Archive for the ‘Air knife’ Category

At New England Grows, I met Jim Doyle, one of Wellesley College‘s team of arborists. He told me about an air-tool transplant that he and a colleague performed last November at the College.  He was kind enough to send photos, and with them included this text, which I have edited only slightly:

“My colleague Don Garrick and I performed the transplant on Nov. 3rd 2009.  The reason for the transplant was that the tree, a Picea glauca ‘Conica’ (Dwarf Alberta Spruce), had outgrown its current location and was providing too much shade to the greenhouse.  An old accession tag we found told us that the tree had been planted in 1956.

The tree in its original location, quite close to the greenhouse.

Jim using the airspade to locate the root zone's outer limits.

Don digging a trench outside of the root zone.

In this and in the next two pictures, Jim removes soil from the Picea's roots.


Working in from the perimeter toward the trunk.

Don lifts the tree out of the hole.

Transporting the tree to its new home across campus. The tree has been laid down for stability.

The tree in its new location, with plenty of room for continued growth up and out.

During the whole process we watered the roots every 5 to 10 min.  We wrapped the roots in wet burlap for the transport.  Once we had placed it in its new home, I sprayed the tree with with anti-transpirant and we then staked it, as its new home was a very windy location on the lake.  The stakes and guys will probably be removed this summer once we can confirm that the tree has settled well enough in its new hole.”

Here’s an example of the thoughtful management of plants on a property.  This Dwarf Alberta Spruce was in good shape, but had grown out of its original location, tucked behind the greenhouse.  Moving it was a fine way to save the tree, preserve the antique greenhouse glass adjacent to it, eliminate the greenhouse interior shading problem, and revamp the area — and now the tree, in its new spot, has room to grow and is visible to the Wellesley College community.

Project site:  Wellesley College campus, Wellesley, MA

Project arborists:  Jim Doyle, ISA-Certified Arborist; Don Garrick, MA-Certified Arborist

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Another question asked at last week’s New England Grows about bare-root transplanting was “How do you make sure the roots don’t dry out?” The answer, of course, is that you water the tree you’re moving.  You water it thoroughly a couple of days before the transplant, to insure that the tree’s tissues have good turgor pressure and moisture reserves for the bare-rooting.  You take a break every now and again during the blow-out (if you’re using compressed air) and spray down the exposed roots with water.  You may spray more water on the roots — the top, bottom, and inside of the root mass — when you pick the tree up on forks to deliver it to its new home.  You ‘mud in’ the tree as you backfill, saturating the backfill soil with water to eliminate any air pockets and again, to combat root dessication.   And once you have mulched the tree well, you water still more.

Water in all phases of the operation is key to tree transplanting.

Cornell’s Urban Horticulture Institute advocates using a hydrogel slurry to hold water on the bare roots during planting.  Their excellent Creating the Urban Forest:  The Bare-Root Method describes the process of planting young trees bare-root, and is well worth reading.  The challenge of using a slurry for large-tree transplanting would be in getting a consistent coating of hydrogel on the roots (you can’t dip the root plate in a tub, the way you can with a sapling root mass) — but there must be a solution (so to speak) to that problem. And finally, aftercare is critical.  Moving a large specimen tree bare-root takes time and effort, and it would be folly to follow all the steps, get the tree in the ground, and then leave its re-establishment and survival up to chance.  Some arborists add fertilizer and bio-stimulants to the backfill, some don’t.  What is essential, again, is water.  Consistent and adequate water for the first growing season is the best way to make sure that a transplanted tree makes the transition to its new home, survives, and thrives.

Watering in a root-washed pin oak at Cavicchio's Nursery. Photo courtesy of Carl Cathcart.

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Thousands of people showed up at New England Grows this past week.  One of the conference’s principal speakers, Bonnie Lee Appleton, unfortunately fell ill and had to cancel her Wednesday talk; for a while the day before the conference it looked as if one of the two convention center ballrooms would be empty for a couple of hours.  At the last minute, NE Grows asked Matt Foti to take Ms. Appleton’s place with a talk on bare-root planting.

