Category

Trees

Sep 30
0

Why Persian ironwood rocks!

By | Arborist Insights, Species, Trees | No Comments

I discovered the Persian ironwood tree (Parrotia persica) in 2014 while working for municipal gardener Tracey Mallinson. We had many of these trees at the Poirier complex in Coquitlam, BC. But I didn’t expect this tree species to rock the Urban Foresters Symposium. It was mentioned in two lectures and for good reason. It also appeared in the plant ID contest as one of the 25 specimens.

 

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Bullet proof

 

In lecture one on urban street and landscape trees, the lecturer referred to Parrotia persica as bullet-proof. Then he introduced us to three new Parrotia persica cultivars (cv.).

Parrotia persica cv. ‘Ruby Vase’ has a more compact crown while P. persica ‘Vanessa’ has a narrow crown habit. The third cultivar is the most interesting. Called P. persica cv. ‘Persian spire’, it’s a slow-growing non-aggressive street tree or it can be used as a hedge plant. The leaves have an awesome purple boarder.

 

Lecture two

Lecture two covered moisture stress in the landscape. While the lecturer didn’t want to recommend specific species he did cover three tree species he liked. One of them was Parrotia persica, our new bullet-proof friend.

It can handle drier conditions because it comes from the high deserts of Iran. Thus the specific epithet “persica”. It has thick, somewhat hairy leaves. And it tolerates drought and alkaline soil conditions. It doesn’t suffer from any diseases and it has beautiful fall colours.

Cons

Parrotia persica is a slow grower; and the specimens I know from my landscapes tend to have irregular crowns because once in a while a branch pushes out of the crown. But again, it depends on who is looking. Personally, I have no trouble with some idiosyncrasies. Other people freak out when the crown isn’t perfectly round.

I don’t recall any problems with this tree species on any of our strata sites. So bullet-proof it is.

 

Perottia persica

 

Conclusion

If you’re considering what tree species to plant as our climate goes drier, the bullet-proof Parrotia persica is a great choice. You can try any of the three cultivars mentioned above; and you should expect decent fall colour.

 

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Aug 31
0

Is peeling bark on mature Zelkova serrata trees a cause for panic?

By | Trees | No Comments

While working on one strata site recently, one of my tasks was to examine a row of Zelkova serrata trees because the strata council was concerned about two specimens with cracked bark. In the past they had to remove two specimens and now they needed a certified arborist to take a look.

Zelkova serrata

My first encounter with these trees was on the West Coast of Japan in Niigata City, Niigata prefecture. Now I was examining a full row inside a strata complex.

Zelkova serrata is a good street and shade tree with attractive bark and great fall colours. It tolerates pollution and it’s adaptable: it can handle heat, little water, various pH soil levels and nutrient poor soils. That’s not a bad list for an urban tree.

It grows to around 30m high with a short trunk which divides into many upright stems forming a round-topped head.

 

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Zelkova serrata

 

Leaves

The leaves are alternate and serrated thus the specific epithet serrata.

 

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Bark

But what about the bark cracking on mature trees? It looks like the tree is falling apart and possibly diseased. And I had to look this up because I had no clue.

 

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The red bark below is attractive but you can see how residents could easily panic when they come home to trees with cracked bark. It turns out Zelkova serrata trees do this as they mature but I don’t recall seeing it in Japan. Probably because I was paying attention to where I was going on my bike.

On one specimen the orange bark seems to be missing, exposing the wood below. I have yet to figure out what the cause may be. It may be purely academic anyway because the strata council is asking for replacements. They are asking for trees that reach smaller mature height.

 

Aug 24
0

How to please Block Watch with your pruning

By | Pruning, Security, Trees | No Comments

It’s always a good idea to ask yourself why you are pruning. In this blog post we’ll examine pruning ordered by Block Watch.

