Why Knot?


Image result for images of black knot disease Mature Black Knot

In recent years the spring season in Calgary has been windy and wet, two prime contributors to the outbreak of black knot disease in the city and surrounding areas.  Owners and potential purchasers alike are in a fever pitch about the unattractive fungal overgrowth affecting their landscapes.  First let me give you the good news.  Black knot is not fatal in most cases.  Like the flu, if the individual is weak, and symptoms are left unchecked, death can occur, but rarely is it the case.  What is most distressing about black knot is how easily, and widespread it can occur, and how truly ugly in appearance it is.

You know what I am talking about, that “poop-on-a-stick” you see all over the park and neighborhood trees.  What you are seeing is called a gall, and by the time it is black and highly visible it is 2-3 years old and ready to spread ascospores to susceptible trees within the prunus species.  Caused by Apiosporina morbosa, or Dibotryon morbosa (same fungus, different names), it is an airborne fungus that requires wind to spread, and moisture (rain) to stick to the tender new growth on the tips of branches. This new growth is the only part of the tree that can be infected each year.  This is good news, as it provides a year to year and a half window of opportunity to prune, and therefore control the spread of black knot.  Galls begin to form the first year and become visible in the fall or early spring of the following year.  They are small, and green, to light brown in appearance.  This is the time to prune as the spores are not mature and viable until the gall is 2-3 years old.

Image result for images of black knot disease Immature Black Knot

When pruning the immature gall, cut 8″ below the knot, and disinfect your pruners between EACH CUT with a 1:10 solution of bleach and H2O.  If you are pruning a mature gall, some arborists recommend 12″ below as the fungus may have extended through the branch itself.  Be sure to burn or bury the branches immediately after pruning.  Spores can live in a pruned branch for up to 4 months.

Image result for images of black knot diseaseBlack Knot on trunk

In some cases black knot will appear on the trunk or other critical juncture on the tree.  In this instance, hire a certified arborist to remove the damaged tissue.


The best way to control black knot is to prune diseased branch tips as soon as evidence of the disease it noticeable.  Do not prune unaffected branches, or you will lose all your fruit bearing capacity for the year!  Be sure to check your Nanking Cherry,  Sandcherry, and flowering plum shrubs along with Mayday, Schubert Chokecherry, Amur Cherry and Sour Cherry and Plum trees for immature, green galls.

The winter here has been so mild and warm, creating a perfect window to eradicate black knot before the spring season.  I encourage you to prune on the next double digit day.  The spores that carry black knot fungus are spread throughout the blooming period and up to two weeks after. Best to rid your trees of black knot before it can spread.  Good luck!


What Happens When………..you start seeds indoors too early.

Scarlett, the runner bean, hurries to catch up with her cousin Audrey………..  I woke up one morning to find my runner beans gearing up for a marathon.  I got a little too excited to sow indoors last year……

Don't be tempted to start your indoor seeding too early......
Don’t be tempted to start your indoor seeding too early……

Snow Damaged Trees and Shrubs

What a week of crazy weather we have had here in Calgary! This morning minus 4, next week, 22 above. Welcome to gardening beneath the arch, or as it is most commonly referred to as The Chinook Zone. One thing we can always predict, is the unpredictability of the weather here in Cowtown and surrounding regions. This freak snowstorm has wrought havoc with electrical lines and caused considerable damage to many trees and shrubs. I just wanted to take a minute and talk about what you can and should do regarding any damage to your landscape. I have learned on the job just how attached owners become to their trees. I can relate as I have lost a 20 year old tree in this mess myself.

So, what to do? First take a careful inventory of damages. If you live in an area where the power lines are above ground, please make sure that the area is safe and no lines are down. Elms, poplars, and evergreens typically experience the worst damage. If there are loose and dangling branches, exercise caution walking below. Resist temptation to just tear down any dangling branches to avoid further injury to the tree. If the tree is young and you have the tools, prune judiciously, bearing in mind what the tree will look like in a couple of years. Plan your cuts as much a possible to help the tree grow back into a pleasing shape. This could take a couple of years, depending upon the damage. If your damages are extensive; broken leaders, branches that very long and heavy, requiring more than one cut, please call an arborist to assess the viability of the tree and to execute the pruning. You are more likely to save the tree with the help of a professional who can brace and cable branches if necessary.

Down n Out
Down n Out

Stand back from your tree or shrub and gently loosen snow with a broom. You don’t want a branch to fall and knock you out in the process! Check evergreens carefully, as their damage is not as evident, the damaged branch remains green and you would not notice it until spring. Damaged trees and shrubs are more vulnerable to disease and therefore it is wise to take care of pruning as soon as possible. In some cases, arborists are able to save branches and leader trunks if the repair occurs before the wood dries out.
Do not use pruning pastes after cuts- they can actually impede the healing of wound. If you are uncertain whether to paste, check with an arborist.


Most woody perennial shrubs can bear a severe pruning if necessary, but one third of the current growth is safe for all, and can spur some rejuvenation, which is actually good for older shrubs.

Next week, when the temperatures return to normal, you will find most of your landscape will as well. Don’t be too quick to dispose of trees and shrubs that are damaged. Work with them and you will find most will come back next year none the worse for wear. In the meanwhile, visit YouTube and check out some of the great pruning video tutorials, sharpen and oil your pruners, and start planning next weekend’s BBQ!
Calgary is offering free disposal of branches at its landfills. Thank You City of Calgary.