The talk was great — packed with information — and sent a steady stream of people to the Foti Tree and Landscaping booth to learn more about bare-root transplanting.  Matt teamed with Teddy and Mike, two of his arborists, to field questions at the booth, which had a good set of air-tool transplant photos, a continually running rough cut of my London Plane video, and two 3-inch caliper Zelkovas from Matt’s nursery. One of the Zelkovas had been dug, balled, and burlapped; the other sat with its bare roots splayed on a sheet of plastic, showing off their extension (they extended about 3-4′ on all sides from the tree trunk), uncut tapers, and web of water-collecting and nutrient-storing capacity.  Every now and again one of the arborists would spray the roots with water.

It was cool to watch visitors to the booth stop and take in what they were seeing.  Some of them shook their heads and moved on; most, though, would watch the video for a few moments, or peer at the photos and the trees and start asking questions.  Matt and Timmy and Mike rarely had a moment in the three days when they weren’t answering questions.

A couple of questions popped up over and over.   Arborists, landscape architects, designers, and contractors all wanted to know how much air-tool transplantation costs.  The answer, based on labor requirements, species, condition, and size of tree, as well as on site conditions, was that bare-rooting a tree for transplant may cost more than digging it with a tree spade, but less than digging it with the more traditional drumlaced B&B method.  Bare-rooting a tree for transplant typically preserves at least 90% of the tree’s roots, though, a claim that cannot be made for the other methods.  The more roots you save, the less transplant stress and the shorter the tree’s reestablishment period — and all other factors being equal, the healthier the tree tends to be after transplant.

The other question, also coming from arborists, landscape architects, designers, and contractors, was about taproots.  How did bare-root transplant affect a taprooted tree?  The answer is that taproots are rarely an issue, at least in this part of the world.  In New England, soils tend to be shallow.  As we know, trees tend to develop their roots in the top 18″ of soil; the larger the tree, the deeper that zone may go, but typically it extends no more than 3 or 4 feet below grade.  Some thick roots do extend vertically down in this zone, but many more run horizontally away from the tree’s trunk.

It’s helpful to keep in mind another factor when thinking about taproots and transplanting trees.  More often than not, a large tree being transplanted was planted out years earlier as a B&B plant, or possibly moved into place with a tree spade.  Both methods would have cut any taproot in the initial planting.  When the end of a root is cut, the tree tends to send shoots out from just above the cut end.  In a vertically oriented root, the new shoots are apt to extend horizontally from the cut end, and feeder roots would similarly extend out horizontally.  The situation may well be different for a tree that has grown from seed in one place, that someone now wants to transplant bare root, but for most landscape trees the taproot issue is moot — whatever taproot may have existed when the tree seed germinated has already been cut, and the tree has adjusted for its loss.

A carrot grows downward, with rootlets out to the side and foliage above ground. A tree is not a carrot. Photo by obenson in Flickr.

This beech tree was moved last fall, having been transplanted once about 20 years ago. See how the root mass extends far out horizontally, with a relatively shallow depth.

This is one of the thickest roots extending vertically from the beech's trunk. This root was cut in the earlier (20 years previous) transplant; note the resultant root growth just above the cut.

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I just got a rough cut today of the video, shot last summer, of the moving of a very large (about 14″ caliper, 30′ height) London Plane Tree.  It’s taken a while to edit several hours of footage down to a half an hour, but it’s about done, and in the next few weeks I hope to have added commentary.  This video is from the project run by Matt Foti’s crew, aided by Mike Furgal, and it showcases the techniques used in air-tool transplanting.  I hope to be able to preview the rough cut at New England Grows, and have the final version completed by the end of February; if there’s enough interest in the arborist community I’ll sell copies.  Stay tuned.

The first of five 12-14' caliper London Plane trees being excavated with air tools and transplanted bare root in August 2009.

