Mullberries

By Gina Marzolo, graduate student of agricultural sciences, California State Polytechnic University, Pomona, grmarzolo@cpp.edu, August 2016.

Edited by Dan Lee, communications specialist – College of Agriculture, California State Polytechnic University, Pomona, August 2016.

Introduction

Mulberries are the fruit from mulberry trees, which are in the Moraceae family. The three most common commercial mulberry species include white mulberry (Morus alba), black mulberry (Morus nigra), and red mulberry (Morus rubra) all having multiple cultivars (“Mulberry” – CRFG, 1997) (“Mulberry” – UnCommon Fruit, 2013).  

White mulberry is native to eastern and central China; red mulberry is native to areas of the central and eastern United States; and black mulberry is native to western Asia (“Mulberry” – CRFG, 1997).

Mulberry fruits range in size and length, but most resemble the size of a blackberry. Depending on the variety and ripeness, mulberries can exhibit an extremely sweet flavor to a tangy sweet flavor (McNatt, 2014). Fruits from black mulberry are said to have the best flavor with an equal blend of sweet and tart. The name of the mulberry species does not necessarily reflect the color of the fruit: for example, fruit from white mulberry can be white, lavender or black, while fruit from red mulberry can be a deep red color to almost black (“Mulberry” – CRFG, 1997)

Marketing Channels

Depending on the species, mulberries in the United States ripen during the spring or summer season. White and red mulberries are usually ready for harvest by late spring, whereas black mulberries do not ripen until mid to late summer (“Mulberry” – CRFG, 1997).

Mulberries are a very delicate fruit. For this reason, they have been lacking as a commercial commodity. However, U.S. demand for fresh mulberries is increasing, especially by high-end restaurant chefs in California, and the price received for mulberries can be as high as $10 to $15 per pound (Singhal et al, 2010) (Avakian and Martin, 2016). Fresh mulberries are best sold locally through farm stands, farmers’ markets, specialty grocery stores and/or restaurants.

Mulberries are a familiar fruit for many people from the Middle East, Central Asia, the Caucasus and the Far East, thus possibly a niche market for the crop (Bahrampour, 2010) (“What is Niche Marketing?” – Penn State Extension, n.d.).

Another marketing opportunity with mulberries could be advertising their nutritive benefits. Dark-hued mulberries are rich in anthocyanins. Anthocyanin pigment is common in a variety of fruits and vegetables that contain a red, purple or blue color such as blueberries, blackberries, red cabbage and eggplant (Butelli, et al, 2012). Research has shown that anthocyanins have many health benefits, such as anti-inflammatory and anti-carcinogenic properties, and properties that can aid in lowering diabetes risk (Pojer, et al, 2013).

Selling an intriguing variety such as Pakistan mulberry (Morus macroura var. Pakistan) can also pique customers’ interest. Pakistan mulberries are longer than most mulberries, and their skin is firmer, thus easier to transport and package. They exhibit a deep red to almost black color and have a tremendously rich sweet flavor (Karp, 2010).

Mulberries can also be dried, frozen, or processed to add value. Mulberries have been processed into products such as baked goods (cakes, cookies, pies, etc.), jams, juice, paste and pulps, syrup, and wine (Singhal et al, 2010).

Production

Generally, mulberry orchards have been in production not for their fruit, but for their foliage (Singhal et al, 2010). In nature, certain insects are host specific, meaning that they only feed on a specific type of plant. This is the case with silkworms (Machii, 2002). Rearing silkworms has been a practice for millenniums and is called sericulture. The current top countries growing mulberry trees for sericulture are China, followed by India and Japan (Singhal et al, 2010). White mulberry trees were initially introduced into the United States for sericulture, but that commercial venture did not pan out (Wyss, 2010).

Mulberry leaves are also favorably palatable and easy to digest by herbivorous animals, thus many countries (especially Latin American countries) use the leaves as the main forage for goats, sheep, and rabbits as well as a supplement in forage for cows (Sánchez, 2002).

The commercial production of mulberry trees for their fruit has only been considered within the last two decades (Singhal et al, 2010) (Machii et al, 2002). Mulberry trees take approximately 10 years to produce fruit from the seedling stage; however, propagated or grafted varieties could produce fruit sooner (Doxon, n.d.).

Exports/Imports/United States Consumption

The United States Department of Agriculture’s Economic Research Service reports the exports imports and per capita consumption of many commodities. However, since mulberry is an emerging fruit crop in the United States, only import data of frozen mulberries is currently available (“Fruit and Tree” – ERS, 2013).

