Before you can begin to plant your fruit, nut or berry orchard, much planning has already occurred. Site selection, water management, enterprise budgets, research on pest and disease management practices, marketing plans, soil testing and site preparation are all on the list of must-dos before even considering which varieties to grow.
After you’ve worked through the initial preparation, selecting nursery stock becomes the priority. Along with selecting the cultivars – and in the case of some fruits, rootstock – best suited to your site’s individual characteristics, you have to find the best source of that stock. All nursery stock isn’t created equal, and the difference isn’t only in plant size, pricing and variety.
While selecting stock well-suited for your specific planting micro-climate is important, the nursery from which you purchase does not necessarily have to be local to you. Likewise, the size of the nursery does not indicate whether the quality or selection will be compromised.
“Region of production is not necessarily important. A good quality tree can be produced in every region, and so can a poor quality one,” James Luby, professor and plant breeder at the University of Minnesota, said. “Some small producers actually offer larger selections of varieties than larger producers.”
Nursery stock characteristics
But the nursery source does matter, for various reasons. Growing nursery stock requires a different focus than growing trees for fruit production. For an example of the production and cultivation practices seen in a nursery growing fruit crops for commercial orchards, Burchell Nursery, in California, offers this graphic timeline: http://www.burchellnursery.com/for-commercial-growers.php. The Burchell Nursery website also offers some insight into the development of their clean, virus-free seed stock:
“Decades of research and painstaking development resulted in the introduction of Burchell Nursery’s Healthy Start Trees in 2002 – the first ‘clean’ trees in the industry. This program was so successful that it was adopted by the California State Department of Food and Agriculture as the standard. Burchell seed is grown on its own hardy, virus-free Nemaguard (nematode resistant) rootstock, which is certified by the California State Department of Food and Agriculture through Stanislaus County. Each Healthy Start Tree is virus checked and virus free to help ensure that our customers have the best possible rootstock for their orchards.”
Virus-free stock is important not only in tree fruits but in strawberries and brambles, too. Tissue culture plant materials, sterilized soils, controlled environments to limit insect and diseases, and extensive testing of stock for viruses, is an industry best practice. Nourse Farms, in Massachusetts, known for supplying commercial growers with vigorous berry plants, describes its standards here: http://noursefarms.com/commercial-growers/plant-propagation/.
Details the nurseries provide to prospective growers allude to the nature of breeding and propagating nursery stock. Whether flowering plants, trees for landscapes, or fruit-producing crops, propagating perennial nursery crops is a complex undertaking.
“Source of the stock is very important due to a number of factors,” Luby said. There are many differences that will impact subsequent success in the orchard: “from a producer’s choice and quality of rootstock that they start with their use – or not – of virus testing and clean stock maintenance programs; nursery growing and harvesting practices; post-harvest handling and storage; and delivery.”
Cultivar, rootstock and growing needs
Plant breeding has resulted in myriad varieties of fruits of every type. The majority are available to growers who wish to give them a try, and are available from numerous nurseries of all sizes, across the nation. But there are some fruit cultivars not readily available. The new rise in “club” fruits, moves beyond mere patented varieties and royalties paid to breed programs. It also involves trademarks and management strategies for quality control as well as quantity and pricing control, which enable only a select, limited group of nursery growers to propagate these varieties, and a limited number of farmers permitted to grow them. To further complicate matters, there are also branding initiatives, where a publicly available cultivar is grown under a brand name by select producers.
When choosing from available nursery stock, select cultivars that fit well with your marketing outlets. Selling retail locally, shipping fruit to far-off buyers, selling to the processing market or to wholesale distributors, serving local restaurants, or opening your fields to pick-your-own enthusiasts can all require fruits with very different characteristics. Ripening times, appearance, flavor, fragility, storage needs and even yield can make one variety a better fit than another. And, the price received per unit can vary, too, both with variety and with marketing channel, and needs to be taken into consideration when making nursery stock purchases.
