Pruning of 'Natchez' Blackberry
A thread I have been participating on with the North American Raspberry and Blackberry Association (NARBA) email discussion group regards the heavy fruiting of the blackberry variety 'Natchez' and the subsequent repercussions on fruit ripening and to some extent flavor. This is a fairly common problem here on the Central Coast with growers of this variety and I have been asked on several occasions what to do about it.
As one can see from the picture below, the ability of 'Natchez' to produce fruit is tremendous, but unfortunately the leaf area to fruit ratio is rather low here, resulting in the ripening problems mentioned above.
This past week we were fortunate enough to have plant breeder John Clark, who among other blackberry varieties bred 'Natchez', weigh in on managing overcropping of this variety.
He writes that 'Natchez' plants without any lateral shortening, ie pruning of the laterals, overcrop (load up with too much fruit), especially on plants which are fruiting in the first year after planting. He suggests that laterals be shortened to 15-25 inches long (prior to flowering obviously) to limit the crop down to what the plant can ripen with the available leaf surface area and carbohydrate reserves in the plant itself.
Simply put, the key to getting 'Natchez' to ripen and flavor up properly is maintaining an adequate ratio of leaves to fruit by pruning the laterals back to 15-25 inches.