I’m not completely familiar with Block Watch but I know that volunteers keep their eyes open in their neighbourhood for any suspicious activities. And that includes overgrown trees and shrubs where they cause obstruction issues, block lights at night and could potentially provide cover for criminals and perverts.

So that’s how I ended up pruning two frequently used staircase areas.

 

Dogwoods

 

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Before.

 

This isn’t anything shocking at mid-season. The shrubby dogwood (Cornus) is encroaching into the walkway so I simply power-sheared it back into submission. Now all passersby can get through unmolested by vegetation and any criminals lurking in the shrubbery should be easy to spot. There are also several daylilies (Hemerocallis) that now have some room like the one visible in the bottom left corner.

Since it’s a bad idea to put power-shears in the ground, use hand snips to fix any missed and protruding branches. The same goes for any ugly, shredded stems. Proper raking and weeding should be done before a courtesy blow.

 

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After shot before clean-up blow.

 

Sumac

 

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Before.

 

Again, this doesn’t look so bad unless you use this staircase at night. The sumac tree (Rhus typhina) blocks light from reaching the stairs.

So I pruned branches away from the light pole and from above the stairs. But there was a lot more to do here.

Sumac likes to send suckers up so I had to hunt them down and remove them because the last thing we need here is more mature sumac trees. I also removed dead branches.

Then I snipped roses and Rhododendrons, plus I pinched off the old spent flowers for a cleaner look. It’s a time consuming activity but it can be done on smaller specimens to achieve a cleaner look. Just make sure you don’t pinch off the new buds.

Weeds and cultivation were the last things on my list before end of the day clean-up blow.

 

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After shot. The lamp is clearly visible.

 

 

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Rhus typhina distinctive flower spike.

 

Always ask yourself WHY you are pruning. This blog post shows the importance of clear high-profile staircases and night time light penetration.

Aug 08
0

How aphids get tulip trees in trouble

By | gardening, landscape maintenance, Trees | No Comments

I don’t normally buy the Vancouver Sun because they discontinued their garden column but a story last Friday caught my eye. The title read “Aphid secretions shower property with sticky goo.” Friday, August 3, 2018 Vancouver Sun.

The problem

I have some experience with this issue so I had fun reading about this East Vancouver case. Every summer aphids descend on tulip trees (Liriodendron tulipifera) and feed on their leaves. But since aphids can’t process sugars, they secrete them and the sticky honeydew lands on cars, driveways, etc. The affected couple in the story complained about having to wash their car and their difficulty of moving their baby carriage. The sticky honeydew also attracts wasps which freaks out most new parents.

 

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Tulip tree leaf underside covered in aphids.

 

 

The City of Vancouver allegedly once brought them ladybugs, the aphids’ natural predators. This is what amazed me in 2017 and inspired me to pen a blog post about it: people paying after-tax dollars for ladybugs in the store and releasing them on their trees. One major issue is telling the ladybugs to stay on your tree. Because they move around it’s not an effective tactic.

Solution?

In the past, the couple in the story purchased their own ladybugs “but it made little difference”. So now they want the city to spray or remove the tree. I believe that would be very harsh treatment for this beautiful tree because aside from the many ecosystem services it provides, it also has beautiful flowers.

Luckily, the City of Vancouver knows that removal would cost $1000.00 per tree plus extra costs for replanting. There isn’t enough budget for projects like this which is good news for the tree.

 

Conclusion

While I understand the hassle of sticky honeydew, let’s remember the many ecosystem services trees provide for free. I especially love the tulip tree flowers which come out as the trees leaf out. Complete removal because of aphids would be horrible. Perhaps a picture of one tulip tree flower will distract you from aphids and city help lines.

 

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Liriodendron tulipifera flowers steal the show.

 

May 22
0

When you have to top natives for size control

By | Arborist Insights, landscape maintenance, Trees | No Comments

I hate topping trees and so does the International Society of Arboriculture (ISA); they even publish pamphlets detailing why the practice of tree topping is bad. This blog post, however, shows two cases where topping was somewhat justified and forced.

