Plant Lady: You’ve got questions about pruning fruit trees; we’ve got answers
The time to prune most fruit trees is when they have dropped their leaves and before buds open in spring.
Pruning in the dormant season is ideal because of two reasons: you can easily see the tree structure and it encourages fruit production for the upcoming spring season and fruiting wood for future seasons.
Let’s focus on fruit trees that are at least 3 years old — trees with their main scaffolding branches formed. I’ll discuss pruning younger trees in a future article. The goal here is to cover the basics of pruning. These are the techniques I successfully employ with my fruit trees. I am going to focus on methods promoting an open center (think of a tree with a vase shape). This is an architecture which works well for all fruit trees.
On all fruit trees the first step of pruning is to remove broken or dead branches. If not sure if a branch is dead, scrape it lightly. A viable branch will have green tissue directly under the bark. Second, make sure to remove any suckers — these are branches coming directly from the rootstock.
What’s the rootstock? Most fruit trees are grafted onto a different root system to facilitate better growing performance. The rootstock is anything below the graft line. If allowed to grow, suckers from the rootstock can sap energy from the grafted variety (termed a scion).
Now that initial pruning is done, we’ll move onto the next step, thinning cuts.
Ideally, trees will have a structure with three to five equally distributed main branches, forming a vase shape. These scaffold branches should be shaped in the first three to five years of the tree’s life. Thinning cuts remove an entire branch back to the scaffold branch, or to another branch larger in girth than the one being removed.
The Goal is to have 6 to 12 inches of space around each branch, yielding an open, evenly spaced canopy. This allows sunlight in and promotes air circulation. Both increase fruit production and decrease pests and diseases.
Leave branches which are either growing parallel to the ground (horizontal) or up to a 45 degree angle (upwards) — try to leave equal numbers of each.
Horizontal branches tend to be fruiting this season, and upwards branches are your future fruiting limbs.
Branches growing at angles of greater than 45 degrees (more vertical) can break with heavy fruit.
Remove branches growing inwards (toward the trunk).
Remove branches growing downwards — these rarely fruit.
AGE OF WOOD
Before going to the next step, we need to consider the age of the branches.
The age of fruiting wood — the branches that will produce fruit — varies amongst fruit tree species.
To tell the age of a branch you can look for color variations. Currentyear wood will be green, generally, second-year wood will have more of a reddish-brown color, followed by older wood being more brown and barkcovered.
This color chart works very well for most pruning. For those looking for a higher-resolution technique to determine age, you can look at bud scale scars, which are laid down each year. If there is interest in this, let me know and I will do a future article on this method.
With the thinning cuts done, the tree has a desirable structure. Heading cuts shorten remaining terminal branches — those without other branches (longer than 6 inches) coming off them. These cuts are going to promote vegetative growth and fruiting.
Cut directly above a bud, leaving about ¼-inch of stem. If you leave any more stem, the tree will have a hard time healing.
Prune back to a bud that is facing the direction you want the new branch to grow. In other words, cut to a bud facing outwards and upwards.
Below is a guide to which groups of fruits produce on different ages of wood. This will guide you as to which age of branches to prune and which to leave to ensure optimal fruit production.
These form fruit on branches grown in the previous year (1-year-old wood), which will have a reddish color to it.
Goal 1: Remove enough wood more than 2 years old to renew growth for future seasons.
Goal 2: Keep enough 1-year-old wood to have fruit for the upcoming season.
Rule of thumb: Remove about 50% of last year’s growth (1-year-old wood).
APPLES, PEARS, CHERRIES, PLUOTS, PLUMS
Form fruit on wood that is 2 years old or older, which will be brownish with bark.
These trees have fruiting wood that can remain productive longer than peaches/nectarines (up to 10 years).
Rule of thumb: Remove about 20% of last year’s growth.
ASK THE PLANT LADY
Q: Why are my oranges splitting while on the tree?
A: Splitting of citrus is caused by the plant taking up more water and sugars than the rind can accommodate. Almost always it is due to temperature and water fluctuations. Hot, dry winds late in the season can also cause cracking. The hot winds will pull moisture out of the plant, including the fruit.
When the plant is watered, moisture will reenter the shriveled fruit, causing it to swell suddenly and crack the rind. To prevent this, it is important to keep soil moisture even. This means not allowing the tree to wilt and then water heavily. Also, avoid overwatering late in the season when plants’ hydration requirements decrease.
Dwarf fig trees produce sweet fruit about twice a year.
The Bradford pear’s fruit was meant to be sterile, but when pollinated by other callery pears, it became fertile.