Susan in front of young plum tree that will be cut down….you can’t see it in this picture, but the trunk has been infected with black knot, a disease that could easily spread to the other trees.

When you plant a fruit tree, you start a long term relationship. Fruit trees need to be babied in the first two years after planting. You will give them lots of water, mulch, and prune them annually to help them settle in to their new environment. As you work with your trees, they become your babies. So when one of your trees becomes sick, it’s easy to wait and hope it gets better. But in some cases, with very infectious diseases, by waiting you may be endangering the rest of your orchard trees.

Lynn cuts down young tree with black knot

In Ben Nobleman Park Community Orchard we have 14 fruit trees and three of them are plums. The youngest was planted in 2010. We planted this plum as a “whip” – a year old tree that didn’t look like much more than a branch with roots. Like many whips, the tree adjusted really well to its new environment and like many types of plums, it grew vigorously and within just two years it became as big as its neighbouring plum trees that were older and more established.

At some point, however, our young plum must have gotten a wound on its trunk. While we inspect our trees regularly, we never noticed it, partly because we paint the trunks of our trees white as a way to repel climbing insects. Underneath the white paint, the wound became infected with a very infectious fungal disease called “black knot”. Hidden by the white paint, the trunk grew a corky knot of fungus inside it.

If the black knot was on a branch, we would immediately cut off the branch, seal it up in a garbage bag, and put it in the garbage to prevent the disease from spreading. But what do you do when the black knot has taken over the tree trunk? You need to remove the entire tree and that’s what we did this week.

This tree’s trunk had been painted white to keep climbing insects away. But underneath the paint, you can see brown swelling inside a wound in the tree. That is black knot and it can spread quickly if left in an orchard. If it was on a branch, you can just remove that branch. But here it was on the trunk so we had to cut down the entire tree.

The moral of the story? When you plant an orchard, you invest a lot of love into your trees. You water them, mulch them, prune them, and care for them. But as hard as it is, it is essential to be detached. If we were sentimental and kept the tree – just hoping for the best – we would not only lose that tree, we may also lose the other plum trees in our orchard. The disease could easily spread to neighbouring properties and their plum trees. So sometimes you need to sacrifice one tree, for the protection of the rest.

And so we, the volunteers of Ben Nobleman Park Community Orchard are saying goodbye to our young plum tree.

Next year we will replace that tree with another. But knowing that black knot is a problem in our neighbourhood, we will not replace it with another plum which will be vulnerable to that disease. Instead, we shall start researching another tree to integrate into our orchard – hopefully one that is more disease resistant. Want to know how to research a fruit tree? Susan Poizner will be teaching her “How to Choose a Fruit Tree” workshop at the Evergreen Brickworks on August 11. For more information, keep an eye on this website, sign up for our mailing  list or visit www.orchardpeople.com.