How to prune blueberry bushes for maximum growth
When you prune blueberry bushes, you affect not only the shape of the plant, but also how much fruit the bush will produce, the size of the fruit, and when the fruit will ripen. That’s plenty of incentive to prune them correctly. Here’s how.
How to prune — The key to pruning blueberries is to remember that fruit is borne on 1-year old wood. Pruning done in early 2014 causes new growth that summer on which the 2015 crop will form. Pruning 1-year old wood in 2014 removes potential fruiting sites for that year.
New wood can be canes that grow from the base of the plant or new side shoots from existing canes. To force new canes to grow, remove one out of every four or five old canes (those that are bigger in diameter and have a weathered look) at the ground. Preferentially take out canes in the center of the plant to allow more air and sun inside.
Remove older side shoots that have already borne a crop. Cut off branches growing near the ground at the point where the branch meets the stem. Vigorous young canes can get quite tall. Cut these back to 6 inches or so below the desired bush height to force new lateral branches to form.
When to prune — Blueberry bushes should be pruned in late winter or early spring before new growth appears. Diseased or damaged wood can be removed at any time.
How much to prune — Pruning reduces the number of fruit buds. The plant puts its energy into the remaining buds, resulting in larger fruit. For homeowners, moderate annual pruning will generally result in acceptable fruit size.
Light to moderate annual pruning is recommended for homeowners who want an extended fruiting season. Heavy pruning tends to make the fruit ripen earlier and over a shorter period, something commercial growers like.
Until you have some experience with your cultivars, err on the side of pruning too little. As plants age and develop a larger root system, reduce how much you prune each year. This will balance the fruit load with the roots’ capacity.
Pruning young plants — Trim off all blooms for the first two years. I know this is tough to do, but this allows the plant to put its energy into root growth instead of fruit production. Prune aggressively at the beginning of the second year to stimulate new growth for blooms (and your first crop) in year three.
Pruning older bushes for renewal — When production starts to decline after eight or 10 years, remove all weak canes and prune heavily for a year or two to stimulate new growth. The crop will be smaller for a while, but the plant’s health should be renewed.
For more information, download the Horticultural Information Leaflet “Principles of Pruning the Highbush Blueberry,” at http://www.ces.ncsu.edu/depts/hort/hil/pdf/hil-201-b.pdf.
Don’t forget that blueberries like acidic soil (pH 4.0 to 5.0). Get the soil tested to see what you need to do to keep it in this range. And plan on netting or another barrier to keep the birds from stealing your crop.
If you’d like to plant blueberries this year, the Haywood County Master Gardener Volunteer Association plant sale has them (and many other plants) at extremely reasonable prices. Call the Haywood County Extension Center at 456-3575 for an order form; place your order by March 14 for pick-up on Saturday, April 12. Or email firstname.lastname@example.org and we’ll reply with an order form you can print out.
Jim Janke is an Extension Master Gardener Volunteer in Haywood County. For more information call the Haywood County Extension Center at 828-456-3575. © 2014 NC State University.