Plant care – Page 5 – Sticks & Stones

Are native plants always better?

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.

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.

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 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 Nurseryman, Organic 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

Don’t be “that” guy!

On my commute to work I pass a recently landscaped site that has a lot of plants still sporting their plastic tags.

I say "recent" but I really mean SEVERAL MONTHS. Seeing those tags flapping in the wind really detracted from a very nice landscape job!

Nursery growers and re-wholesalers put tags on plants for identification, not for decoration. I can see leaving the tag on for a few days on a residential job so the homeowner knows what was planted. But you probably gave them a landscape plan with everything identified on it, making those bright plastic tags unnecessary. On some commercial jobs I’ve seen tags left on for years, until they weathered off. It's not a good look.

Not only does the tag look bad, it is unhealthy for the plant. Plastic tags can girdle branches on trees, and large portions of smaller shrubs. I have personally removed tags that have become embedded in the bark as the plant grew. It does take a few extra minutes, but having your crew take those tags off will make your install look as professional as it should. Have them do this as the parting site-cleanup as they remove scraps of burlap, lengths of tagging ribbon, and snarls of tying twine. You want your client - and all his friends and neighbors - to admire your work without distraction.

Bad Karma

It has always seemed that many things were just meant to be. Peanut butter and jelly, perhaps the greatest love affair of all time. Romeo and Juliet, Desdemona and Othello, Mr. Darcy and Elizabeth, Ozzie and Harriet, Mork and Mindy, Gertrude and Heathcliffe, Joe and Kirsten, Bonnie and Clyde – the list is endless! But humanity is cursed with its fatal flaws. Peanut butter and jelly – they don’t really mix and the jelly oozes out the side of the bread. Romeo and Juliet are tragic star-crossed lovers. Othello has a serious problem with jealousy. Mr. Darcy and Elizabeth get past their pride issues, but eventually the book has to end. Ozzie and Harriet, as well as Mork and Mindy, get cancelled. Joe and Kirsten’s Days of Wine and Roses turns to Brandy Alexanders – not a good finish. And, a life of crime does not pay off for Bonnie and Clyde.

Plants, or combinations of some plants, can have similar tragic results. Some planting designs look great but eventually nature unleashes it’s fatal flaw. The design of some landscapes brings out the worst in some plant varieties. A number of these ill-fated arborial marriages exist but the coexistence of pears and junipers requires our attention.

The ubiquitous Callery Pears, strong and adaptive growers, are increasingly being bothered with Pear or Trellis Rust. To blame are junipers. And vice versa. Together they create a perfect storm scenario for the fungus, Gymnosporiangium fuscum. This is a dark, bare capsule on junipers which explodes with orange, jelly-like fingers during cold, wet springs. These galls cause dieback in junipers and rust colored spots and scabs on the leaves of pears as well as lesions on their branches. Proximate use of these plants is a marriage gone bad; under certain conditions they bring out their worst attributes.

Removal of affected plant material is part of the solution. Putting appropriate distances between host and parasite plants is another. Callery Pears are great trees for parking lots and streets where drier conditions prevent these fungal outbreaks. Systemic fungicide treatments are available. However, both groups of plants are fairly durable and recuperative. No matter how well they might look together their combination is just bad karma.

Plantings of Pears and Junipers are like the tit for tat relationship of Gertrude and Heathcliffe (if you’re not over 50 - look it up!). There is no real fatal flaw, but a lot of bumps and bruises along the way.

Please check out the linked article for more details.

Trellis Rust Management Update by Dr. David Roberts, MSU

Oh deer!

Whitetail deer are beautiful animals. It's surprising to see how successful they are in urban and suburban areas.

You'd better drive with caution, too, especially around dusk and dawn. And where there is one, there are usually others, so watch for deer number two or three to dart across the road. Car crashes are never good for anyone involved.

As nice as it is to see them up close, they come for one thing, to eat our landscapes. We have no one to blame but ourselves for invading their space.

So what can we do to protect our investment? Start by putting the gun down, your neighbor might complain about the holes in their garage.

There is a list of plants that are deer resistant in our new mobile app, but if you already have everything planted or can’t find the same look you want and need to plant those edible deer plants, there are products on the market you can apply to keep the deer out or limit the damage.

Christensen’s carries a couple of products that have been tested over the past 10+ years and have produced good results.

Deer Scram by Epic is a fine granular that is applied as a perimeter defense. This all natural, organic product is easy to use and does not have an offensive odor. The product will last 3-5 weeks before you need to reapply and it works year round. It has the added benefit of being a mild fertilizer.

Liquid Fence Deer & Rabbit Repellent is applied directly on the plants. It has an odor and taste the animals detest. This product will last 2-4 weeks depending on weather. The rain will dilute it quickly and it must be reapplied often.

Sometimes a physical barrier is required, so we also carry Deer Fence. It comes in a 7’ x 100’ roll and can be used to protect a large area.

