Sticks & Stones – Page 20 – News & Views from Christensen's Plant Center

Boxwood Blight

Boxwood Blight leaf symptoms

You may have heard of a new fungus that has been damaging and killing boxwood in the US. It was first identified in Connecticut in 2011. Called Boxwood Blight, it has now been seen as near as Ohio. It has been predicted that it will continue to spread. Spores can be transferred by physical contact, splashing water, or wind.

Christensen’s Plant Center is taking the necessary steps to make sure that we have clean boxwood in stock for you at all times. This means following the best practices that have come from growers and distributors across the country.

Boxwood

Boxwood Blight is easily transferred by physical contact. Even brushing up against an infected plant means that you can transfer the fungus onto other plants later that day. To that end we must ask that you observe the following when visiting Christensen’s Plant Center.

  • Please do not bring Boxwood plants or parts of a Boxwood into CPC. We will continue to do our best to identify any plant material via a photograph, but we can not have possibly infectious plants brought into our clean nursery.
  • We will no longer accept any returns of Boxwood for any reason. Again, we cannot accept materials back once they have left our clean environment.

These practices are for your success as well as our own. Maintaining a clean facility ensures that we will be able to provide you with material that is free of Boxwood Blight for all of your projects now and in the future. Thank you for your help!

Boxwood Blight ID

Click image for larger size

In the links below are PDFs with more information about this disease.

MSU Extension - Boxwood Blight Disease in North America (2.33 MB)

CAES - Boxwood Blight - A new disease for Connecticut and the U.S. (1.05 MB)

“Jupiters & Yous”

Juniper berries

Guess what! We sell these! I don’t care how you say ‘em or spell ‘em as long as your check clears. I’m pretty sure my boss would agree with me. Hardly a day goes by that we don’t get contractor lists of hybridized and spell-’em-as-you-hear-’em names. I personally love the challenge! And yes, we do sell junipers - and yews.

In particular, Christensen’s sells a number of species of upright Junipers, the Eastern Redcedar. They are somewhat interchangeable with Arborvitae. Junipers require and tolerate hot, dry, sunny conditions but can have difficulties in poorly drained areas. They can be planted as backdrop accent evergreens or hedged into a living fence. A caveat is to avoid planting them too close to some members of the Rose family such as Crabs, Pears, Hawthorn, and Quince due to host/parasite rust occurrences.

The species of Juniperus that Christensen’s typically stocks are:

J. virginiana

  • ‘Keteleer’ - a soft, green needle with loose habit; often used for native plantings
  • ‘Taylor’ - a newer introduction with a bluish-green, tight habit; similar in form to Thuja occ. ‘Emerald Green’

J. chinensis

  • ‘Blue Point’ - a bluish-green, full habit; often used for topiary
  • ‘Hetz Columnaris’ - green needles with broad, architectual habit; best of the fruiting varieties we stock
  • ‘Spartan’ - a green needled variey with a tight, upright habit
Juniper 'Hetz Columnaris'

Juniperus chinensis 'Hetzii Columnaris'

J. scopulorum (Rocky Mountain Junipers)

  • ‘Blue Arrow’ - a soft, bluish upright with a very tight form
  • ‘Skyrocket’ -a grayish, green variey similar in form to ‘Blue Arrow’
  • ‘Wichita Blue’ - a broad, very blue form with very soft growth, but a rugged look
Juniper 'Wichita Blue'

Juniperus scopulorum 'Wichita Blue'

Availability for this genus is not quite as reliable as Arborvitae. We usually see periodic waves of uprights appear throughout the season. Junipers do, however, offer a greater range of color when compared to Arborvitae.

Next time you need an upright evergreen, ask to see some of the varieties just mentioned. Exact spelling not required!

Jeff Good

Mid-season fertilizing

Should I be fertilizing my trees and shrubs in August?

Ask five experts that question and be prepared for five different answers, at least that happened to me. Regardless of the type or size of your new landscape, maintenance will be required to ensure it stays healthy and looking the way it was designed to look. Although 95% of all problems with new plant material can be attributed to improper watering, fertilizers are going to play a big part in getting things established and staying healthy.

Early spring and late fall are obviously your major fertilizing moments, but let's look at right now. New plantings will be aided by the use of some starter fertilizer, especially at new housing and businesses where a lot of good soil has been stripped away. Some cities have poor soil to begin with, lacking nutrients to give plants a good start. We carry some great organic starter fertilizer containing bacteria and mycorrhizae to increase root mass and help avoid transplant loss due to difficult conditions. Light application of these starters and plenty of water will be key during this month.

