Garden Alert: Poplar & Aspen Borers

One pest that is causing a lot of grief for those who have poplar trees on their properties is an insect called the Poplar Borer.

It is a native beetle that evolved feeding primarily on native aspens, but has developed a taste for Swedish Columnar aspens that are typically planted in rows along fences for privacy screening. Poplar Borers are rather large, gray beetles with faint, yellow stripes on its body and antennae that are as long as its body.

The problem with these borers is that they not only feed on the green “phloem” that sits just below the bark and moves sugars up and down the tree, but the larva (worms) also tunnel into the wood and leave a labyrinth of trails that weaken the tree, leaving portions of the trunk prone to snapping-off on windy days.

Aspen Borers prefer aspens that have trunks about 10 cm wide or larger and they typically seek trees that are stressed. The adults prefer to lay eggs on the south to southwest side of trees that have lots of exposed bark (extra trunk heat is better for larva growth and development).

The lifecycle of Aspen Borers can take several years to complete in our region, but once they invade trees they are very difficult to control. Given the great benefits of having Swedish Columnar aspens, and the expense of removing these trees, the battle to keep the borers at bay is critical.

Here are some of my observations and a bit of a game plan for Poplar Borer:

  • Aspens growing in landscape fabric with rock around the base are the worst affected, typically

  • Drought stressed aspens growing in poor soil are also preferred by the borers

  • Aspens with branches removed on the south/southwest side of tree are attacked more often

Symptoms of borer attack:

  • Small holes in trunk with brown sap stains on bark

  • Small piles of ‘wood shavings’ at trunk base from borer tunneling

What can be done?

  • Inspect your poplars several times during the growing season and look for any signs of damage

  • Pest control products like ‘Garden Protector’ can be used as a trunk and foliage spray prior to the borers penetrating the wood

  • If the borers enter the wood, control is difficult. Success can be found by applying Knock Down aerosol insecticidal spray directly into the entry holes on the tree trunks.

Aspen Borers are destructive pests so if you have Swedish Columnar aspens always be vigilant! Being proactive with controlling the beetles is the best strategy!

- Jim

Eight Varieties, Two Trees

If you’re a bit indecisive or simply like the idea of having a number of different apple varieties on one tree, multi-grafted apples are the answer. 

Just by planting two multi-grafted apples you can harvest 8 different apple varieties and have a continuous supply of fruit beginning in August and continuing right through into October – weather permitting, of course.

One suggestion that I would make is to use metal tags to label the trees, or at the very least, take some notes and photographs of your apples so that you know which apple varieties are which. Most of us believe that we will remember the names of the apples and where they are located on the tree, but – if you are like me – your memory might not be quite as sharp as you think it is from one year to the next!

Multigraft Tree #1

•    Compact variety with yellowish-green fruit that is washed with red. Good for both fresh eating and cooking. Usually ready to eat in August.
•    Light green fruit with red stripes. Discovered in Manitoba and super cold hardy. Great fresh and cooked.
•    Smaller fruit. Pale green striped with red. Good for fresh eating and cooking. From Battleford Saskatchewan
•    Yellowish-green skin with bright red blush and stripes. Mildly sweet fruit. Very good for fresh eating. Matures in late August.

Multigraft Tree #2

•    One of the very best tasting apples. Honeycrisp are juicy, crispy and grown commercially. They are often found on grocery store shelves.
•    This is a hardier cousin of the venerable ‘MacIntosh’ apple. It shares much of the same delicious flavour of the MacIntosh but is tends to be smaller.
•    See above!
•    One of my favourite apples, Norkent is crispy with a great balance of sugar and tartness and is one of the best dessert apples for the prairies.
Heyer 12
•    Heyer 12 originated as a seedling from Russia and serves as the rootstock. It is very tough and produces yellow fruit that is a bit. Excellent for juice and sauce but its main attribute is cold hardiness.

Happy Canada Day!


Every Canada Day, I'm reminded of the rows of maple trees that lined the dirt road on the hillside across the road from our farmhouse.
Dad planted them both for their inherent beauty and because they provided a bit of a windbreak for our strawberry and cucumber patches.
Our maples were Amur maples, not the huge sugar maples whose leaves are featured on the Canadian flag. And while the leaves of our Amur maples lacked the outline of the more stately sugar maples, they were equal to the sugars in developing blazingly red foliage in the fall.
Sugar maples are hardy in our region although they rarely reach the magnificent height of the eastern Canadian maples thanks to our drier and colder climate. However, at maturity, sugar maples are far too large for most yards, while Amur maples are suitable for even the "postage stamp" yards.
Although Amur maple is not an indigenous plant, it is tough, resilient and beautiful. Sounds pretty Canadian to me.
 Happy Canada Day!


