Harlequins Gardens

Boulder's specialist in well-adapted plants

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Natives We Often Have for Sale

These are native plants that we often have for sale. Availability does change every year, but we grow and buy a wide variety of natives because they are so successful in our gardens.

KEY: t = tree, s = shrub, v = vine, gr = grass, gc = ground cover, p = perennial,

b = biennial, a = annual

Abronia fragrans (Sand Verbena) (p)

Acer glabrum (Rocky Mt. Maple) (t)

Acer grandidentatum (Bigtooth Maple) (t)

Achillea lanulosa (Native White Yarrow) (p)

Agastache cana (Hummingbird Mint) (p)

Agave parryi (Hardy Century Plant) (s)[Read More]

Native Plants In Harlequin’s Gardens Display Gardens

Achillea lanulosa (Achillea millefolium var. lanulosa) (Yarrow)

Agave havardii (Havard’s Century Plant)

Agave parryi neomexicana (New Mexico Century Plant)

Amelanchier alnifolia (Serviceberry)

Amorpha canescens (Leadplant)

Amorpha fruticosa (False Indigo)

Amorpha nana (Dwarf Leadplant)

Amsonia jonesii (Jones’ Bluestar)

Andropogon gerardii ëPawnee’ (Pawnee Big Bluestem)

Andropogon saccharoides (Silver Beard Grass)

Aquilegia barnebyi (Barneby’s Columbine)

Aquilegia caerulea (Rocky Mt. Columbine)

Aquilegia chrysantha (Yellow Columbine)

Arenaria hookeri (Sandwort)

Argemone polyanthemos (Prickly Poppy)

Artemisia campestris (Wild Tarragon)

Artemisia filifolia (Sand Sage)

Artemisia frigida (Fringed Sage, Silver Sage )

Artemisia ludoviciana (Silver King Artemisia)

Artemisia nova (Black Sage)

Artemisia tridentata syn. Seriphidium tridentatum (Western Big Sage)

Artemisia tripartita(Cutleaf Big Sage)

Aster ericoides (Wreath Aster)

Aster fendleri ëMy Antonia’ (ëMy Antonia’ Rock Aster)

Aster obligifolius (Aromatic Aster)

Aster sericeus (Silky Aster)

Atriplex canescens (Four-wing Saltbrush)

Atriplex confertifolia (Spring Saltbrush)

Baptisia australis minor (Dwarf False Blue Indigo)

Blepharoneuron tricholepis (Pine Dropseed)

Bouteloua curtipendula (Side Oats Grama)

Bouteloua gracilis (Blue Gramma)

Callirhoe involucrata (Wine Cups)

Calylophus serrulatus (Sundrops)

Ceanothus fendleri (Buckbrush)

Cerastium arvense (Field Mouse Ear)

Ceratoides lanata (Winterfat)

Cercocarpus intricatus (Dwarf Mountain Mahogany)

Cercocarpus ledifolius (Curl-leaf Mountain Mahogany)

Cercocarpus montana (Mountain Mahogany)

Chamaebataria millefolium (Fernbush)

Chilopsis linearis (Desert Willow)

Chrysothamnus nauseosus nauseosus (Dwarf Rabbitbrush)

Clematis ligusticifolia (Western Virgin’s Bower)

Coryphantha missouriensis

Crataegus douglasii (Douglas Hawthorn)

Cupressus arizonica (Arizona Cypress)

Cylindropuntia imbricata (Cholla, Candelabra Cactus)

Cylindropuntia whipplei (Whipple’s Cholla)

Datura wrightii (D. meteloides) (Sacred Datura)

Echinacea tennesseensis (Tennessee Coneflower)

Echinocereus caespitosus

Echinocereus reichenbachii (Lace Cactus)

Echinocereus triglochidiatus (Claret Cup Cactus)

Echinocereus viridiflorus

Eragrostis trichodes (Sand Love Grass)

Erigeron flagellaris (Whiplash Daisy)

Eriogonum heracleifolium

Eriogonum jamesii flavescens

Eriogonum niveum niveum

Eriogonum ovalifolium

Eriogonum umbellatum (Sulphur Flower)

Eriogonum umbellatum ëKannah Creek’

Eriogonum umbellatum subalpinum

Eriogonum wrightii wrightii (Wright’s Sulfur Flower)

Escobari vivapara

Fallugia paradoxa (Apache Plume)

Fendlera rupicola (Cliff Fendler Bush)

Forestiera neo-mexicana (New Mexican Privet)

Gaillardia aristata (Indian Blanket Flower)

Geranium fremontii (Fremont Geranium)

Geranium richardsonii (Richardson Geranium)

