In 2015, we selected six ‘very hardy’ varieties of pear from St. Lawrence Nursery to find out how they grow in North Dakota and planted two of each at 15’ x 20’ spacing.

In typical loam soil, these trees will really grow. I try to prune these lightly; not as much as an apple tree, because pruning just invigorates growth. Pears can grow into very large trees. In 2019 and 2020, when the trees grew as high as I could reach on a ladder, I cut back the leaders to a side branch. We will see if this was a good idea or not. If you want to grow pear trees (you typically need two varieties to get fruit), I recommend that you love pruning.

For the most part, the trees grow with narrow crotch angles. I use wooden lath to make spreaders and these trees end up looking like art projects, according to my husband. Some of the varieties produce water sprouts that can grow five feet in one season. I remove these but try to leave other branches that I normally would have removed in an apple tree. I also cut back by half some of the branch tips that have grown 2-3 feet. I want to make sure that we get sort-of compact growth. Sometimes I do this in spring. Sometimes I try it in summer.

Using spacers to create better branch angles.

One variety, ‘Ayers,’ failed after several years due to cold injury and I removed it. The precocious (fruit-bearing at an early age) variety, ‘Schroeder Hardy ND’, had fruit in its third year (just 3) and has produced every year since. One of two trees of the remaining varieties all had some fruit this past year, although ‘Patten’ had just one fruit.

With pears, you have to pick the fruits when they are ready but not ripe. This means watching and then picking the fruit when it reaches a certain stage: generally, when the fruit color changes from dark green to light green and the lenticels turn brown. Then that fruit is stored in a way that the starch granules can change into sugars. For ‘winter’ pears, like commercial ‘D’Anjou’, this means three months of cold storage before they can ripen at room temperature. For summer pears like ‘Bartlett’, it takes just three weeks of storage. (Therefore, never buy US ‘Bartlett’ after Christmas or ‘D’Anjou’ before.) The tricky part is finding out the proper storage conditions. Is it in the refrigerator, or ‘cool’ temps, or room temp? And for how long?

Pears in August

So far, I have not been able to figure out how to ripen ‘Schroeder Hardy ND.’ It spoils from the inside out every time. There was no chance to figure it out for the other varieties this year either – a very windy night on September 2 caused all the pears to fall off the trees before they were ripe. I’m afraid that this will be a problem in North Dakota – that the stems connections are very brittle and the pears easily fall in the wind.  We’ll know more after 2021, I hope.

Kathy Wiederholt
Kathy.Wiederholt@ndsu.edu
Northern Hardy Fruit Project Manager