Planting in heavy soils

Heavy clay soils are one of the toughest environments to plant in, but there are no hard and fast rules to follow. Whether the planting site is irrigated or not, and how much irrigation it’s receiving is crucial information. Here is an example: Concolor Firs will often decline and die in a heavily irrigated clay soil. In a lightly irrigated setting they will do fine.

Many planting guides will tell you to excavate 2-3 times the root ball diameter and amend the soil with top soil and peat moss. This is a big mistake! When you do this in a heavy clay soil you create a large “bathtub”, which can fill up with water in a heavy rain and drown your trees and shrubs. Digging a hole just large enough to hold the root ball reduces the amount of water around the plant.

Planting a little or a lot high to grade, depending on how wet the soil is, can be a good defense strategy. Just use a well-draining topsoil to feather out from the top of the ball to the top of the surrounding soil.

This columnar oak was planted at a correct depth in a raised bed. See below for a closer view.

One of the biggest mistakes I see is planting trees above grade on the top of a berm. Trees subjected to this treatment will almost surely die! Any rain (other than an all-day soaker), runs right off the berm. In this case create a shallow basin and plant below grade to capture those quarter to half inch mini rains.

Water: too much – or too little?

WATER, WATER, EVERY WHERE
And all the boards did shrink;
Water, water, every where,
Nor any drop to drink.

Some may recognize these verses from Samuel Taylor Coleridge’s “The Rime of the Ancient Mariner.” Even if one does not, it is worth noting this work, now approaching 200 years since it was written, was one of the first works advocating a more responsible use of our natural resources. The mariner’s senseless killing of an albatross leads us to question how we use and treat the fauna of this planet. Much of what is written could be applied to the flora as well.

If we remember back to this spring, days of rain created saturated soils and standing water. This did not bode well for some plants. In Coleridge’s story the sailors had no fresh water to drink, but here our trees and evergreens had more than enough fresh water, yet still could not absorb that water. Why not?

Stranded in the equatorial waters of the Pacific all but the ancient mariner eventually die from heat and lack of water.

The overabundance of water and saturation of the soil interfered with a plant’s ability to respirate and to absorb nutrients and water through its roots. The cold, wet spring also encouraged the growth of fungi, like Phytophora, in the soils which can cause lesions on the roots, which, in turn, interferes with a plant’s ability to metabolize whatever it needs. This is called root scald. At first glance some trees looked like they were wilting, in some respect they were, their roots were unable to take in nutrient and moisture causing the plant to collapse. Usually if a plant is dry leaves will wilt, turn yellow from the inner and lower branches, and the plant will begin to drop foliage to compensate.

When a plant is too wet it will begin to wilt only to have the apical branches turn reddish -brown but not separate from the plant.

How can one prepare for weather extremes? First, there is more than one way to plant a tree. Common sense goes a long way! Planting depth, the type of planting media, and choosing plants that will tolerate different soils are basic questions any landscaper should be considering for every site. It isn’t rocket science, but there is a lot more to landscaping than digging a hole and throwing the plant in!

Does the site drain well? If not, should I elevate plants in beds that will cause excessive water to run off? Choosing plants with higher metabolisms, plants with dark, more fibrous roots that can handle periodic or ephemeral flooding and including beneficial mycorrhizae in the planting media to protect root nodes will lead to transplant successes. If your planting losses are over 10%, is it due to lack of planting experience and good practices, or is your company guilty of cutting corners and careless installations? Even if you are not warranting your work, poor workmanship will catch up with any company eventually.

If heavy plant losses are “an albatross around your neck,” be a “sadder and wiser man,” and question practices and losses. Remember “the best gardeners have killed just about everything!” Becoming a more responsible contractor and pursuing best planting practices Will reduce losses and increase the bottom line. It pays to care!

“...but this I tell to thee…
He prayeth well, who loveth well
Both man and bird and beast.

He prayeth best, who loveth best
All things both great and small;
For the dear God who loveth us,
He made and loveth all.”

Five steps to quality

What goes into Christensen’s Plant Center having the freshest, most viable stock?

It began years ago when Lee Christensen (and probably before him his dad Pete) sought out material from the finest growers in North America. When Lee passed on the company to Tim Joy and Frank Huber, that sourcing experience of finding nice material at a good value was part of the deal. Over the years Christensen’s has cultivated relationships with a number of top-notch vendors, and our current Investment team of me, Kim Roth and David Dermyer as well as Frank Roth at Rushton Farms are focused on nurturing and expanding those relationships.

Secondly, the material is shipped by trucking companies we broker ourselves, then unloaded by our highly trained (and sometimes overworked) receiving staff. They can unload 8-12 trucks in a day and 1000’s of boxwood and yews in a week. All plants are placed in our facility under irrigation, both in the yard or the field. Maintaining that irrigation system is a top priority for our yard manager Chris Nielson (assisted by Rigo).

Third, the material is evaluated and approved as it gets unloaded or shortly after. If we see anything wrong, it gets rejected. If I wouldn’t buy it for myself, why would I sell it to you? Sub-par material is often put right back on the truck.