Gilia aggregata (Scarlet Gilia)

Gutierrezia sarothrae (Snake Weed)

Helianthus pumilus (Dwarf Sunflower)

Hesperaloe parviflora (Texas Red Yucca)

Humulus lupulus neomexicana (Wild Hop Vine)

Hymenoxys scaposa (Perky Sue)

Juniperus monosperma (Single-seed Juniper)

Juniperus scopulorum (Rocky Mt. Juniper)

Leucocrinum montanum (Sand Lily)

Liatris punctata (Gayfeather, Blazing Star)

Linum lewisii (Native Blue Flax)

Lithospermum multiflorum (Many-flowered Pucoon)

Lomatium orientale (Native Parsley)

Mahonia fremontii (Fremont’s Mahonia)

Mentzelia decapetala (Blazing Star)

Mirabilis multiflora (Desert Four-O’Clock)

Nolina microcarpa (Beargrass)

Oenothera caespitosa (Tufted Evening Primrose)

Oenothera howardii (Howard’s Evening Primrose)

Oenothera mac. Incana ëSilver Blade’

Opuntia fragilis (Fragile Prickly Pear)

Opuntia polyacantha (Yellow Prickly Pear)

Oryzopsis hymenoides (Indian Rice Grass)

Oxytropis lambertii (Lambert’s Locoweed)

Panicum virgatum ëShenandoah’ (Red Switchgrass)

Pediocactus simpsonii (Mt. Ball Cactus)

Penstemon alamosensis

Penstemon ambiguous

Penstemon angustifolius

Penstemon arenicola

Penstemon barbatus ëCoccineus’

Penstemon buckleyi

Penstemon cardinalis

Penstemon clutei

Penstemon cyananthus

Penstemon davidsonii

Penstemon gormanii gormanii

Penstemon grandiflorus

Penstemon havardii

Penstemon linarioides coloradoensis

Penstemon mensarum

Penstemon palmeri

Penstemon procerus

Penstemon pseudospectabilis

Penstemon rostriflorus (Bridges Penstemon)

Penstemon secundiflorus (Sidebells Penstemon)

Penstemon strictus (Rocky Mt. Penstemon)

Penstemon teucroides

Penstemon virens

Penstemon virgatus ssp. asa grayii

Pinus edulis (Pinyon Pine)

Pinus ponderosa (Ponderosa Pine)

Populus tremuloides (Quaking Aspen)

Prunus americanus (Wild Plum)

Prunus besseyi (Western Sand Cherry)

Prunus besseyi ëPawnee Buttes’ (Dwarf Sandcherry)

Prunus virginiana (Chokecherry)

Ptelea trifoliata (Wafer Ash, Hop Tree)

Quercus gambelii (Gambel Oak)

Quercus undulata (Wavy Leaf Oak)

Rhus trilobata (Lemonade Bush, Skunkbrush)

Ribes aureum (Golden Currant)

Ribes cereum (Wax Currant)

Ribes odoratum ëCrandall’ (Crandall Clove Currant)

Rosa acicularis (Arctic Rose)

Rosa arkansana

Rosa woodsii (Woods Rose)

Schizachyrium scoparium ‘The Blues’ (Little Bluestem)

Sedum lanceolatum (Lanceleaf Stonecrop)

Senecio spartioides (Grassleaf Senecio)

Shepherdia argentea (Silver Buffaloberry)

Silene regia (Royal Catchfly)

Solidago nana (Dwarf Goldenrod)

Sorghastrum nutans (Indian Grass)

Sphaeralcea coccinea (Cowboy’s Delight; Scarlet Globemallow)

Sphaeralcea incana (Globe Mallow)

Sporobolus airoides (Alkali sacaton)

Sporobolus heterolepis (Prairie Dropseed)

Sporobolus wrightii (Wright’s Sacaton)

Tradescantia occidentalis (Western Spiderwort)

Yucca baccata (Banana Yucca)

Yucca glauca (Narrowleaf Soapweed)

Yucca harrimanii (Dollhouse Yucca)

Ready, Set, Plant!

What a storm we had last week!  With the windy conditions and record-setting low temps, everyone’s gardens looks very different this week and may need some attention.  If you haven’t already, this is a good time to review our blog about garden cleanup. The good news is that soil temperatures have cooled down to the optimal soil temperature for bulb planting, ~50 degrees.  And, our current mild daytime temps and above-freezing nighttime temps are ideal for planting perennials, and still good for planting roses, shrubs and trees. Inoculating with mycorrhizae and attention to fall and winter watering are the keys to success.