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To continue yesterday’s post on the bare-root transplanting of a Norway spruce at the Perkins School for the Blind in Watertown, MA:

The crew uses a heavy canvas strap wrapped securely (more than once) around the trunk, and pads the Bobcat fork bracket. This tree's flat back meant it could be pulled securely up onto the forks without tying up branches; other trees would need to be tied up for easier spading and transport. Here, the forks are poised to push under the root ball, just below the wire basket.

Rolando prunes thin fibrous roots from under the basket, to release the root ball from the ground. Most of the root mass has already been blown out.

Spruce on the move. With almost all the soil blown off the root mass, it is light enough for the Bobcat to carry the tree easily across campus. Canvas straps secure the tree to the Bobcat; Rolando rides along just in case.

Closeup of the root mass. Virtually all of the roots on this tree were quite thin, and they made a dense mat that extended about nine feet out from the tree's trunk on several sides.

Mynor had dug out the hole with the Bobcat while Sonia and Rolando blew out the soil from around the tree. This site, next to a busy campus parking lot, challenged the crew to place the tree carefully. Cars were parked just to the right of the orange barrier in this photo, and other relocated trees ringed the dish on two other sides, so maneuvering to get the tree in place was a bit tricky. It's relatively easy to spin at least a small B&B tree to the right orientation; turning an air-spaded tree requires a bit more forethought. In this situation, a bit of three-dimensional visualization was necessary to be sure that the flat side faced away from the parking lot.

Sonia and Rolando used a rake handle and tape measure to determine the root mass's depth before adjusting soil depth in the new hole.

Additional native soil is added and compacted to make a pad under the trunk. When in doubt, it's better to place the tree slightly higher in its new location than to risk it settling deeper once it has been backfilled and watered in; tamping the soil firmly under and around the roots right at the tree's base helps insure both that the soil won't subside and that air pockets are eliminated.

Rolando guides Mynor in setting the tree in the right spot. Good communication is key through this entire project, and these guys were excellent in coordinating their work with each other.

Rolando and Santo shovel native soil under the rolled-up root mat, to secure and level the tree before its roots get spread out.

Sonia and Rolando spread soil under and over the roots as they unroll them from the bundle. Note that they are using soil excavated from the site, with no amendments. Bare-root transplanting eliminates the difficulties associated with moisture transfer between two types of soil (root ball soil and soil outside the root ball), which makes establishment in its new site less stressful for the tree.

With backfilling complete, the crew builds a berm.

With the berm in place, Sonia waters the backfill thoroughly. Some crews shovel in the backfill and water simultaneously, "mudding in" the tree for extra stability and the complete elimination of air pockets. Mulch will go on this new planting next, and then more water. Note that you can see the root flare, now that the tree has been excavated from its original root ball and planted at the proper depth.

Project site:  The Perkins School for the Blind, Watertown, MA

Project manager:  Sonia Baerhuk

Project crew:  Rolando Ortega, Mynor Tobar, Santo Masciari

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The Massachusetts Arborists Assocation bare-root workshops — one in August 2008, and one in August 2009 — have been spreading word through the Commonwealth about the benefits of air-tool tree transplanting, and word is travelling throughout Massachusetts horticulture circles now.

A couple of weeks ago I was chatting with Kristen DeSouza, one of the horticulturists at the New England Wild Flower Society‘s Garden In The Woods, and she mentioned that she had passed my name along to Sonia Baerhuk, who tends the grounds at Watertown’s Perkins School for the Blind.  Kristen told me that Sonia and her crew have been using air tools to  transplant trees on the school’s grounds for the last several months, and suggested that I get in touch with her.

And so last Thursday, a couple of emails and a phone call later, I pulled in to the visitor’s parking area at the Perkins School.  Sonia soon arrived in one of the grounds department’s Gators.  She very kindly showed me around the campus, explaining that a new and large building project had required the removal of dozens of large trees.

