Organic Broadcaster

Choose hardy cultivars for best bramble berries

By Paul M. Otten

Autumn Britten starts producing around the middle of August in east-central Minnesota, and tends to be somewhat more productive than other cultivars, with slightly larger and more elongated berries and taller canes.

Autumn Britten starts producing around the middle of August in east-central Minnesota, and tends to be somewhat more productive than other cultivars, with slightly larger and more elongated berries and taller canes.

Bramble berries—raspberries and blackber¬ries—can be great additions to the diversified market farm or orchard. They are a favorite at farmers markets, in CSA boxes, and at pick-your-own operations. They are a perennial crop that will produce for many seasons if cared for properly. Successful bramble production depends on several factors, including soil and cultivar selection.

As organic growers, we know we must build and steward the soil to grow nutrient-dense, health-sustaining, disease- and insect-free crops. Healthy soil is especially important for growing bramble berries since half of each plant resides in the soil. What we see above ground is nearly a 100% reflection of what transpires below ground, in the soil environment. We can only do so much about the above-ground environment— temperatures, rain, winds, etc.—but we can do a lot about the environment in which half of our plants live.

Insects and diseases are not the primary cause of problems in berry production. Of greater importance is the environment in which the plants are grown, and no part of the environ¬ment is more important than the soil.

Brambles are adaptable and can be made to thrive in most soils. However, it will help us make the wisest site choices if we keep in mind the most basic biological needs of plants. The number one need by far is air. Neither you nor I nor bramble plants can function when this basic need is restricted.

The most expensive machine I have on my farm is a large Imants spader that aerates the soil 17” down. It is our primary soil-building tool. Long before I think about other nutrients, I think about air. No amount of NPK or other elements can make up for the lack of air—the most important plant nutrient of all. Faithfully using green manure crops, especially those with massive root systems such as Sudan grass and winter rye, goes a long way in rapidly raising organic matter and thus bring¬ing air to the roots, even after massive rains. (Don’t expect to read about air management because it can’t be pat-ented, bagged or easily sold!)

Practically all pathogenic soil organ¬isms (animal and human) thrive in an anaerobic environment and are naturally suppressed in an aerobic one. That’s true even of cancerous cells. By building aerobic soils, we not only favor our bramble plants, but also eliminate the environment that fosters root dis¬eases—killing two birds with one stone. To top it all off, we also support the soil biology that in turn feeds out plants. Thinking ever more WHOLE-istically will lead us to craft our soils to enable them to produce healthy plants and a healthy return on our investment.

Minerals play a vital role in a plant’s susceptibility or resistance to diseases. The American Phytopathological Society recently published an awe¬some 280-page book entitled, Mineral Nutrition and Plant Disease, authored by scientists from around the globe. Though academic by its very nature, this book provides great insights into plant nutrition, disease, and health. The bot¬tom line from this book is that practically all diseases in plants, animals and mankind are caused or facilitated by mineral deficiencies or imbalances. This illustrates why the most important thing growers can do for the health and quality of their crops is to build, care for and steward their soil.

Cultivar Selection

When selecting plant cultivars (cultivated vari¬eties) for your farm, there are several important aspects to evaluate. The Upper Midwest is one of the harshest environments in which to grow tender fruit like raspberries and blackberries successfully. We can have extremely cold win¬ters—sometimes with a lot of snow, sometimes with hardly any. We can have ferocious winds. We have floods and droughts. We have extreme mid-continent heat in the summer. And, we have drastic fluctuations in all of these to the point where Minnesotans are heard telling their guests, “If you don’t like the weather, just wait a minute!”

Let’s make one thing clear at the outset: there are no perfect cultivars for anywhere, much less for the Upper Midwest. Each choice involves a series of compromises. Finding the most suited cultivar for each area is best done by a process of elimination. My suggestion is for growers to become familiar with various cultivars by trying 10-20 plants, then deciding which best suits their needs and performs best in their area and soil. The issue of winter hardiness trumps all the others. If plants don’t consistently survive to produce a marketable crop, there is little sense in growing them.

With raspberries and blackberries, winter hardiness concerns only summer-bearing cultivars because their canes grow up one year, must overwinter well and produce their crop the subsequent season. With the fall-bearing type, we don’t care about cane cold-hardiness. Nearby fellow-growers and extension service can be valuable resources to help choose proven culti¬vars. For central Minnesota and similar areas the list of cultivars is quite limited. I share my experience with these on page 14.

Factors to Consider

Choose cultivars that will provide berries that match your intended uses. Ask yourself: Why am I planting my berries? What use am I planning for them? Do I intend to process them into wine, jam, jelly, juice, syrup, toppings, chutney, ice cream? Do I plan to sell them retail, pick-your-own, wholesale or freeze them for local processors? Do I want a summer or fall crop? Finally, what colors of berries am I looking for and why?

Also consider when you want to harvest berries. You have two choices: a summer crop, lasting approximately 3 weeks—the first 3 weeks in July in the Upper Midwest—and a fall crop, typically lasting 5-6 weeks—mid-August until the end of September. There is a much greater maturity span with fall-bearing cultivars than there is with summer ones. During the sum­mer, these tender berries need to be picked at least every second day. The cooler fall tempera­tures give growers a bit more picking flexibility. However, with the advent of the SWD (Spotted Wing Drosophila) every effort should be made to pick ALL berries as soon as they are ripe.