Bulb Planting and Tulipa ‘Paul Scherer’

Starting with bulb planting:  Recommended planting depths are to the bottom of the planting hole where the base of the bulb rests.  Planting depth can vary depending on how light or heavy your soil is – plant deeper in light soils, shallower in heavier soils.  (If you’re in doubt, a general rule is that planting depth is 3 times the height of the bulb.) 

You don’t have to dig a single hole for each bulb!  You can dig a large hole, say 8-14″ wide by 16-24″ long, to accommodate a large grouping, or swath of bulbs.  This is a great way to save time, to create a more naturalized look, and to combine two or three types of bulbs in one grouping. 

Single Early, Triumph, Darwin Hybrid, and Multi-flowering tulips should be planted 8″ deep to perform as perennials, and fertilized each year just after bloom. Be sure to allow the leaves and stems to wither naturally before cutting them down.

You may want to sprinkle bone meal in the bottom of the hole so that it can touch the bulb roots.  We love Root Rally, which is a blend of bone meal and Endo/Ecto mycorrhizae spores and plant nutrients, providing mycorrhizae life support for all plants.  (See more on mycorrhizae, below.)  Refill the hole and water well. 

See Eve’s ideas for ways and places to use bulbs that you may not have thought of!

Peruse our complete list of 2019 bulbs and individual images and descriptions 

Monarda didyma ‘Jacob Cline’

Planting perennials, roses, shrubs and trees:  The fall is a great time to plant perennials, roses and shrubs as they can focus solely on root growth instead of trying to reproduce.  After gently removing its pot, gently swish the root ball in a bucket of unchlorinated water with water-soluble mycorrhizae  (let the water sit overnight to release chlorine and add the mycorrhizae later).   Mycorrhizae is a beneficial fungi that attaches to roots, allowing them to better absorb water and nutrients.  This results in faster plant and root growth, and better transplanting success.  If you only have granular mycorrhizae on-hand, sprinkle it on the roots as you are planting.  Read more about mycorrhizae in Mikl’s article, “Mycorrhizae: The Hidden Marriage of Plants and Fungi”.

By gently swishing the root ball in water, the root mass will loose its pot-shape and individual roots will be lengthened.  This allows the ends of the roots to be planted deeper, helping to ensure long-term drought hardiness. 

After late-season planting, be sure to (hand) water deeply and frequently, at least twice a month for woody plants, throughout the winter. 

For specific info on rose planting, see Eve’s rose planting instructions.

Zauschneria garrettii ‘Orange Carpet’

Finally, a quick additional word on garden clean-up.  Some of our Southwestern plants should not yet be cut-back.  Wait until April to do so, which will give them additional time to gather and store nutrients, and keep the crowns of the plants from getting too cold. These plants include, but aren’t limited to, Agastache, Salvia  (S. lemmonii ‘Desert Rose’, S. reptans, S. x microphyllus ‘Royal Ruby’, S. greggii ‘Furman’s Red’, S. darcyi), Zauschneria (Hummingbird Trumpet), Scrophularia macrantha (Red Birds in a Tree), Scutellaria suffrutescens (Cherry Skullcap), Gaura lindheimeri.

Snow Preparation and Protection

With our current mild temperatures, it can be difficult to visualize the forecast 50 degree drop in temperature and snow that await us Wednesday night. But we saw it happen a few years ago and know that our green gardens may become limp puddles of frozen plant material, and that worse, since trees and shrubs have not dropped their foliage yet their branches may break under their weight of the snow.  The good news is that there are a few things you can do to mitigate damage.

SHRUBS and TREES – These in-leaf plants are the most vulnerable to damage as the wet and heavy snow can break their branches.  To help prevent this, knock the snow off the plant periodically.  If possible, do so by knocking the under-side of the branch rather than striking downward on the plant.

SMALL SHRUBS – Valuable, young woody perennials and shrubs, such as Daphne, can be protected by covering with over-turned plant pots to help protect their branches from breaking.

PERENNIALS – Following the snow storm, it’s fine to leave the remaining plant material.

COOL SEASON VEGGIES – To minimize damage, harvest your kale, chard, spinach, etc. as desired, then cover the remaining in-ground plant with a couple layers of Ensulate Row Cover fabric.  Large over-turned plant pots, stuffed with bubble-wrap will suffice as well. The snow on top of the fabric and/or pots will also help to insulate the plant.  We have used plant pots are available for sale at low prices.

 

 

 

 

 

TOMATOES – If your tomato plants are still bearing fruit, pull the tomato plant and it’s roots out of the ground and hang it upside-down in a frost-free place such as a heated garage, where much of the fruit should continue to ripen. If this isn’t possible, harvest your fruit and let it ripen on a window sill.  So long as the tomato is showing some lightening of the green flesh to pale green or white, it will likely ripen.

