There are two main commercial types of plums: the European plum (Prunus domestica) and the Japanese plum (Prunus salicina), each having many varieties. The European varieties are mainly grown for processing into dried plums (also known as prunes), but are also grown for the fresh market. Japanese varieties are almost always grown strictly for the fresh market (University of California, 2015) (Michigan Plums, 2012). Early settlers introduced the European plum to the United States, whereas Japanese plums were first brought to California in 1870 (Sunwest Fruit Company, 2014).
The marketing season for California plums is May 15 to Oct. 20t; for California prunes it is Aug. 20t to April 15t. The marketing season for plums and prunes for fresh use and canning from Idaho, Michigan, Oregon and Washington is from Aug. 15 to Oct. 15 (NASS, 2015).
Schools have been focusing on healthier options for their students, and thus they are buying more locally sourced food. Dried plums are a great option for foodservice operators to introduce into their schools. They can be pitted and eaten whole, or used to improve processed foods. Plum puree is a great substitute sweetener for reduced fat baked goods, and works great to improve flavor and retain moisture in pre-cooked meats. Food service operators and farmers can both benefit from this exchange by working through a government program called Farm to School (CDPB, 2015) (USDA, 2015).
Other means of adding value to fresh and dried plums could be selling them through farm stands, farmers’ markets, U-pick operations, and Community Supported Agriculture (CSA). CSAs truly allow the community to be involved in the farming experience. Members of the community buy a subscription in advance from the farmer to receive a share of the farm’s crop throughout the growing season. CSAs are unique because the members also share in the risks farmers face, such as poor harvests due to adverse weather or pests. Selling to the community in advance provides the farmer with the working capital needed to run the farm, gets the farmer better prices for their crop, and eliminates time and money otherwise spent on marketing avenues (NAL, 2014).
In 2014 California produced 126,000 tons of fresh plums from 18,000 acres. The total value of the crop was $115.8 million. California also produced 285,000 tons of prunes (dried plums) from 48,000 acres. The total value of the crop was $209 million.
Four other states also produce fresh and dried plums commercially. They are Oregon, Idaho, Washington, and Michigan, in order from largest producer to smallest. Together, these states harvested 14,700 tons of plums from 2,500 acres. The total value of the crop was $7.4 million.
The value of utilized production for plums and prunes for 2014 has increased from 2013. California plums increased 87 percent. California prunes increased by 23 percent, and prunes and plums from Idaho, Michigan, Oregon and Washington have increased by 20 percent (NASS, 2015).
In 2013, Japan was the largest market of exported dried plums at 26.2 million pounds, with a value of $32.4 million. Germany followed closely, receiving 24.7 million pounds of dried plums with a value of $35.1 million. Canada was the largest market for exported fresh plums at 40.2 million pounds, with a value of $27.7 million (ERS, 2015).
Chile provides nearly all of the imported plums to the United States, accounting for 80 percent of the total. In 2014, the United States imported 12 million pounds of dried plums and 66.7 million pounds of fresh plums from Chile. The majority of plum imports enter the United States between January and May, during the off-season for U.S. plum production (ERS, 2015).
A characteristic of many stone fruits is alternate bearing (AB), meaning the plant will produce more fruit every other year. AB is internally regulated by the plant, but can be triggered by external factors such as poor management. The most successful practice to control AB is crop load management achieved by fruit thinning and pruning (Pennsylvania State University – Extension, 2011). Most fruit trees, including plum, also require chilling hours (close to freezing temperatures) to induce flowering. Generally, European plums require 700-1,000 chilling hours and Japanese plums require 500-900 chilling hours (UC IPM, 2014).