Shakin’ things up- Bees n’ Butterfies

When it comes to biotic pollination the bee is king (or queen) as the species would have it.  They are undisputedly the most prolific for sharing pollen amongst their peers which include birds, moths, wasps, and yes, butterflies. When working in the garden I really noticed first hand how my plants would shake along with the intense buzzing sound coming from the bumblebees.  There is a reason for this.  Bombus (unlike Apis, honey bees), contort their thorax to enable them to gather more pollen from the plant as it sticks to the surface of their bodies and then is released onto the next flower they visit.  The honey bee does not have this capability but still manages to get the job done. This process is called Buzz Pollination.

Butterflies pollinate also as they artfully flit about, using their feet to taste for suitable plants on which to lay their eggs.  Butterflies can see the colour red, which other pollinators cannot differentiate and are attracted to warm coloured plants in yellows, oranges and reds.  They need a large leaf and prefer clustered blossoms upon which to perch.  They gather nectar with their long tongues and deposit pollen as they walk about the plant.  When they find one that is suitable and the time is right they will deposit their eggs on the underside of the leaf to give their caterpillars an immediate source of sustenance. Ever notice how many butterflies you see in a meadow or other native space?  That is because they prefer native flowers, although my garden is a testament that they have cousins who prefer the urban lifestyle.

To attract bees to your zone 2 garden plant borage, catmint, hyssop, chives, lavender, mint and lemon balm.  You will get to enjoy these also!  Currently I find my Sedum ‘Autumn Joy’ a welcoming host while there are not a lot of other things blooming.  Butterflies are partial to asters, sedums, lantana, marigolds, lupins and monarda.  They also gravitate to aspen, birch, cherry, oak, and willow trees. Why is it important to help and encourage our pollinating friends?  Over 90% of plants require a pollinator to propagate.  Enough said…….

The Saskatoon Farm

ImageImageImageImageToday theyardtherapist rambled a little further south toward Okotoks, AB and stopped into The Saskatoon Farm for a little lunch and to pick up some fresh from the earth vegetables. I have been out many times this summer to sample the menu at the cafe and to purchase produce and neat little items from the gift shop which carries unique jewelry, art, kitchen gadgets, baking and so much more.  Today I toted my camera to take you along with me to enjoy the sights of a true working farm and garden center.  I have been fortunate to be able to ride horseback through the mountains of Utah and study up close the flora of the SW uplands as well as hike through botanical gardens from Halifax to Puerto Vallarta and then to Vancouver Island, but I have to say that nothing I have seen has diminished the beauty of the summer in the prairies this year.  The farm had the most stunning mass planting of Amaranthus caudatus (Love lies bleeding) I have ever seen.  Never one of my favorite plants in the past, they have managed to convince me that it is a new must-have in my garden.  The Saskatoon farm cafe is open year round and if you like buffalo, or would like to try it I recommend you try it here.  The farm features a buffalo jump (no longer in use of course) which offers you a pretty view to the river.  The vegetable stand is reasonably priced and the produce truly freshly picked at its peak.  I make a trip out at least once a week to get whatever is in season, the very best way to cook and to eat.  So join me for a little stroll around the farm and get out there yourself whenever you need a break from your day to day.  (Who doesn’t need that!).  Enjoy!Image

A Day In the Countryside

Today The Yard Therapist went rambling around the countryside in search of a P.nepalensis ‘Miss Willmott’.  After checking at a few garden centres I found myself just outside the  Calgary southern city limits at Countryside Landscaping and Garden Center in well, the countryside.  From the moment I parked in the lot I knew I was in for something special.  Now this garden center doesn’t just sell plants, it shows you how a lush and gorgeous garden is created and what aImage joy for the senses it can be. From the entrance to the perennial shop it is a one beautiful example after another of what YOUR garden can be like with proper thought and care.  Charming courtyards and a luxe outdoor kitchen, of which they would happily design for you, along shade dappled paths remind you of why you garden or why you would want to in the first place.

Kim has a special talent for terrariums and they have a full stock of essential items in-store.  She let the cat out of the bag that they will be running workshops on this popular revival of a Victorian indoor plant display coming soon.  You can learn more about Countryside at www.csgcl.com/.  I recommend you drive out and take a look around.  And by the way, they had my ‘Miss Willmott’!  I had given up hope!ImageImageImageImage

Drip-lines (not the kind you hear at the bar or your cousins wedding)

What IS a drip line and why should you care?  The term drip line refers to the area surrounding a tree or shrub where water absorption is at its greatest potential, the farthest extension of its lateral roots.  Ever see your neighbor (who may or may not be a drip) in his bermuda shorts, socks and sandals mindlessly watering his tree trunks or maybe you have done this yourself?  Unfortunately naughty one, this is will not greatly benefit your tree and is a terrible waste of precious water.  A good way to gauge a drip line of any tree or shrub is to determine the farthest branch surrounding your tree.  The area below is a reasonable estimation of the drip line for that tree so water well and deeply to establish healthy roots (but that’s another story)….and know you are managing water resources wisely.