“Every grower should have a business plan, and the various needs to fit into that plan,” Luby said. “Economics of cost establishment versus how rapidly there is a return on the investment is the main trade-off for tree size. How quickly you want it to fruit (and) how much you want to spend (will determine the size of the nursery stock purchased). “Bigger trees typically get to full size and full fruiting potential more quickly, other things being equal.”
Fruit cultivars are typically propagated asexually, Luby said, and are therefore genetically identical – clones – of the parent plant. But mutations – also known as sports – do occur. Some of these go on to be commercially produced. Red Delicious, for example, is a sport of the Delicious apple. The Fuji apple has several commercially-grown sports. Honeycrisp – a cross between a Macoun and Honeygold – has generated a new sport, the popular Royal Red Honeycrisp. Growers should find out if the nursery is growing the primary variety or a sport, and what the differences in characteristics are, Luby advised.
Sexually propagated tree fruits are normally only used in breeding programs or to produce more seedling rootstock.
Cutting, budding and grafted are means of asexually propagating fruit cultivars, as is tissue culture. Stone fruit cultivars with good fruit characteristics are often lacking in root vigor. Cultivars with desired fruiting characteristics are paired with vigorous rootstocks, to offset their naturally poor root systems, and to allow for growers to select both the fruit varieties that work best for their needs, as well as the rootstock that works best in their growing conditions.
The cultivar selection of fruit, berry or nut needs to be made with due consideration given to your growing conditions. Sensitivity to frost, common disease resistance or susceptibility, size of the fruit, ripening time, flavor and other qualities of the fruit itself are usually primary reasons a producer opts to plant any given variety. But with some fruits, selecting the rootstock, which not only has its own characteristics but also can impact the fruiting cultivar’s traits, is just as important.
“In general, rootstocks should be chosen, which are best suited to a region,” Luby said. “A selection of different ones is useful as long as they are adapted in terms of such factors such as cold hardiness and disease resistance.”
But not all fruit cultivars are compatible with all rootstocks. Issues may not be seen for several years, however. Poor tree vigor, small fruit size, delayed leaf growth and delayed ripening are common issues. Selecting the proper rootstock – to which the desired cultivar is grafted or budded – is critical. Rootstocks can impact the timing of plant dormancy, resulting in dwarfing varieties, which may or may not be desirable.
“Rootstocks need to be matched to characteristics of the different scion varieties such as vigor differences, as well as soil and site differences that may affect vigor or prevalence of soil disease,” Luby said.
Rootstocks can be propagated from seed or asexually. Seedling rootstocks have great variability, not only for fruiting characteristics but also for root characteristics. Issues can arise with root structure, ability to tolerate environmental stress, and susceptibility to root-specific disease or pest pressures, too.
Clonally propagated rootstocks can sometimes be natural, in the case of species that have the ability to grow an embryo solely from the mother plant, with no male fertilization required. Some apple species, as well as citrus and mango, have this ability. Otherwise, clonal propagation of rootstocks, which prevents the variability seen in seedling rootstocks, requires human intervention.
Nursery stock growers have years of breeding experience, tried-and-true methods of propagation, and newer, more precise methods, such as micropropagation, done in vitro with small amount of tissue. Some of these procedures are proprietary, unique to the nursery grower. With such a variety of options, crop selection is much more complex than choosing a variety and ordering from a catalog.
Whether planting a new orchard or adding new plants to existing orchards, selecting varieties that not only meet the needs of your customers but the needs of your fields, is vitally important. Asking questions of the nursery grower, to learn how their breeding, propagation, harvesting and handling techniques may impact the success of your orchard for better or for worse is a necessity. Combining this information with pricing considerations, as well as rootstock and cultivar suitability to your needs and growing conditions, can make the difference between a thriving orchard, and a bad experience.
For information on James Luby’s research: http://experts.umn.edu/en/persons/james-j-luby%281becd242-2d6f-49e0-a171-2b5cdb31fc6f%29.html
For further information on nursery stock propagation: http://fruitandnuteducation.ucdavis.edu/education/fruitnutproduction/Stone_Fruit_Propagation/grafting/