Why Does my Tree Only Bear Fruit Every Other Year?

Last summer someone wondered aloud to me that there were not many wild flowers. This year, walking through the forest and wild meadow on the way to the orchard flowers are exploding from the ground, trumpeting life and the air buzzes with insects. I knew that 2016’s drought was a heavy one for our area, but the stark contrast with 2017’s wet spring is shocking.

My fruit trees are growing like fireworks, currant bushes I planted as twigs in May have quadrupled in size. The blueberries I planted this spring have already outgrown the ones that struggled to survive the dry summer. The grass last July was brown and flattened against the earth, now it makes a solid green curtain reaching my navel. It has turned the orchard into a maze where I have to guess the general direction of my Honeyberries to find them. The grass is taller than most of my berry bushes, but they don’t seem to mind. They all have a small radius where I have weeded and mulched the 'root zone'. After all the rain we’ve been having and my application of manure last week the orchard is singing. A monarch butterfly flutters past, floating above the tall grasses and flowering milkweed.

This week I’d like to address a question sent by a reader asking why their apple tree did not flower this year. I commonly get asked about this sort of fruit tree behaviour. The alternate version of the same question is: Why does my fruit tree only bear fruit every other year?

Trees run on a two year cycle when it comes to flowering. Trees want to produce fruit and seeds in order to create offspring. Imagine this year your tree is not producing any fruit. It is going to put a lot of energy into creating flower buds which will be able to produce fruit next year. Fast forward to next year, the tree is loaded with pollinated flowers and it is using all of its energy to ripen its immense load of fruit. This means that during this second year the tree has not been able to invest energy into next year’s flower buds. Year three we are back to a tree with no fruit.

In commercial orchards farmers control the fruit set by spraying the trees (in both conventional and organic agriculture this is a permitted practice, though the chemicals and techniques differ) in order to make them drop two thirds of the potential fruit load. This means the apples, or peaches, or plums that are left on the tree will ripen bigger and more flavourful.  At the home scale you can thin fruit by hand and ladder. My second year working in agriculture I spent a few days in spring thinning fruitlets on peach trees in a greenhouse in northern Ontario.  It is a slow process, but it improves fruit quality and ensures a harvest for next year.

Once trees have gotten used to biennial bearing, it is very difficult to restore them to annual bearing. As far as I am aware it is not impossible, but the ease at which you can bring those trees back is largely affected by how long they have been allowed to bear fruit in this way.

Your berries won't need thinning, they are pretty good at self-regulating. You should thin your grapes to improve flavour. The amount of grapes you leave on depends on the vineyard, the use for the grapes (wine or fresh eating), and the climate. Go with your gut, trust your instinct. Often when it comes to plants the power of observation will lead you to the right place.

Hoping you enjoyed a lovely summer solstice, have a lovely week.

-E.V.