 

Bulb Tips from Eve

Species Crocus are the earliest Crocus to flower, at least two weeks before their Large Flowering siblings, and are the best for early spring lawn tapestries: hold off mowing the lawn until the foliage has died back. Drifts are also lovely in garden borders and rock gardens. Plant 4” deep and 3”- 4” apart, about nine bulbs per square foot for a dense planting. (Crocus are also good for forcing indoors over the winter. Pot them up in mid-October and pre-cool them at a consistent, dark 38 to 45 degrees F for eight to ten weeks with moderate watering. Bring them into the house ~ they will bloom about four weeks later.)

 

Narcissus (Daffodil) Culture

Narcissus are easily grown in average, medium, well-drained soil in full sun to part shade. Best in organically rich, sandy to loams that drain well. Plant bulbs 4-6″ deep and 3-6” apart in fall. After the flowers have bloomed, the top portion of each flower stem may be removed, as practicable, to prevent seed formation, but foliage should not be cut back until it begins to yellow. Flowers usually face the sun, so bulbs should be grown with any shade areas at the rear of the planting. Bulbs can be left undisturbed for a number of years.

Xeriscape: Native 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]

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]

Hyacinth ‘Aiolos’

 Dense columns of waxy, pure white florets appear in mid-spring on sturdy stems. Aiolos has an intense, sweet fragrance and is a long-lasting cut flower. Grows 10” tall. Plant 6” deep and 6” apart. Hardy to zone 3.

Harvest Guidelines for Summer Crops

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]

Narcissus ‘Mount Hood’

Breathtaking pure white flowers. Grows to 14” tall. Plant 6” deep and 6” apart in full sun to light shade. Deer and rabbit resistant. Hardy to zone 3.

Narcissus ‘Spring Pride’ Large Cup Daffodil

‘Spring Pride’ has white petals and a white trumpet with ruffled apricot-pink fringe. The plant will not leaf out until after the Narcissus have bloomed. Deer and rabbit resistant. Plant 8” deep and 6” apart in full sun to light shade. Hardy to zone 3.

Tulipa ‘Lipgloss Stain’ Species Tulip Mix

This mix of species tulips in pastel pinks and greenish-yellows is reminiscent of a watercolor painting. The flowers grow to 8” tall. Plant 6” deep in full to part sun. Hardy to zone 3

Tulipa ‘Little Beauty’ Species Tulip

These adorable Species Tulips have reddish-pink petals with glowing, blue-eyed centers. Plant 3” deep in full to part sun. Lightly fragrant. Grows 4-6” tall. Zone 3.

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]

Planting Instructions for Roses

Planting Container-Grown Own-Root Roses

Thank you for buying your roses at Harlequin’s Gardens nursery! To get off to a good start for growing beautiful, healthy roses, please follow these planting instructions. Please read them through before you begin.

WHEN: Many of our roses have been over-wintered outdoors; these may be planted as soon as your soil can be properly dug and worked. Otherwise, in Colorado’s Front Range region, plant roses after the average “last frost” date (in Boulder,May 15). Roses that have just arrived from greenhouse growers may need to be “hardened off” for 4 to 7 days prior to planting. Keep them outdoors in a place where they’ll be somewhat protected from sun, wind and major temperature changes (you can bring them into a garage or shed temporarily to wait out a late frost or storm). You can plant roses all through the summer, as long as you can keep them watered. And we’ve had great success with fall planting, well into October, with monthly winter watering.[Read More]

Tulipa ‘Pretty Princess’

Tulip ‘Pretty Princess’ is a strain of the Tulip Princess Irene, one of the oldest and most popular tulip varieties ever grown and cultivated in the Netherlannds. Tulip ‘Pretty Princess’ has a soft pink color combined with darker pink flames. The foliage has a pure white edging. Grows to 14” tall. Plant 3” deep in full sun to partial shade. Hardy to zone 3.

Cherry Trees on the Front Range

According to some reports, Colorado weather in 2014-2015 has resulted in the deaths of 80% of our cherry, plum and peach trees. How did this happen? Does it make sense to replant? And if so, how can we reduce future losses and increase fruitful successes? This article will focus on cherry trees.[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]

Eve’s Favorite Fragrant Roses

  • “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!
  • “Broadway Perpetual” (found, Boulder) Z 5 (4?) Large dbl strong pink quartered, deep old-rose perfume, spring & fall, sporadic inbetween. Good cut-flower. Seems somewhat shade-tolerant. Strong arching growth to 7’. Potential climber? Healthy foliage, moderately prickly.
  • “Fairmount Proserpine” (found, Denver)

[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]

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]

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]

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]