One important note: always prune cherries when you will have at least 2 days of dry weather. This can help reduce canker.
Most people grow sweet cherries as freestanding ‘bush’ shaped trees. In a future post, we’ll talk about growing sweet cherries as an espalier or fruiting wall form called UFO (upright fruiting offshoot).
Cherry trees produce stiff and fairly upright branches. Growing cherries as an open center (bush) tree will keep the height down making for easier pruning and picking. These trees will end up wider and paying attention to potential shading issues will be important in maintaining a healthy tree. There are several basic cuts and principles with cherries that you will use over and over. For the most part you are using the same principles as with peaches, you just don’t prune quite so much out on an annual basis.
Keep in mind while reading this that your goal is to prune your trees to keep them healthy- open them to light, to keep the larger wood low in the tree, and to promote fruit wood.
In developing the cherry tree shape and form you will want to develop 3 to 4 main upright branches that will become the main leaders of the tree. Most nursery trees will not have 3 plus upright leaders (shoots). Often a young cherry tree is just an whip with no branches. The first year you will cut the main leader or leaders down to about 20-30 inches. This height will depend on how you are going to maintain the grass around the tree; meaning how much room do you need for your lawnmower. Don’t worry if there is only one or two shoots. Prune them all back and they will give you plenty of choices next year.
Cherries have the propensity to produce shoots that continue to elongate and that do not push side branches. You can’t let this happen! As these main leaders grow in early summer, make a heading cut into the main leaders every 2 or 2 1/2 feet . Or if the branches have grown this distance by August 1 (or anytime before then), pinch out the terminal bud. Continue to do this until the shoot produces several side shoots. Then let the shoot grow another 2 feet or so and repeat the process. If these shoots are not growing vigorously then it is better to wait and dormant prune these shoots. You don’t want any more than four uprights.
In 2-3 years you should have a small but nice sized fruit tree. You could see blossoms on your trees in the second year and certainly in the third year on most varieties.
How do we manage quantity of fruit so we can get good size and high sugars in our cherries?
There are a couple of fairly easy steps to achieving this goal. Both factors we will talk about have to do with ways to thin fruit.
- The first way is something you can do at pruning time: Tip the new growth from last year by roughly 25%. All the buds you left last year on that shoot will turn into flower buds and, with pollination, fruit in the second year. Go out and before you prune, count how many buds are on several of your one year shoots. Typically you will see nearly half the buds are in the top 25% of the shoot. So by tipping 25% of those shoots you have already reduced your crop by 30-50%. Cherries grown on Gisela rootstocks are very heavy bearers, and must be thinned by 50% to 75% in their ‘on’ years. You will see in the photograph an example of pruning one year old shoots . Cherries bear fruit at the base of a one year old shoot as well.
- The second technique for maintaining quality is stripping off all the spurs on the underside of the branch. Remember this should only be done when the weather is dry. By taking these spurs off, you have providedthe necessary air space for the cherries that will hang of either side of the branch. Another advantage of this method is removing the fruit that is most likely to rot in a wet year.
- So, you’re out in your yard, and looking at your cherry tree, you see a lot of vigorous, upright shoots. Upright shoots generally produce the largest fruits and the most sugars. If there are too many shoots, it is worth thinning these spurs by hand as long as you followed the above instructions and have tipped your one year old shoots.
3-4 leaves per fruit is what is typically considered a successful ratio in commercial cherries. Because cherries ripen so early they need a little better management to produce larger and sweeter fruits. This is because the fruits are ripening just as the maximum growth spurt is happening in the tree.
If you are working with older trees you should consider making some heading cuts into the 5-6 year old wood. As any cherry tree ages this will be a key practice to renew old wood with new wood that is closer to the trunk of the tree. The best fruits are grown on 2 to 4 year old wood. Cherry spurs are fruitful for many years; however by renewing branches every so often you can maintain tree size, vigor and quality in these productive trees. These renewal cuts are back in towards the trunk on the branch. You find side shoots that have 1-2 year old shoots and make the cut back to that point. For best results just prune out one of two of these aging branches a year. The tipping of the one year old wood described above should be done here as well.