We make sure that plants are viable, rooted, and healthy. Plants that don’t pass this evaluation are removed from inventory immediately. Rarely, we receive trees in the spring that are rejected for quality but are not able to be shipped back to the vendor. We put the best of them in our “2%” area, and offer them to you at shockingly low prices.

We do want to be fair to our vendors, so if material arrives early in the year, we give the plants till early June to come out of dormancy. It’s amazing how some will take that long (like trying to wake up a teenager on a Saturday morning).

Finally, the other main force for refreshing our stock is you, our customer. Quick stock turns are key. If you’re busy planting, our staff is busy doing what Lee, Tim and Frank have trained and asked us to do. We are experts at finding quality material and are ready to provide what you need for your installs.

We know your success is our success, and we are glad we can help.

Beware the late frost!

Barring tornadoes and earthquakes, few weather occurrences strike fear into the hearts of the avid gardener, landscaper, and nurseryman like a late frost. We have no control over Mother Nature, if she decides she wants to paint everything white on a chilly spring morning. But there are things we can do to protect our plants.

Frost occurs on clear still nights. In late spring a light frost (28-32 F) can harm tender plants, magnolia blooms, and can kill annuals. A hard frost (25-28 F) can kill root hardy perennials and harm new leaves on woody plants. Below 25 F can harm many plants in late spring, mainly due to desiccation. Since temperatures can vary a few feet off the ground, smaller plants can be affected by a frost even if your thermometer reads above freezing. Most weather stations and apps will report a frost advisory, so pay special attention if you have vulnerable plants. Making sure to select plants that are suitable to the Hardiness Zone where they are being planted will reduce the risk of damage, and reduce anxiety over frost.

Types of frost include Hoarfrost (feathery white frost crystals), Rime (fog or dew frozen into a glaze), and Black Frost which is when there is no actual frost formed but the low temperatures are still harmful to the plants.

When is it safe to stop worrying about frost in Michigan? That depends on where you live. According to the Climactic Data Center website, in Ypsilanti it’s May 5th, in Detroit and Ann Arbor it’s May 10th, in Flint and East Lansing it’s May 28^th, and if you live in Tahquamenon Falls it’s July 9^th. Unfortunately nature doesn’t consult the Climactic Data Center website and can easily send a harmful frost your way beyond these dates, so be vigilant in late spring.

Some trees that are susceptible are early budding evergreens such as Black Hills spruce and Concolor fir, and deciduous trees including Sycamore, Lilacs, and Honeylocust.

So what can you do to protect your plants during a late frost? If you haven’t planted them yet and you have the space, bring them indoors (a garage, shed, or enclosed porch will do). Smaller plants can be covered with overturned pots or buckets, and larger plants can be covered with fabric, old bed sheets, or burlap (be prepared and have these items on hand before you need them). Another good method is to use your irrigation system. Watering your plants before and during below freezing temperatures helps prevent desiccation, and the water has and insulating effect on the plants and soil.

What if your plants are damaged by frost? If they are annuals or garden vegetables, they are probably toast. The effects on most landscape plants is cosmetic and plant survivability is good. The healthier the plant is, the more reserves it has to push new growth, so it is important that the plant is in the right environment and is well fed and watered.

Hopefully we don’t have to fret much longer about frost as the warmer months head our way, but don’t let your guard down yet. The Late Frost will get you if you do.

How to properly mulch

While you can apply mulch any time, early spring clean-up is prime time to freshen up the beds with a new layer of mulch. Jermi is here with a some tips on best practices for mulching.

When should you use Holly-tone®?

Holly-tone ® is a fertilizer designed to feed plants that prefer to live in acidic soils. Some examples of acid-loving plants are: azalea, dogwood, rhododendron, ferns, hemlock, holly, hydrangea, juniper, arborvitae, magnolia, Japanese Andromeda (pieris), pachysandra, vinca and many other evergreens.

In new plantings, dig a hole twice as wide and about as deep as the root ball. Add some compost, humus, or sphagnum peat to the soil - not too much, current recommendations are to use mostly native soil when backfilling.

Add one cup Holly-tone ® and mix thoroughly. Holly-tone ® is an organic, slow-release fertilizer and is enhanced with Bio-tone ® microbes, so it is very safe to use.

Established acid-loving plants should be fed twice yearly, spring and late fall. Sprinkle Holly-tone ® around like adding salt and pepper to food. If the area to be fed is mulched it is preferable to remove the mulch, feed, and then restore the mulch on top of the application of plant food.

Shrubs such as hollies, azaleas, and rhododendron use 1 cupful of Holly-tone ® per foot of branch spread. Double the quantity if spread is 3 feet or larger. In the spring, trees such as hollies, hemlocks and juniper use 1 lb.* of Holly-tone ® per inch of trunk diameter. Triple the quantity for diameters 3 inches and over. In the fall plants should be given a light feeding in the late fall.Use half the quantities recommended for the spring.

*One pound of Holly-tone ® equals approx. 3 cupfuls

« Previous 1 … 3 4 5 6 Next »

Archive