It’s a scenario typical of many institutional sites:  a program outgrows its home, the phasing of a master plan leads to a shifting of facilities or the construction of a new building, and the vegetation on site must either be removed or relocated.  Having worked at Perkins for several years, Sonia was no stranger to this course, of events, but still, she had been dismayed to see so many large specimen trees being cut and fed into the chipper.

Though the grounds crew does most of its own tree work, over the years they have called in arborists for their expertise, and Sonia knew and trusted Matt Foti’s expertise.  Matt had told her about the air-tool method, and on the strength of his recommendation, she signed up for the MAA’s Elm Bank bare-root workshop this past August.  At it, she absorbed as much information as possible.  She came away from the day’s event convinced that air-tool excavation and transplant was the best way for her crew to relocate any salvageable campus trees.

So Sonia and her boss Rich Falzone equipped the crew with an Air Spade and an Air Knife, coveralls, eye protection, ear protection, and respirators, and began to direct the relocation of trees.

To date, the Perkins crew — Sonia Baerhuk, Rolando Ortega, Mynor Tobar, and Santo Masciari — has moved several 15-20′ Norway spruce, a fastigiate white pine, a Forest Pansy redbud, several apples, and a beautifully structured 25-30′ tall Halesia.

On the day I visited, they were ready to move another Norway spruce from a location that is slated to become a pondside patio.  Its new home would be a lawn next to a parking lot to which they had already moved a number of evergreens.  The new planting is beginning to screen the lot from adjacent buildings; over time, this grove will shade the parking lot and the walkway near it.

Sonia Baerhuk marking the new home of a 15' Norway spruce to be relocated.

Fifteen-foot Norway spruce in its original location next to the campus pond. The crew discovered that the Norway's roots were interwoven with roots from other nearby trees. This tree was flat on the side facing the fence.

Currently, the grounds crew rents compressors. These two generated air for an Air Knife and an Air Spade. Note the plywood barriers set up to prevent soil overspray onto the lawn. In this project, the crew did not dig a trench to hold blown-out soil; they simply started blowing soil out from the trunk and followed the roots out to and beyond the dripline.

Sonia and Rolando, kitted out in their PSE: coveralls, gloves, hats and hoods, ear protection, eye protection, and respirators.

Blowing soil off the roots took about three hours. Sonia likes to divide the root mass diameter into quadrants and work systematically, while Rolando prefers to work all around the tree; when they work in tandem they use whichever method fits the site conditions best.

Edges of the original B&B root ball are barely visible here; it was roughly 24-30" across. Rolando and Sonia discovered the wire basket still around it. They also discovered that the root flare sat several inches down in the original root ball.

The spruce was anchored with a thick mat of fibrous roots; the crew found virtually no roots larger than 1/2" in diameter. Here, they are pruning root ends under the eighteen-inch deep mat.

Still pruning the mat, and rolling it up toward the trunk to blow soil out from under the tree.

The root mat rolled up and bound in burlap for further blowing-out and moving.

Project site:  The Perkins School for the Blind, Watertown, MA

Project manager:  Sonia Baerhuk

Project crew:  Rolando Ortega, Mynor Tobar, Santo Masciari

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Mike Furgal sent me photos of an 8″ caliper Weeping White Pine  that he moved a couple of weeks ago, remarking that this tree, though relatively small, was the most challenging tree he’s moved bare-root.

The tree was situated in a small berm next to a house and a driveway, and shared the bed with a 7′ Hinoki Cypress and an 8′ Blue Holly.  Mike blew soil out of the entire bed to move all three plants, whose roots were interwoven.

Pine roots running toward the house and drive extended no more than three feet. Roots running under the lawn told a different story; the two main roots that Mike found were 16-18 feet in length; they had plenty of moisture available and plenty of rooting room to grow.

Mike began work on the bed by blowing soil at the tree’s dripline and at its root collar, to assess where the roots were.  He found that they ran along the edge of the bed until they hit the house; from that point they grew out into the lawn.