Disease Resistance

When you have a choice, select cultivars that have genetic strengths against the major raspberry diseases. With the limited choices for the Upper Midwest, this is less of an issue than if we grew brambles in California or the Pacific Northwest. We have reasonably good genetics in the varieties listed below—especially the newer ones. Summer-bearing varieties will show their weaknesses more readily, possibly because the canes are around for two seasons. For example, Killarney is beginning to manifest some serious foliar weaknesses under certain summer conditions. With fall-bearing cultivars, the canes and foliage are around only for one season, so they all tend to remain quite healthy.

Fungal diseases can be largely controlled by cultural practices: soil stewardship, plant density, air circulation, proper pruning and trellising, and even harvesting. Viral diseases are best dealt with by securing clean stock, genetic resistance and eradicating nearby native brambles. All growers should apply regu­lar nutrient and compost tea sprays throughout the season. The healthier the plant, the more resistant it will be especially against fungal and bacterial diseases.

Suggested Cultivars

Raspberries: Summer Bearing (Floricane)

The canes of these plants grow up one season, overwinter, produce a crop the second season, then die and need to be pruned out.

Red: Nova, Encore, Prelude, Killarney, Latham

Black: MacBlack, Jewel, Bristol

Purple: Royalty, Brandywine

Raspberries: Fall-Bearing (Primocane)

Commercially, these plants are chopped or cut down to the ground in late winter or very early spring (before they break dormancy) to “force” the plant to grow new canes that produce their crop during the first fall.

Red: Autumn Britten, Caroline, Joan J, Jaclyn, Heritage, Autumn Bliss

Gold: Anne

Black: coming soon (from Peter Tallman, Colo.)

Blackberries: Summer-Bearing (Floricane)

The canes of these plants grow up one season, overwinter, produce a crop the second season, then die and need to be pruned out. Generally we don’t think about growing blackberries in Minnesota or Wisconsin because the bearing canes of even the most cold-hardy ones don’t survive above the snow line.

Doyle – There has been some success with this extremely vigorous, thornless cultivar in the southern half of zone 4.

Illini Hardy is an erect and thorny variety. This is likely the most cold hardy cultivar, and can be grown in zones 5 and warmer.

Chester, a widely grown thornless cultivar, is superior to Illini Hardy in a variety of ways, but a little less cold hardy. Best for zone 5 and warmer.

Find your zone.

Blackberries: Fall-Bearing (Primocane)

Prime Jim & Prime Jan: Both cultivars are extremely spiny and too late to produce a crop in zone 4, but worthy of trial for zone 5, which has a longer growing season.

My Cultivar Choices

Raspberry, Summer, Red

For us at Natura Farms, located in the north­east fringes of the Minneapolis-St. Paul metro area in zone 4b (-25 to -20º F), our most consis­tent performer has been Nova. It has a round, bright red, firm fruit, with coherent small drupelets that pick easily and hold up well after harvest. The canes are sturdy, vigorous, and nearly spineless, the fruit is tasty, and the plant is resistant to most cane and foliar diseases. It can be grown also in zone 3.

Next come varieties like Killarney (but very spiny and some foliar disease susceptibility); Latham (a 100-year old Minnesota heirloom, mildly spined, good tasting cultivar, and can be grown in zone 3); Prelude (the earliest to ripen, with very good flavor, that also bears a small fall crop); Encore (the latest to ripen, nearly spineless, good flavored, with coherent, large berries) and Lauren (not quite winter hardy enough for us, but we like its long season and good flavored, large fruit).

Raspberry, Summer, Black (Very spiny)

Mac Black is the latest ripening and all around best performer for us. Jewel is mid-season with very large berries. Bristol is the earliest ripen­ing, an heirloom, with very good flavor, but is only marginally hardy for us.

Raspberry, Summer, Purple (Quite spiny)

Brandywine is unsurpassed for jam, jelly, syrup, toppings and pies because of its intense flavor and tartness. Royalty is for those who love the taste of purple raspberries (the result of crossing blacks with reds), but want a sweeter berry. It is very productive and can be picked in the red (almost ripe) or purple (ripe) stage.

Raspberry, Fall, Red

Autumn Britten has replaced Autumn Bliss for us and is still our #1 choice for its earliness, quality and yield, but there are a growing number of contenders, each having its specific attractions. Joan J and Jaclyn are two other great early varies. Caroline is a superb, produc­tive, mid-season cultivar with very vigorous plants and berries of intense flavor. Heritage is the good flavored, firm, medium-sized, mid-late season workhorse that brought fall-bearing raspberries to the world scene in 1969. Before then there were no commercial fall raspberries. When the early fall cultivars start winding down, Heritage kicks in and carries us through until the short days and frost end the season.

Raspberry, Fall, Yellow

Anne is for us the only yellow raspberry to grow. It is mid-season, highly productive, has sturdy canes, and is large-fruited, with excel­lent sweet flavor.

My suggestion is for growers to become familiar with all of them, by trying 10-25 plants, then deciding which best suits their needs and performs best in their area and soil.

For a chart of Berry Varieties at a Glance, see page 15 of the 2014 Nourse berry catalog. (www.noursefarms.com, info@noursefarms. com, 413-665-2658)

Paul Otten (pmo@chof.net) has worked with berries for 60 years on three continents. He consults, lectures and writes on berries and health. Paul has been a presenter at the MOSES Conference and many other national and international conferences. He has written for Rodale Press, Houghton Mifflin, Brooklyn Botanic Garden, Fine Gardening, and other publica­tions. He manages Natura Farms and his own berry nursery in Marine on St. Croix, Minn. 

March | April 2014