~Jim Hole


I had the opportunity to visit a yard that had two espalier apple trees. Espalier is simply a method of training fruiting trees, like apples, to grow in a fan pattern along wires or along a fence. For example, a common espalier technique is to string 4 wires between two solid posts, plant an apple midway between the posts, and then train the branches to run along the wires. Since there are two branches per wire, a total of eight branches are trained along the wires and secured with loose-fitting, foam covered ties.

Espalier is a fabulous way to maximize yield in a small amount of space. Besides, it just looks really cool! The other great thing about espalier is that each leaf has much greater exposure to sunlight, which means that these little ‘solar panels’ are maximizing their output of photosynthates (fancy term for sugars etc.) to the tree’s fruit. Many lower, and interior, leaves on regular apple trees rarely receive full sunlight and therefore are unable to contribute much to fruit development. On the other hand with espalier, virtually every leaf is fully engaged in fruit production.

Espalier is not difficult to do, and great for those of us who love homegrown apples, but don’t have the room for a broad, 15 meter tall tree.

 And if nothing else, for me at least, just saying the word espalier makes me sound a whole lot more sophisticated than I am.

~Jim Hole

You Plant A Tree For Your Grandchildren

About 10 years ago, my neighbour’s spruce toppled in a windstorm and smashed into our fence. The middle section of the fence was obliterated, but at least our house was spared.


These past couple of weeks I have visited a number of homes that have trees with structural problems. One was an apple that had a large branch snap during a snowstorm. A couple of weeks ago, an acreage owner had a poplar topple during a windstorm resulting in a severely damaged roof. Finally, a young couple with small children, were asking me about what should be could be done about their neighbour’s large poplar tree that was leaning, precariously towards their house.   

As a certified arborist, I’ve seen a lot of trees with a lot of problems. While many people tend to focus on insect and disease problems on the tree’s foliage, the major of a tree’s problems (about 80%) originate in the root zone. Preventing a tree from becoming ‘hazardous’ is not difficult if the proper steps are taken beginning with something as ‘simple’ as transplanting. Incorrect planting depth, poor soil, improper staking, and inadequate or excessive watering are mistakes that are often made during transplanting that have a huge impact on trees years later.

As the saying goes, ‘You plant a tree for your grandchildren’. It’s important that they have the opportunity to enjoy it…safely!

~Jim Hole


The "H" Tree

When I was growing up on the farm, we always had plenty of space to grow fruit trees. Dad loved planting trees so we had lots of different kinds of trees around in the yard.

Because we had so much space, Dad planted about 20 different varieties of apples so we had plenty of apples to eat starting with the crab-apples in July and finishing with late maturing apples that were ready in late September and October.


But while we were fortunate to have so much space for growing apple trees, many small, modern, urban yards can only support a single apple tree at best. Yet, all is not lost if you have a small yard and yet want to enjoy a variety of different home-grown apples.

The solution is to plant a single apple tree with multiple apple varieties grafted onto it. We've got one this year that I’m calling the "H" tree.

 Now if you are wondering what the "H" I’m talking about, we have a single tree grafted with the following apple varieties Heyer, Honeycrisp, Hardi-Mac, Harcourt, and Haralson.

So the H apple provides a wide variety of apples to suit everyone’s taste, yet doesn't require a lot of space. It’s the perfect choice for those who have limited space and besides…I just think it’s cool to have so many apples on one tree! 

And, by the way, this H apple also has a "Parkland" apple grafted onto it. Why they put a P with the H’s, I don’t know. 

Maybe the grafter thought the H joke had runs its course.

Before you plant a grafted apple or any apple tree, for that matter, here are a few points to remember:

•    Evaluate the site, and spend some time visualizing what the apple will look like when it is fully grown. If the apple tree is going to block out the sun for your flowerbeds and vegetables, you may want to relocate it, if possible.

•    The apple tree should have at least 6 hours of direct sunlight per day for good fruit production. Shady spots are poor choices for apples.

•    If the apple is planted near the neighbour’s fence there may be a concern with the mature fruit drop. The dropping fruit may be of concern to your neighbour and don’t forget that the best apples might be on his side of the fence. 

•    Always allocate some time in the spring for pruning. Healthy apples with strong branches require a bit of pruning each year.

•    Document the apple varieties so that you don’t forget which are which. Metal tags wrapped around branches (loosely!) are great way for keeping track of what’s what.

•    Prepare the soil properly and have the right tools at hand (shovel, pruners, tree supports, Myke, irrigation equipment, tree trunk wrap, etc.)

~Jim Hole

For more information on which varieties of apple trees (or other fruit) we carry, please click here to see our Fruit List for 2015

To learn more about our Myke 5 year guarantee on Hole's trees, please click here.