Here are his photos:

beginning location 2

Rooting space is constrained by the berm's proximity to the house and the driveway.

begining location 3

Ample lawn space gives plenty of rooting opportunity in other directions.

beginning location 1

Lots of roots here -- note how they run along what had been the bed edge, and extend back toward the house. Once they hit the house, they then ran out into the lawn.


Here's what the excavated bed looked like, with Hinoki Cypress, Blue Holly, and Weeping White Pine roots woven together.

veron pine diggiing

Tremendous root extension can be kept with air-tool excavating, and while not all fine roots remain, a significant number of them do.

veron white pine digging 2

The Pine ready for its move. These lawn-side roots are sixteen to eighteen feet long. Compare that root length to the accepted standard size of a B&B root ball, which allows ten inches of root-mass diameter for one inch of trunk caliper. For an apples to apples comparison, if we include the three feet of root on the tree's other side, this tree has 19 to 21 feet of root extension, as opposed to the 6-foot, 8-inch root mass diameter you would see on a B&B specimen.

veron white pine digging 3

Moving the excavated pine was the trickiest part. Mike and his helper used a Bobcat and a Dingo -- tricky to coordinate both machines at once.

veron moving 3

Closeup of the two monster roots extending away from the house and drive.

veron moving 1

Anyone else reminded of a bride with a really long train? One major difference: a bride doesn't require this kind of machinery to move around.

veron moving 2

The pine moving to its new home on the other side of the house.

I’ll post photos of the tree in its new location shortly.

Arborist:  Mike Furgal, Furgal Tree and Landscape, Northborough, MA

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Posted on Taking Place on July 1, 2009:

A few posts back I mentioned my February 2009 article in Lawn and Landscape Magazine on bare-root tree transplanting using an air spade. That article was preceded by my December 1, 2008 article in American Nurseryman, in which news of the technique debuted. Both articles describe the workshop at which several trees — a Juniperus virginiana, a couple of Acer palmatum, a couple of Betula pendula ‘Gracilis’, among others — were spaded and moved. Both articles outline how to carry out the process, though the Lawn and Landscape article is a bit more explicit. And they compare the merits of different methods of transplanting (tree spaded, ball & burlap, and air spade), including how cost, speed of operation, and effect on tree health may vary.

The beauty of using an air spade to transplant specimen trees is that so much root mass can be preserved and moved with the tree. The following photos of a dwarf Japanese maple (Acer palmatum dissectum), lent by Matt Foti, illustrate just how effective at saving roots this technique is.

Matt and his crews are using an air spade routinely now in transplanting work, because it preserves the tree’s resources so well, minimizing transplant shock and easing re-establishment. They moved this tree in early September of 2008. Take a look:

Acer palmatum dissectum awaiting its move.  Soil under the tree has been lightly spaded to check surface roots.

Acer palmatum dissectum awaiting its move. Soil under the tree has been lightly spaded to check surface roots.

Same tree, roots now exposed by the air spade.  Note how far beyond the tree's dripline these roots extend.

Same tree, roots now exposed by the air spade. Note how far beyond the tree's dripline these roots extend.

Tree being lifted up for the move.  The crew has wrapped its trunk and main limbs, to avoid injury; guy lines insure that it won't tip in transit.

Tree being lifted up for the move. The crew has wrapped its trunk and main limbs, to avoid injury; guy lines insure that it won't tip in transit.

Wrapping thoroughly during this kind of move lessens the chance of bark injury.

Wrapping thoroughly during this kind of move lessens the chance of bark injury.

Tree in its new location, backfilled and awaiting thorough watering.  No staking is necessary, as most of the root plate has been preserved and will continue to support the tree in its new home.

Tree in its new location, backfilled and awaiting thorough watering. No staking is necessary, as most of the root plate has been preserved and will continue to support the tree in its new home.