It was forced because a) the strata client insisted that it be done and they pay the maintenance fees so all you can do is attempt to educate them and, b) the natives in question threatened to overwhelm the spaces they occupy.

 

Salix discolor

 

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Before height reduction, Salix discolor. Note its landscape use close to woodland in the background.

 

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This is our native willow and it’s technically a shrub. In this setting it’s used as woodland margin shrub. But there is one problem. It reaches 7m heights quickly and the owners don’t want to see it from their upstairs patio, preferring instead to look at the tall native Douglas firs (Pseudotsuga menziesii).

So I went in with an extendable chain saw, pole pruners, a ladder and my best friend, a Japanese hand saw. Remember, most tree work can be done with a good hand saw.

The idea was to bring the willow height down and it went fairly well although I was a bit frustrated with some of my cuts. The willow is very soft and if you fail to finish your cuts briskly then you risk bark peeling below your cut. But considering that this is a native shrub, I expect it to shoot out again after my assault.

 

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After picture.

 

 

Acer macrophyllum

 

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BC native Acer macrophyllum with 5 lobed leaves (3 lobes dominate). The leaves are, well, big!

 

I wasn’t very happy about being sent in to top a maple tree but what do you do when the backyard belongs to the in-coming strata president? One look at his backyard made me wonder if the big leaf maple (Acer macrophyllum) was planted or simply drifted in. If you could look to the right you would see giants of the same species in the woods. There the maples are left alone and they reach the regular 30m tall, 25m spread dimensions.

 

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There is not enough space for this native species which will reach 30m without topping.

 

Here it is clearly not the right tree species so topping it is somewhat justified except, of course, the tree will grow again and I have a feeling I will get to know it intimately as the seasons pile on.

Most of the work was done with a pole pruner with the exception of the biggest leader. That required a saw and some care because there is a planted garden under the tree.

The owner was happy with my work (of course!) but all I was thinking about was how the tree did not belong there.

 

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After topping picture.

 

 

Conclusion

Tree topping is a horrible idea but in some cases it has to get done. Please try to avoid it as much as possible. The big-leaf maple above will grow again which means I will get called in periodically to bring it down. The same is true for the willow which will eventually reach the upper patio sight lines.

 

Mar 23
1

Basic tree maintenance techniques for landscapers: 3-point cut

By | Arborist Insights, landscape maintenance, Trees | No Comments

There are many key landscape maintenance techniques all landscapers should know well. I try to teach these techniques to our new company recruits; and home owners can benefit as well from knowing them. Trees are an important component of our landscapes and must be maintained properly.

 

Three point cuts

This is a basic technique all landscapers must know. ISA certification is not required, although I always recommend it to workers with 2-3 years of field experience. This 3-point cut technique does appear in the Certified Landscape Technician practical testing module on pruning. However, you just have to tell the judge how you would make the 3-point cut because they use one tree to test all candidates.

For now, let’s stick to basics.

Yesterday I was at a site doing normal winter maintenance. I finessed beds, blew leafy piles and then I ran into Magnolia trees that were clearly encroaching on a staircase. So I took action because I had time for it and I also enjoy the work.

To remove an unwanted branch, you must use a 3-point cut, unless you’re removing a smaller branch that could almost be taken off with hand snips. Why 3 point? Because first you have to take off the weight of the branch. If you don’t you risk bark damage.

 

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(1) Undercut (White arrow)

Make a decent undercut without getting your sharp hand saw pinched by the wood.

(2) Second cut (Green arrow) to take the weight off. See how cleanly the branch shears off. If you attempt to make just one cut at the branch collar (Orange arrow) you risk ripping off the bark.

 

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The first two cuts are completed.

 

(3) The final cut happens at the branch collar (Orange arrow). We give the tree a chance to cover up the wound. Just make sure you don’t cut into the branch collar.

 

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The branch collar is clearly visible.