Fertilizing established plants in August is a little tricky. To avoid stressing the plant, avoid fertilizing during drought or heatwave conditions. Know your soil and fertilize only when plants are truly nutrient deficient. Why? Because new growth forced by fertilizing during this period may not harden off before the onset of winter resulting in tip dieback that won't show until next spring sometime. That's a phone call you won't want to get!

Come by our store and we will help you choose the best product for your particular situation.

Fresh landscaping
Jim Guy

Our free brick samples can head off problems

Brick samples

I love going to Costco on Saturday mornings. Down almost every aisle you’ll find somebody doling out samples, whether it be a tasty snack, a new beverage or an amazing cleaning product. I’ve even had someone showing me how soft their pillows are. I’ve learned to go only after I’ve eaten a large breakfast, and to leave my credit cards at home. If not, I’m often left wondering how I can fit $500 worth of food in my vehicle, in my fridge and in my belly!

Unilock bricks

Sampling is a great selling technique, but an even better tool. Customers will look at a catalog and find the perfect color, only to later find that it may look different in person. Like every other catalog, brick catalogs are carefully photographed and edited. The product you receive may be a slightly different shade, or have a blend of colors you may not have noticed. A few sample pieces that you can take to the site is a great way to see how it will work in your project.

Unilock products

At Christensen’s Hardscape Center, we will gladly sample out most of the products we stock. The exceptions are large items such as steps that require more than a single person to manage. However we can likely match the color with a similar product in a more manageable size. We can also get samples of products that we don’t have in the yard such as those from Fendt, Oaks, or Belgard. We work closely with our vendors, and they are happy to bring us samples upon request. It may take a few days depending on what you are looking for.

Rosetta pavers

As a wholesaler, we do not sell to or give out samples to the general public. Your customers may come in for samples, but we ask that you please call us in advance so we know who they are and that they are legitimately working with you. Samples are free and do not need to be returned. We do request everyone who is looking for samples to please visit us in the showroom first so we can assist you in picking up what you need. Our yard is large and busy, and I don’t want anyone getting a sample of an accident.

Bryan Pajak

Why is my blue spruce turning green?

Picea pungens 'Glauca'

Colorado blue spruce is one of the most popular evergreens we sell. The straight species is usually green, but the cultivar 'Glauca' ranges from bluish-green to an eye-popping silvery blue. The color is genetically determined and before grafting ornamental trees became the norm, the brightest blue seedlings were known as "shiners" and were selected out and sold at a premium. Now we have numerous cultivars with consistent, bright blue color. 

Picea pungens 'Glauca'

So why might you get calls from customers complaining that their expensive blue tree is turning green? Firstly, the blue color is only present on the new growth, weathering off in time. Pesticides can strip off this waxy blue coating from the needles as well. Other culprits can be air pollution, or poor growing conditions that keep new foliage to a minimum.

Picea pungens 'Glauca'

Once the blue color has worn off the needle, nothing will bring it back and the tree is going to look green until that flush of new growth each spring. However, you can encourage the best possible color by providing ideal growing conditions and care. Spruce prefer moist, well-drained soil, and you may fertilize established trees in early fall or mid-spring.

Picea pungens 'Glauca'
Holly Christensen

So you want blue in the garden!

Ceratostigma

Horticulturally speaking, the color blue is rare. So rare, that many of the flowers we call "blue" are in fact... purple. Blue iris? Purple. Blue roses? HA! Purple - and weak at that. Syringa, Campanula, Lobelia, Hyacinth, Baptisia... all have varieties CALLED blue, but they are... purple. I found this quite confusing when I started in the nursery business. Apparently we gardeners are DESPERATE for blue in the garden and we will call anything close "blue".

Picea pungens 'Glauca Globosa'

Picea pungens 'Glauca Globosa'

This tendency extends to foliage as well - blue spruce, blue juniper, and blue hosta, are all rather more silvery than blue, with the added insult of the color wearing off with weather and time! I still chuckle about the customer I had on the retail lot one day, who accused us of spray-painting the 'Moerheim' spruce because, "Look! It rubs off!" There wasn't much I could say because he was right, it did.