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No, that’s not a shot of a revolutionary way of planting in pavement — that’s a photo of one of the enormous China Girl hollies being taken to its new home at the property belonging to L. and A., my longtime clients. This holly is a mature plant; in my Air Spade In Action post (May 16), you can see it set on the ground, opened to its full, voluptuous 9′ width.

You’ll also notice that shrubs flanking the steps and walk here are mostly mature plants. L. and A. have spent years developing their landscape, and it has the flavor of a place owned by art appreciators. The plants have been tended with care, diligence, and skill, and their character reinforces the design intentions evident throughout the gardens.

Landscape architects often heed Frederick Law Olmsted’s dictum, “Plant thick, thin quick” (a motto we learned in Lenny Mirin’s Landscape History class at Cornell — Lenny?), and plant shrubs more densely than the mature size of the plant might dictate. Clients often want to see immediately gratifying plantings, which means a minimal view of the mulch and a maximal view of plants.

Which is fine — as long as someone goes back in a few years later and actually does the thinning. The making of a landscape is not a one-off deal.

At the North Shore garden this past week, as we were in the midst of reworking two areas on the property, I had a revelation. My clients have been devoted to their gardens for years, and they enjoy and promote the evolution of their place. Their enthusiasm for their landscape has allowed me to make the refinements that continue to animate it.

Thinning out the plantings is one aspect of this work: dismantling the holly hedge gave us ten wonderful plants to use around the property, while allowing us to develop a planting in place of the hedge that uses a combination of new, younger plants and older transplants that have grown into their habits. Toby and I have discussed in earlier posts the idea of planting densely and allowing the plants themselves to elbow each other both into a coherent ensemble and into a set of individual character actors.

This week, I was able to take mature, idiosyncratic plants — in this case, rhododendrons, azaleas, and mountain laurel — and transplant them in an area where each plant’s form would be visible. This sort of refinement is possible when a landscape has been designed, planted, and growing for years; it is the stage at which the character of plants can truly be showcased.

Not every landscape reaches this stage, which requires something of the eye of an editor and a knowledge of horticulture in addition to the skills of a designer. A property may be sold, a client may find other priorities, or may simply feel overwhelmed by the “planted thick” place. Rather than thin it out or make new spaces in the landscape, that client or new owner may ask for an entirely new planting.

Refining a landscape by reimagining its plantings, though, and in some cases developing new spaces to fit a changed use of the property, can breathe new and vigorous life into a place. Mature plants, well-situated, give a well-structured place the look of inevitability that is difficult to achieve with the callow youth of new nursery-grown stock.

Some of my favorite work has involved shaping spaces with mature plants reused from the same site. I tend to see character in plants, and really like gussying them up to highlight that character. Putting together a collection of plants in this way is like developing the singing skills of a choir; individually, each singer’s voice is distinctive, and together, all the voices blend to create shifting and satisfying harmonies.

This kind of design starts with a plan, but requires an agile mind onsite, as the plants move from one situation to another, and relationships among their forms change. It’s challenging to see a plant from all sides, envision how it will work in harmony with the others to join it, be sure it works horticulturally, and assemble the collection to best effect.

There is no way to plan precisely that kind of work in advance; the joy of it comes when shifts, tweaks, and adjustments bring about a result that fits just right, and that pleases. This week, I got to spend three days of orchestrating this kind of work, and every minute was a pleasure. Here are before and after photos of one planting area we changed:

p1010537Same area, newly revised. The existing trees remain, and we’ve added another little Bloodgood. The great wall of China Girls is gone, we moved two of them back in front of the Norway maple to grow more loosely together as a backdrop to two mature azaleas. Older rhododendrons and mountain laurel show their forms to the left of the new Bloodgood. New Green Wave yews will grow together and in a few years will make a continuous loose line with the existing Green Waves.