For the 2015 market year, the United States imported almost 3.4 million pounds of frozen mulberries valued at $2.6 million. The two main countries providing frozen mulberries were China closely followed by Chile (“Fruit and Tree” – ERS, 2013).

There is currently no United States export or import data available on mulberries reported through the United States Department of Agriculture’s Foreign Agricultural Service (FAS, 2016).

Management

Mulberry trees can be monoecious (male and female flowers on the same tree) or dioecious (all male or all female flowers on separate trees). However, it must be cautioned that stress can cause a mulberry tree to switch sex. Therefore, purchasing dioecious mulberry trees is a safer bet for fruit production, as they also do not require cross-pollination for fruit set (Doxon, n.d.) (“Mulberry” – CRFG, 1997).

White and red mulberry species grow in a natural tree form, although pruning can increase fruit production. Black mulberry tends to grow in a shrub form and thus needs to be trained as a tree (Doxon, n.d.).

Mulberry trees are very drought tolerant; however, irrigation is recommended to prevent premature fruit drop, especially during drier seasons (“Mulberry” – CRFG, 1997).

Currently, the most common method of harvesting mulberry is by physically shaking the branches to release the fruit (Singhal et al, 2010). There is the potential of mechanical harvesting by using machines that shake the tree, similar to those used in harvesting tart cherries for processing (“Mulberry” – UnCommon Fruit, 2013).   

Mulberries can be grown in many different areas of the United States. One of the major considerations when starting any fruit tree orchard are the plants required chill hours and frost concerns. Mulberries require approximately 400 chill hours to induce flowering (number of hours between 32 to45 degrees Fahrenheit) (Jones and Costello, 2007). White mulberry and red mulberry species can both tolerate subzero temperatures, with white mulberry being able to withstand temperatures as low as -25 degrees Fahrenheit. Black mulberry is the least cold tolerant of the three species and will be damaged below subzero temperatures (“Mulberry” – CRFG, 1997).

Financial

There are currently no mulberry enterprise budgets available due to mulberry being a minor fruit crop.

Sources

Avakian, T. and Martin, E. (2016). What it’s like to eat at the best restaurant in California, where a meal will cost you $310 a person, Business Insider – Finance.

Bahrampour, T. (2010). In Washington, mulberry trees offer many immigrants a taste of home, The Washington Post.

Butelli, E., Licciardello, C., Zhang, Y., Liu, J., Mackay, S., Bailey, P., Reforgiato-Recupero, G., and Martin, C. (2012). Retrotransposons Control Fruit-Specific, Cold-Dependent Accumulation of Anthocyanins in Blood Oranges, Plant Cell, 24: 1242-1255.

Doxon, L. (n.d.). Mulberry pruning and the bearing of fruit, SFGate.

Foreign Agricultural Service (FAS) – Global Agricultural Trade System (GATS), USDA, 2016.

Fruit and Tree Nut Data USDA Economic Research Service (ERS), 2013.

Karp, D. (2010). Market Watch: Deliciously strange Pakistan mulberries, Los Angeles Times.

Jones, K.S., and Costello, L.R. (2007). Selecting fruit, nut and berry crops for home gardens in San Mateo and San Francisco counties, University of California Division of Agriculture and Natural Resources.

Machii, H., Koyama, A., and Yamanouchi, H. (2002). Mulberry breeding, cultivation and utilization in Japan, Animal Production and Health Division, Food and Agriculture Organization of the United Nations.

McNatt, C. (2014). Mulberries sweet, but beware trees’ dark side, The Orange County Register.

Mulberry, California Rare Fruit Growers (CRFG), 1997.

Mulberry, University of California Integrated Pest Management Program, 2016.

Mulberry, UnCommon Fruit, 2013.

Pojer, E., Mattivi, F., Johnson, D., and Stockley, C.S. (2013). The Case for Anthocyanin Consumption to Promote Human Health: A Review, Comprehensive Reviews in Food Science and Food Safety, 12: 483-508.

Sánchez, M.D. (2002). Mulberry: an exceptional forage available almost worldwide!, Animal Production and Health Division, Food and Agriculture Organization of the United Nations.

Singhal, B.K., Khan, M.A., Dhar, A., Baqaul, F.M., and Bindroo, B.B. (2010). Approaches to industrial exploitation of mulberry (Mulberry sp.) fruits, Journal of Fruit and Ornamental Plant Research 18(1): 83-99.

What is niche marketing?, Penn State Extension, 2016.

Wyss, B. (2010). Connecticut’s Mulberry Craze, Connecticut Explored 8(3).

Links checked August 2016.