Scilla and Chionodoxa

L: Scilla siberica - R: Chionodoxa luciliae

There ARE a few truly blue flowers we can grow in Michigan. Amsonia, Delphinium, Virginia Bluebells, the annual 'Black and Blue' Salvia, Forget-me-nots, Sisyrinchium, and Ceratostigma all have excellent blue flowers. Scilla siberica is a minor bulb that naturalizes and can give you an ocean of blue flowers every spring. Chionodoxa's pretty good, too.

Caryopteris

Caryopteris x clandonensis

In shrubs you can try Caryopteris - wait, that one's a bit on the purple side - heck, it's barely a shrub, more like a woody perennial. Hmmmm. Hibiscus 'Blue Chiffon' is pretty blue. Almost. OKAY, OKAY, FINE. You want blue? You'd best be planting Hydrangea. The old favorite, 'Nikko Blue' has been surpassed by newer cultivars like Nantucket Blue™ and The Endless Summer® line, with the original Endless Summer®, Twist-n-Shout®, and BloomStruck®  all of which bloom on both old and new wood. These plants can be coaxed into producing nice blue blooms with the proper soil pH.

Hydrangea

Hydrangea Endless Summer®

So you do have some options. And take those photos of bright blue-flowering plants on Pinterest with a grain of salt. Most of them are Photoshop. Or perhaps dyed like those poor Phalenopsis orchids at the grocery store. 

Myosotis

Myosotis palustris

Holly Christensen

How to shear boxwood and yew

Sheared taxus

People are always asking me about the best time to prune the shrubs they've installed or are maintaining.  For flowering shrubs the answer is easy - prune right after they’re done blooming. Late pruning in this case is bad since you’re removing the next season's flower buds and most of your clients would not be happy about that.

Buxus ready for next shear

Boxwood (Buxus) and yew (Taxus) are a little different as flowers are not necessary or desired. First and foremost, always use very sharp pruners or shears, to make the pruning easier and reduce damage to the plant. To maintain trimmed forms and hedges you ideally need to shear twice a year. Once in late May or early June after the initial foliar flush, and then a second time around August. This causes the formation of lateral buds which help maintain denser growth. 

Sheared buxus

Keep in mind that shearing a plant to the same exact size every year causes the outside of the plant to become very dense, leaving the interior bare. Allowing for a slight increase helps delay the need for an extreme renewal pruning or plant replacement. Try not to prune during a drought period, and to prevent foliar freezeback pruning should never occur in late fall or winter. If you’re only going to shear once a year, try to do it around August. 

taxus with tight shear

When shearing hedges, taper them so that the top is narrower than the bottom, so all sides will be exposed to sunlight. This will give you a slightly pyramidal shape. Avoid at all cost the inverted pyramid look, as this even further screens sunlight and eventually kills the bottom.

Taxus hedge

Both boxwood and yew are very tolerant of shearing and with proper technique will remain attractive and functional in the landscape for many years. 

sheared taxus
Bill Ten Eyck

Are native plants always better?

amelanchier berries

Native plants have their place in landscaping. It is in native areas. Attempting to force native plants into landscapes in urban areas is difficult for everyone and everything. The plants will have a difficult time being successful in those conditions, and often the property owner and the landscape contractor are not prepared for the amount of maintenance it will take to make this successful. And neither are prepared for the financial commitment to make this successful.

For the last several years there has seemed to be a push to have more natives included in landscapes. To say that I am not a fan of this is not a secret. But it is always nice when someone with Ph.D after their name supports your position. Please read the below article by Dr. Linda Chalker-Scott about how native plants might not be good choice for most landscapes in urban areas.

Aronia melanocarpa

Black Chokeberry  (Aronia melanocarpa) a Michigan native

The Myth of Native Plant Superiority:

"Always choose native plants for environmentally sustainable landscaping."

by Linda Chalker-Scott, Ph.D.

Extension Horticulturist and Associate Professor
Puyallup Research and Extension Center
Washington State University

The Myth

In recent years, people have become more interested in native plants and landscapes as natural ecosystems continue to shrink. This admirable dedication to our natural world heritage has manifested itself in native gardens springing up in every place imaginable. At the same time, I see more of these native gardens suffering from disease, pests, and general decline. What’s happening? Aren’t native plants supposed to be resistant to local pathogens and parasites?