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This past winter I developed plans for a couple of areas on the property belonging to my longest-standing and wonderfully enthusiastic clients, L. and A. on the North Shore. They have a lovely place on a rocky cliff overlooking Nahant Bay, and they enjoy making it even more beautiful and comfortable each year. They are both artists, and both appreciate art in two and three dimensions: L. gardens and sculpts; A. is a talented photographer.

L. and A. had asked me to figure out how to screen out views of two neighbors from their house, and to develop plans in the two areas that would work with the extensive mature plantings already in place. I drew up plans that would bring a few new plants in, as well as reuse a number of plants already onsite. L. and A. liked the ideas, and we scheduled a date to move ahead.

Leahy Landscaping of Lynn carried out the work of digging and moving the plants; the crew, led by Anibal Marita, was excellent. At my request, and under the supervision of Mark Bolcome, Leahy’s arborist, they used an air spade on the project; we were working in a heavily planted area and I wanted to disturb or lose as few roots as possible.

The plan:  Remove a 32′ long, 7′ high holly (<em>Ilex ‘China Girl'</em>) hedge from the edge of a residential drive court, reusing some of the plants for screening at the front property line, and install a collection of transplanted shrubs, a new Japanese maple, and some low Green Wave yews where the holly had been. Transplant most of the hollies to provide a 22’ long screen at the front property line, and use the rest at another location onsite.

Proposed methods:  Hand-dig the holly. To avoid further stressing the three aging red pines under which some of the hollies were to be transplanted, excavate the transplant site with an air spade. Hand-dig the rest of the plants.

Actual methods:  Hand-dug the holly, then air spaded the root balls to loosen the nursery soil at their cores. Discovered that the wire baskets had not been removed at the original planting, removed those, and loosened the remaining soil, leaving roots intact. Removing the soil allowed the plants to fit in shallower-depth holes, which was helpful on a site with a lot of existing tree roots and drainage pipes. Removing the wire baskets will allow the hollies’ roots (and crowns) to grow unimpeded in their new locations. Excavated under the pines with the air spade, and removed existing shrubs there also with the air spade, leaving all roots, including masses of feeder roots, intact. Unwrapped the Japanese maple root ball, removed the wire basket and burlap, and removed/loosened the soil with the air spade.

Removing a girdling root from the Japanese maple.  Note the root-ball soil line, four inches up the tree's trunk from the base of the trunk flare.

Removing a girdling root from the Japanese maple. Note the root-ball soil line, four inches up the tree's trunk from the base of the trunk flare.

With a mini-claw mattock, pulled soil away from the trunk flare; soil had been piled 4″ up the trunk, concealing a girdling root and the flare itself. Mark Bolcome chiseled away the girdling root and made sure the flare was correctly exposed before laborers backfilled and watered in the root ball.

Removed the red clay soil encasing the nursery root ball of a rhododendron that had been planted onsite several years ago, but that had struggled for those years.

Breaking up the clay soil in the root ball of a 4' rhododendron.

Breaking up the clay soil in the root ball of a 4' rhododendron.

With the concrete-like soil mostly gone, the plant should finally have a chance to spend its energy growing, rather than trying to break through that clay cast.

Cleared ground cover by hand in front of a row of mature Taxus trees,

Holes for holly transplants were dug by air spade, to minimize disturbance to the roots of the treeform yew hedge behind the plywood.

Holes for holly transplants were dug by air spade, to minimize disturbance to the roots of the treeform yew hedge behind the plywood.

then excavated transplant holes with the air spade — again, to keep from disturbing roots of the existing yews — and transplanted more of the holly here.

The original plan, which also included the planting of six large clump bamboos and the moving of several broadleaf evergreen and herbaceous plant, was scheduled to take perhaps two days. The hollies changed everything, though. They were enormous: planted eight or nine years ago at 3′ on center, they opened out to seven to eight feet in width.

One holly, trussed for moving.  Ten of these plants had been placed on 3' centers to make a hedge; when freed from the hedge, each one opened out to cover at least seven feet in breadth.

