easy access, and wonderful staff. The tasting featured 44 different varieties of tomatoes, with Aunt Ruby’s German Green winning the greatest number of votes. Participants brought in some wonderful new varieties this year, including Brad’s Atomic Grape, Thornburn’s Terracotta, and Indigo Cherry. Look for the most popular varieties from this year and previous years when you come to buy your organic tomato starts next spring at Harlequin’s Gardens. Every year we grow 80+ great varieties for all kinds of uses and growing conditions![Read More]
Here are a few harvest guidelines for summer crops:
Eggplants should be picked while they are still firm and glossy. Once their skins have become dull, they will be softer and have dark seeds, which can spoil the flavor. Eggplants don’t keep long, so use them soon after harvest.
Bell peppers and sweet frying peppers are sweetest when allowed to ripen fully to their mature color, yellow, orange, red, purple or mahogany. Bell peppers are often picked green, but their flavor will be a lot more pungent and they may be more challenging to digest.
Some of the hot peppers are traditionally enjoyed green – poblano, mulatto, jalapeno, Anaheim-type, while most of the rest are allowed to ripen to red (cherry, habanero, cayenne, lanterna, any chile dried for a ristra, etc.) orange (Bulgarian Carrot), or dark brown (Pasilla).[Read More]
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]
NEW for 2019!
The darkest Triumph tulip, dramatic purple-black with a straight-sided shape. Earlier than ‘Queen of Night’ but a very similar color. Contrasts wonderfully with any color of tulip, whether your garden plan is classic or goth. Triumph tulips perennialize well in the garden if left uncut and fertilized after blooming. 16–18″ tall. Mid Spring blooms, Z3-7
These are among our favorite fragrant roses. While we grow and sell many of these, they are not always ready to be put out for sale, and quantities are always limited! Come by and view our current selection, and check our 2024 Rose list.

Banshee Rose
“Banshee” (found) Z 4, dbl pink 2″ early & long-blooming May-June, rich sweet damask fragrance; large shrub or climber, no die-back, very disease resistant, very tough & tolerant of low water, poor soil, shade, once established. Distinctive matte foliage, fall color- purple, orange. Common in old neighborhoods all along the Front Range.Not terribly prickly. Cut armloads for big fragrant spring bouquets!

Fairmont Proserpine, courtesy High Country Roses
“Fairmount Proserpine” (found, Denver)

Darlow’s Enigma
Darlow’s Enigma (Cl. Hyb. Musk ?) Vigorous large shrub or climber of unknown origin with very disease-resistant, handsome glossy foliage. Small white semidouble flowers in clusters, borne throughout the season , are very sweetly scented. Very shade-tolerant. Zone 4.

Golden Wings
Golden Wings (Shrub) A healthy, vigorous, open shrub to 5-6’ tall and wide, with large, almost single lemon yellow blossoms accented by showy dark red stamens. The petals fade quickly to white in our strong sun. Blooms all season. Keep dead-headed ‘til August , then allow it to form attractive red hips. Hardy to Zone 5, maybe 4.

Morden Sunrise
Morden Sunrise (Canadian Shrub) A compact shrub, to about 3’x3’. Seems pretty tough in our test/display garden. Semi-double flowers open from orange buds, are 2 1/2 to 3″wide and shade from soft, tawny yellow to apricot pink, to orange. Moderately strong Tea rose fragrance is unusual for a Canadian rose, which are generally scentless. Hardy to Zone 3, almost continuous blooming.

Rosa spinosissima
Rosa spinosissima (Scotsbrier) (Species) My favorite species rose, as it perfumes my gardening hours with its strong, very sweet scent – one of the few fragrances that really carry in our dry air. The 4’ tall shrub is shade tolerant, and has very small leaves on gracefully arching canes that are covered with the lovely pure white single blooms for about 2 1/2 weeks in May. Hardy to Zone 3.

Rose de Rescht
Rose de Rescht (Portland or Damask Perpetual) A very distictive Old Rose, supposedly discovered in Iran. The flowers are small, 1 1/2″ or slightly larger, rich fuschia-red with strong purple tints, aging to magenta, very double, tightly formed rosettes, almost pom-poms, produced in small clusters amid lots of foliage. Exceptional strong Damask fragrance. Excellent repeat. The shrub is healthy, compact and bushy, to 4-5’ tall and wide. Canes are quite prickly. Hardy to Zone 4.

Sharifa Asma
Sharifa Asma (English) Slow to establish, but worth the wait. Blooms are large, double, delicate shell pink, cupped, and blessed with a strong Old-rose and fruity (litchi) fragrance. Leaves are dark green, slightly leathery, and healthy as long as the shrub is not in too much shade. Growth is upright to 4’.
Some fragrant roses to try at higher elevations:
Alba Semi-plena
Alba Suaveolens
Maiden’s Blush
Chloris
Konigen von Danemark
Rosa spinosissima
Rosa rugosa alba
Rosa rugosa ‘Magnifica’
Metis
Banshee
Gallica roses
Centifolia roses
Therese Bugnet
Morden Sunrise
Rugosa roses
In this article, Mikl explains why Soil Health matters.
From Peak Soil to Soil Revolution
We are having a real revolution in our relationship with our soils. The turning point is our change in focus from soil fertility to soil health. In the last 60 years of the “Green Revolution” (i.e. the petrochemical boom), soil was viewed as a physical structure and fertility was viewed as a measure of chemicals in the soil — primarily NPK, nitrogen, phosphorus and potassium. The petroleum industry could make these macronutrients from natural gas, which make plants grow but often in poor health. Weak plants attract insect pests and fungal diseases, so more petroleum in the forms of insecticides and fungicides added to the success of the oil industry. But this approach has led to “Peak Soil” where land is losing productivity, crops are losing nutritional value, the soil is eroding at extreme rates, and the health of animals and people has declined.[Read More]
Colorado is said to be the worst state in the US for fireblight, and 2018 was considered by many to be one of the worst years in Colorado. Fireblight is a serious disease affecting apples, crabapples, pears, Mountain Ash and hawthorn, and sometimes quince and pyracantha (supposedly up to 73 species of plants).[Read More]
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]
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]
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]
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]
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]
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]
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]
Xeriscape Perennials Thriving in 2002 Drought
Acantholimon glumacium
Acantholimon hohenackeri
Acantholimon litwanovii
Achillea ‘Moonshine’
Achillea ageratifolia (Greek Yarrow)[Read More]
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, 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—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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]
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]

Pestemon x. mex ‘Red Rocks’
Despite the heat, July blooms are glorious! At Harlequin’s Gardens we’re often asked to help identify July blooming plants and to provide suggestions for summer blooms. With that in mind, we’ve put together a thorough list of What’s Blooming in July. See what will inspire you!
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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 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]
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]
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]
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]
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]
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