The Reality

There are some urban areas where many native plants just do not survive (or do so only with substantial maintenance). Such areas can include parking strips, traffic circles, and parking lots: in short, areas with limited soil area and a lot of environmental stress. Consider the realities of these landscapes:

  • Discontinuous, dissimilar layers of topsoils and subsoils with poor drainage and aeration
  • Significant compaction and other physical disturbances as a result of animal, pedestrian, and vehicular traffic
  • Alkaline pH due to leaching of lime from concrete
  • Inadequate or improper fertilizer application
  • Lack of mulch or other soil protection
  • Lack of adequate water in summer months
  • Increased heat load from asphalt reflectance
  • Air pollution

Many of the trees and shrubs native to our region evolved in thin, acidic soils with adequate moisture to maintain soil and plant water status. When these species are installed in urban landscapes with significantly different soil and water characteristics they are challenged by a new set of environmental circumstances. As landscape plantings begin to suffer from multiple stresses, they become prone to invasion from opportunistic insects, bacteria, and fungi. Stress can weaken a plant’s natural resistance to local pests; witness the recent decline in our native Arbutus menziesii (Madrone) populations.  

Arbutus_menziesii

Another example of the failure of native trees to survive in urban sites comes from Palm Desert, CA. Many of the parking lots there were planted in native mesquite. Mesquite survives in its arid environment by developing both a deep taproot and an extensive shallow root system. When planted into the very limited soil spaces typical of parking lot tree wells, these trees often tilt or topple as a result of insufficient lateral root development.  The City of Palm Desert has recently looked to non-native tree species, including ash, to replace mesquite in these settings.  

The Bottom Line

  • Native, temperate forest plants are excellent choices for unrestricted sites with acidic, well-drained soils.
  • For sites with limited, alkaline, and/or poorly drained soils, choose species adapted to environments with similar soils. Consider especially those species that tolerate clay soils.
  • For sites exposed to increased heat load, choose species adapted to hot, dry climates that can also tolerate cool, wet winters.
  • Instead of installing large trees into limited sites, consider smaller trees or shrubs that can be arborized.
  • Be sure to protect soils with mulch, especially where foot traffic causes compaction.
  • Site considerations should always dictate plant selection.

For more information, please visit Dr. Chalker-Scott’s web page at ​The Informed Gardener.

Dr. Linda Chalker-Scott Phd

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA Certified Arborist. She is Washington State University’s Extension Urban Horticulturist and an Associate Professor in the Department of Horticulture, and holds two affiliate Associate Professor positions at University of Washington.

She is the author of three books: the award-winning, horticultural myth-busting The Informed Gardener and The Informed Gardener Blooms Again, and Sustainable Landscapes and Gardens: Good Science – Practical Application, a comprehensive approach to the science behind urban horticulture and arboriculture.

Two other books are in progress: How Plants Work – A Gardener’s Guide to Plant Physiology (Timber Press) and an update of Art Kruckeberg’s seminal work Gardening with Native Plants (University of Washington Press). She has published extensively in the scientific literature magazines as well as in popular magazines such as American NurserymanOrganic Gardening, and Fine Gardening. She and three other academic colleagues host “The Garden Professors” blog and Facebook page, through which they educate and entertain an international audience.

This article was reprinted in The Michigan Landscape magazine, a publication of the Michigan Nursery & Landscape Association (MNLA.org).

Reprinted by permission to Sticks & Stones, June 2018

Eric Joy

Limited time – free local delivery

our Moffett

Take advantage of our industry-leading delivery service! We can deliver your plants, brick, or bulk items right to your jobsite - no need to rent a specialized vehicle - just let us handle it.

For two weeks this July we are offering FREE local delivery. From July 23rd to August 3rd, we will deduct up to $210 from your delivery charge. Our local area is highlighted in yellow on this map, but please check with your salesperson for details. (Click to zoom view)

Local delivery area

We have full-size semis and a smaller dump truck and each has easy-to-reach minimums to qualify for a delivery. There may be site access restrictions as well, so plan on discussing your needs with your salesperson so we can service you appropriately.

Semi Truck

Dump Truck

Plants

Pavers

$2000 minimum order

3 bundle
mix / match
 minimum


$35 Moffett fee if the tires touch the ground

$210 minimum;
$70 / hour

$140 minimum;
$70 / hour

Plants

Bulk

$1000 min to
 $2000 max order

Heavy stuff;
5 cu yd min to
10 cu yd max


Light stuff;
10 cu yd min to
20 cu yd max

$140 minimum;
$70 / hour

$35 flat charge inside the box

Present this coupon to receive your discount - delivery slots are limited, so book now! Your order must deliver between 7/23 and 8/3, 2018.