 

 

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All done!

 

The problem with stubs

Leaving a stub means the tree can’t properly heal the wound by closing it over. The stub dies anyway but it could allow diseases to enter the tree. So make proper cuts without leaving stubs.

 

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Acer griseum with a stub.

 

This cut was poorly done. The stub is clearly dead and you can see how the tree tried to cover up the wound. You wouldn’t believe how many of these cuts I see in the field. Sometimes the dead stub just breaks off.

Once you learn the 3-point cut, it will become automatic with practice.

 

Dec 29
0

The case of struggling paperbark maples

By | Arborist Insights, Trees | No Comments

I got to see a number of our sites before Christmas because the regular foremen were on vacation. It’s always nice to get a fresh pair of eyes on site, especially before the holidays. Everything must look perfect for the holidays.

One site in White Rock stood out because of its many paperbark maple trees (Acer griseum). They look awesome thanks to their peeling cinnamon coloured bark. So I was stunned when one of my helpers started rubbing off the peeling bark as if the tree was diseased. He clearly preferred a smooth bark look but I doubt the tree appreciated the assault. I told him to stop.

Every paperbark maple on site looked great until I turned the corner into a dead end surrounded by cement walls on three sides. Here we had two specimens of the same maple species and they were clearly struggling. Why?

 

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A) Lack of light. Trees require sunlight for food production and the setting here is horrific. Since there are cement walls on three sides, this is a shady corner. It’s not a great place for these maples to thrive. And the same goes for the grass. It, too, could benefit from more light.

 

B) Competition. We already know that young trees planted into turf struggle with competition for resources. And they often lose. If you must plant trees into turf areas then establishing tree wells around them to help them. The tree wells channel water and nutrients into the root zone and they keep machines away.

 

C) Conflicts with machines. If you zoom in, you will notice bark damage at ground level. I say it’s line edger damage. The kind of damage that could be prevented with plastic tree guards or by establishing a tree well around the tree.

Repeated hits can kill the tree. Here it looks like the trees are using precious resources for repair and stress mitigation instead of growth. Thus the struggling look exhibited by these two specimens.

One other possibility is digging up the trees and moving them to a sunnier location away from lawns. The cement walls could be covered by climbing hydrangeas which are already planted on this site.

 

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January 2018: sporting a new tree well.

Dec 10
0

Frosty plant identification

By | Species, Trees | No Comments

It was fun to observe some of our common plant species covered in frost. How many of them do you recognize? I suggest you look up any that are new to you and learn more about them.

 

Acer ginnala (Amur maple)

 

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Viburnum davidii

 

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This is a common landscape shrub in the Lower Mainland. The berries are attractive. Hand prune when required. When it’s this frosty, just enjoy the view.

 

Skimmia japonica

 

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Symphoricarpos albus (Common snow berry)

 

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This is a native species and birds love it.

 

Imperata cylindrica (Japanese blood grass)

 

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Hydrangea

 

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Some people deadhead their Hydrangeas and use the flower heads in vases; some people leave the spent flowers on so they have something to look at in winter.

 

Crocosmia ‘Lucifer’

 

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This perennial should have been flush cut at ground level weeks ago. I don’t find it attractive, even when it’s covered in frost.

 

Gaultheria shallon (Salal) 

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Liquidambar styraciflua (Sweetgum)

 

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This is a common landscape tree and a nice alternative to maple trees.

 

Parrotia persica (Persian ironwood)

 

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This is an attractive landscape tree with great fall colours.

 

Cotoneaster salicifolius var. floccosus (Willow-leaf cotoneaster)

 

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Ophiopogon planiscapus ‘Nigrescens’   (Black Mondo grass)

 

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What plants did you notice on your walks and in your own gardens?