One holly, trussed for moving. Ten of these plants had been placed on 3' centers to make a hedge; when freed from the hedge, each one opened out to cover at least seven feet in breadth.

There was no way we could fit them all where we had intended; they would have taken up more than seventy linear feet if we had placed them side by side!

Hand-dug holly that has been bare-rooted being prepared for transplant. Notice the clumps of hard, heavy soil from its original root ball lying around it; the wire basket is lying off to the left.

Hand-dug holly that has been bare-rooted being prepared for transplant. Notice the clumps of hard, heavy soil from its original root ball lying around it; the wire basket is lying off to the left.

The trussed holly, now untied and moved to the planting bed, is at the back right of the photo. Liberated from the crush of a too-tight hedge planting, it has opened out to cover almost nine feet of fence.

The trussed holly, now untied and moved to the planting bed, is at the back right of the photo. Liberated from the crush of a too-tight hedge planting, it has opened out to cover almost nine feet of fence.

So it took a while to figure out where to put them, and then more time preparing those new locations to receive them. We ended up placing them — ten from the hedge, plus a shorter male plant — at various points around the property’s edge, where they do a magnificent job of screening out the neighbors.

Accomplishing the work took a full three days. Lessons learned:

1. An air spade is a great tool for any kind of planting work. We tested its capabilities, and found it invaluable for working under trees, for bare-rooting new plants, for excavating existing shrubs, and for removing that dreadful red clay soil from the 4′ rhododendron. We used it to investigate suspicious root issues — that concrete-like slug encasing the rhody’s root mass, the hollies’ wire baskets, the Japanese maple’s buried root flare and girdling root — and when it wasn’t being used on the transplanting operation, we used it to give a little breathing room to the root flare of a river birch planted on site a few years ago.

On this particular site, which has been intensively gardened for decades, the soil is beautifully dark and rock-free. The air spade had no difficulty blowing it out of planting holes. Even with a rockier soil, an air spade has enough pressure (90 psig) that bare-rooting shrubs takes a relatively short time. A laborer team can generally dig a 4-5′ broadleaf evergreen shrub in minutes. An air spade can do it as quickly or in a few more minutes, depending on soil type — but the amount of root mass saved makes the air spade by far the preferred method, horticulturally.

2. Plywood screens work beautifully to confine the overspray of soil from the spading site. For bare-rooting the already-dug hollies, the landscapers figured out that they could lift each plant into the back of their high-sided truck and spade off the root soil there, which kept the soil contained and the site clean.

3. At a minimum, workers using the air spade or helping with the bare-rooting should wear goggles and a face mask; very fine particles of soil spray everywhere at high pressure, and eyes and lungs should be protected. In rocky or sandy soil, the hazard is greater, and long sleeves and protective visored helmets are a good idea.

4. Never plant China Girl hollies that close together. They have a lush and luxuriant round form, and are determined to grow to that form (shrubs will push to grow into their particular habits — with some, you can push back by hedging them, but it makes sense to pick a variety whose natural habit lends itself to hedge form). Ten hollies had been planted at 3\’ o.c. to make a hedge; when removed from hedge configuration, the plants spread to between seven and nine feet in breadth. These plants now make a contribution to the landscape that they couldn’t in hedge form.

L. couldn’t remember if the original plan, done by another LA, had called for China Girls or for some other holly, and wondered if the contractor might have substituted China Girls for something else. We’ll never know — but we’ll know what to avoid in future.

Conclusion: The planting techniques were first-rate, the plants looked happy, the place looked great. L. and A. are delighted with the results (I know I’ve succeeded when I’ve pleased their artists’ eyes), and Leahy is moving on to do other air spade projects, knowing how well the technique works in a number of different situations. Now we’ll all be watching to see how everything grows; I’m betting they will all thrive.

Company:  Leahy Landscaping of Lynn, MA

Leahy Project Manager: Aisha Lord

Leahy Arborist: Mark Bolcome, MCA

Leahy Foreman: Anibal Marita

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