COUPON • FREE DELIVERY • JULY 2018

  • Up to $210 off your delivery charge
  • Order must deliver between 7/23 & 8/3
  • You must present this coupon
  • check
    This coupon has no cash value
  • check
    Limit one per company

Here’s the fine print: You, the contractor, are responsible for unloading the truck or trailer. Our driver is there to help, but you must have people and the proper equipment on site to unload the material.

Spotlight on ornamental conifers

obtusa aurea

Coniferous evergreen shrubs can be used for foundation plantings, hedges, screening, topiary or a stand-alone focal point, and if planted in the right location, they never disappoint. Narrow, wide, tall, or short and in shades of silvery blue to green to yellow, evergreen shrubs bring four-season appeal and must be included in any quality landscape design. 

Chamaecyparis brings many questions each year, and I’ll highlight some of our favorites.

Chamaecyperis obtusa - Hinoki Falsecypress: The obtusas have flattened sprays of arborvitae-like foliage. There are dozens of varieties available to the trade. These are the ones we try to carry every season.

C. obtusa ‘Aurea’: Full-size golden variety with spreading, graceful branches. The outer foliage is golden with a green interior. Can grow up to 12" per year. Use as a specimen or in a group as a focal point.

obtusa aurea

Chamaecyparis obtusa 'Aurea'

C. obtusa ‘Nana Aurea': Dwarf version of 'Aurea'. Slow growth rate of 1-6" per year. Maintains golden color all year long. High impact in a small package!

obtusa nana area

Chamaecyparis obtusa 'Nana Aurea'

C. obtusa ‘Crippsii’: Broadly conical with spreading branches and pendant sprays of bright, yellow foliage. Best in sunny or partially sunny areas. Good winter color. Excellent specimen. Growth rate up to 12" per year.

obtusa crippsii

Chamaecyparis obtusa 'Crippsii'

C. obtusa ‘Gracilis’: Broadly pyramidal and compact, the dark green lacy foliage is elegantly swirled. The rate is moderate, averaging 6-12" per year. It can reach 5-10' in ten years. Stunning specimen plant.

obtusa gracilis

Chamaecyparis obtusa 'Gracilis'

C. obtusa ‘Nana Gracilis’: Dwarf version of 'Gracilis', growing 1-6" per year. The rich green color makes it a focal point in any landscape design. An irregularly globose form that is beautiful pruned or natural. A favorite of bonsai artists.

obtusa nana gracilis

Chamacyparis obtusa 'Nana Gracilis'

Chamaecyparis pisifera - Threadleaf Falsecypress

C. pisifera ‘Filifera Aurea Nana’: This beauty is not a genuine dwarf, but a slow growing cultivar that can reach a height of six feet, though that is not common here in Michigan. Bright greenish-yellow to golden whip-like leaves and branches that grown into a haystack mound, this popular plant is hard to keep in stock!  ‘Golden Mop’ is a mutation of ‘Aurea Nana’ and a true dwarf. Other cultivars we carry are ‘Golden Charm’, ‘Golden Mop’, ‘King’s Gold’,  and ‘Lemon Thread’. We stock them all, but not all the time.

filifera aurea nana

Chamaecyparis pisifera 'Filifera Aurea Nana'

We are always looking for plants that will make your design stand out and these varieties deserve your attention:

Juniper chinensis ‘Daubs Frosted’: Light golden-yellow new growth matures to soft feathery bluish-green. We will have some this year on standard.

juniper daubs frosted

Juniperus chinensis 'Daub's Frosted'

Thuja plicata 'Whipcord': Hard to believe that this is an Arborvitae! 'Whipcord' is a dwarf selection of Western Red Cedar. It's a slow grower, getting only about 3' wide in ten years. The unsual whip-like branchlets give it a soft, mop-like appearance, making this a fun accent plant in the landscape.

thuja plicata whipcord

Thuja plicata 'Whipcord'

In closing, evergreen shrubs are an important element in any good landscape design. Next time you’re in the Plant Center have a look at the new varieties, and the great selection of ornamental conifers we carry. We are always looking for plants that will make your design stand out.

Clint Rasch

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