Dec 08
0

How to pimp out your boulevard tree wells

By | Arborist Insights, landscape maintenance, Strata Maintenance, Trees | No Comments

Sometimes you look out on the boulevard at your strata site and the tree wells look a bit tired. But it doesn’t have to be that way. With some tools and a bit of soil amender you can quickly pimp out your tree wells and make them look great before the holiday season hits.

 

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This looks a bit tired.

 

Step 1

First we grab a nice sharp spade and we deep edge the tree wells. The spade must hit the edge at a ninety degree angle. Nothing else will do.

As for the depth, it should be deep enough to anchor the new soil that’s coming in but not too deep. We’re not building ditches although I have created some ankle-busters in my past. Soil conditions will sometime dictate the appropriate depth.

 

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Acer griseum tree well. You might as well remove the tree guard.

 

Step 2

I know, most people dread this step but we have to weed the tree wells nicely. Use a good cultivator and when you remove the weeds also grab the chunks from step 1.

 

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Nice and clean. The ground was a bit frozen so weeding was a challenge.

 

Step 3

Next, install good quality soil amender and pile it on nicely. Remember, it will settle so don’t worry if the tree wells look a bit puffy. This step gives you an instant upgrade because the fresh black soil looks great!

Warning: do you remember what a doughnut looks like? That is exactly what the soil around your tree should look like. Find the root flare and make the new soil level with it. Then build it up and taper it off as you hit your new deep edge.

Why? Because piling soil above the root flare leads to problems. For some reason, people love building soil pyramids at the base of trees. But it’s a common mistake. The bark above the root flare isn’t supposed to be in a dark, damp environment and it can over time rot. This in turn invites disease in.

Another potential problem is adventitious roots developing above the root flare inside your soil pyramid. There the roots start to circle and they can over time girdle the tree.

So remember, don’t create soil pyramids. Think doughnuts!

 

Step 4

The last step involves clean-up. Especially the grass edges of your new tree wells. Blow them off gently.

That’s it. Now your clients can enjoy beautiful boulevard tree wells on their Christmas holiday walks.

 

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All done! Weeded, edged and top-dressed. This is my kind of tree well.

Sep 29
0

Bronze birch borer related pruning

By | Arborist Insights, Trees | No Comments

Because I am ISA certified, tree-related tasks are automatically given to me by default. And that’s fine. This blog post is about a birch tree which exhibited top dieback. So I was sent in with pole pruners and an extendable Stihl chainsaw to take care of the request.

 

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It’s not super clear but the top leader is dead.

 

Once I took out all of the dead branches, I pruned the live parts of the tree to give it some sort of shape. Then I hauled out the debris up to the road for later truck pick up. Only later did I realize that my boss expected me to take the whole tree down! Not my style anyway.

Since we suspected the cause of the dieback to be the bronze birch borer (Agrilus anxius) my approach was correct. Pruning out affected limbs is the way to do it. I just couldn’t burn the diseased branches on a strata site surrounded by woods. My only hope is that no adults emerged before the debris was processed with other green waste.

Bronze birch borer

Adult bronze birch borers are half an inch long and have slender dark green bodies with metallic bronze sheen. In summer, females lay their eggs in bark crevices of weak and stressed birches. They prefer sunny, south facing branches.

Larvae hatch 14 days later, enter the bark and feed on sapwood. After one or two years adults emerge by chewing D-shaped holes in the bark.

Signs

So let’s review. Bronze birch borers cause treetop dieback, leaf wilting on branches and D-shaped exit holes in the bark

What can we do?

Since the bronze birch borer only picks on weak and stressed birches we should keep our birches in good shape with regular watering, feeding and pruning. Also, put your birches in shadier corners.

One other idea is to plant birch borer resistant river birch (Betula nigra) cultivars.

If you are lucky, you will get some help from natural allies like parasitic non-stinging wasps and woodpeckers.

The birch featured in this blog post is still alive and standing.

 

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After removing all dead branches and pruning others to give the tree some sort of natural shape.

 

Source: GardenMaking magazine no.30, pp.56 and 58.