Fresh blueberries

If you’re looking for a shrub that serves double (maybe triple!) duty, why not consider blueberries? Native to the U.S., blueberries offer not only delicious, health-giving fruit from mid-summer to early autumn–but also delicate white or pink flowers in spring, glossy, dark green foliage during summer, and gorgeous fall colors in oranges, reds, and yellows. What more could you ask from a plant!

Blueberry round-up

Iowa growers can choose between three varieties. Highbush blueberries grow from 5-9’ and offer good disease resistance. They also take up a lot of space. Half-high varieties have greater cold hardiness, grow around 3-4’, produce the same excellent fruit as their larger cousins, and are probably the most practical for home gardeners because their smaller size permits more bushes in the same amount of space—and, thus, greater fruit production. Half-high berries are a cross between highbush and lowbush varieties.

Lowbush, or wild blueberries, some of which can survive to zone 2, usually top out around 18”. They’re suitable for containers or for in-ground planting. Some growers use them as a “fruitful” ground cover. If you opt for containers, choose large pots with drainage holes, fill them with acid soil mix, and place them in a sunny site. Protect them in winter by moving the pot to a sheltered location, burying to the pot rim, or covering with a thick wall of straw or wrapped in burlap or rose wrap. The idea is to protect the roots and the canes.

Blueberry needs

Blueberries require specific conditions. First is full sun. They’ll grow in part shade but will not prosper, so why not give them what they want in the first place—lots of sunshine!

Second, an acid soil of between 4.0 and 5.5 pH. Most of Iowa’s soils are alkaline, so you’ll need to acidify with a 50-50 mix of native soil and acid peat moss–dampened a bit first. Add a small amount of soil sulfur—available at garden stores or online—enough to raise the pH.  Do not be tempted to hurry the process with aluminum sulfate because it can burn the shallow roots. Prepare soil the previous year. If in doubt, have your soil tested.

Third, provide moist but well-drained conditions. Blueberries will rot in constantly wet soil and languish in dry or heavy soil. They like sandy, peaty soil (not all-peat!). Ensure a cool root-run with adequate mulch, as blueberry roots are very close to the surface.

You can purchase blueberries bare-root or in containers. Either way, plant in spring—and nowhere close to a black walnut tree. Dig a wide, shallow hole and amend the soil then set them in. Water well and apply several inches of loose mulch.

To ensure good fruiting, plant two or more cultivars. The first two years, pick the blossoms off in order to channel all the plant’s energy into developing a strong root system. By doing this, you are preparing for the long haul; if blueberries are given the right conditions, they can live many years (as long as a century, according to one source) and increase in beauty and fruit production each year.

In spring of the second year, fertilize with any azalea or acid-plant fertilizer, e.g. Holly Tone or similar. Avoid depending on liquid “one-application” fertilizers. Provide a loose mulch of about four inches.

Critter and winter protection

Unless you want to feed neighborhood birds, cover the bushes with netting once berries start to ripen or the birds will most definitely get the entire crop. You can find the right netting—half-inch or one-inch—at garden centers or online.

If deer and rabbits are a problem in your area, you’ll need to provide winter fencing or the buds will be stripped from the branches and you’ll have no berries that year. Chicken wire may be too flimsy to deter the deer.

As for winter protection, not much is needed. Blueberries suitable for Iowa are extremely hardy. However, since blueberry roots are shallow, 2-4” of mulch (straw, pine needles, shredded leaves, shredded bark, etc.) applied after the ground freezes will do the trick. To avoid disease and/or creating a home for mice, keep the mulch away from the base of the canes.

Specific varieties

You have your choice of varieties, no matter which kind of bush suits your needs.

• Highbush: Duke, Patriot, Bluejay, Blueray, Bluecrop, Rubel, and Elliot.
• Half-High: Polaris, Northblue, Northsky, Northcountry, St. Cloud
• Low-bush: Brunswick, Burgundy, Little Crisp, Ruby Carpet (Also look for so-called patio varieties.)

Pruning blueberry bushes

Continue disbudding the first two years. Expect a decent crop after four years. After several seasons, you’ll need to prune out some of the old wood every year to make room for new canes–or fruiting will diminish. Late February or early March is the ideal time.

Old wood is easy to identify. It’s light gray or light brown, brittle, and has shaggy bark. Cut a few of those to the ground. (Avoid leaving stubs.) This allows space for young canes to form. Young canes are smooth and supple-looking with plump, red buds at the end. (Never shear bushes unless you’re growing them purely for ornament—because shearing will remove fruiting buds.) After pruning, your bush should have between 10 and 15 canes, a mixture of old and (mostly) new wood. The center of the bush should be open to sunlight.

Try a few!

Blueberries are like any plant—and like people—in the right conditions they’ll flourish. Given the right soil and pH, the right moisture, proper pruning and good sunlight—blueberries will repay you in beautiful blossoms, delicious fruit, and gorgeous fall color for a long time. In fact, they might last longer than you! Start preparing the soil now!