Aronia: A Old Fruit Crop, New for Maryland, Andrew Ristvey

A new alternative crop is being studied by University of Maryland Extension for organic fruit production. The black chokeberry, or Aronia to which it is commonly
referred, is an eastern U.S native with a long history of fruit production in Eastern Europe. The Aronia fruit is about the size of a large blueberry and comes in clusters
of about 10 to 20, making them relatively easy to pick. A mature plant (about 7 to 8 years) can yield over 15 lbs, but they start fruiting (averaging 3 or 4 lbs of fruit per
plant) within two growing seasons after planting. Interestingly, the fruit itself is more closely related to an apple than a berry and is dark purple in color. The color
is attributed to high concentrations of fl avonoids including anthocyanins and proanthocyanidins. Due to health-promoting effects, there is great interest in fruits and vegetables containing high concentrations of fl avonoids, which are considered potent
antioxidants. Recent studies have shown that Aronia has a very high Oxygen Radical Absorbance Capacity (ORAC) compared to other foods, including blueberries. The fruit has potentially strong benefi cial properties for health with regards to the function of coronary arteries, and still other studies suggest antimicrobial properties for urinary tract health, colon cancer-fi ghting properties and possibly aiding in the management of diabetes.
These qualities considered nutraceutical, heightens the marketability and sales potential of Aronia as a value added product for Maryland farmers. Several food products can be made from the fruit including juice, juice extracts, jelly, and wine. It is true that some processing of the fruit is necessary of overcome some of the fruit’s bitter qualities which stem from the fl avonoid content. At the Wye Research and Education Center an orchard has been maintained and studied for over 5 years.

Several interesting conclusions have been drawn.
• Aronia can be grown organically because there is little pest pressure
• Plants yield within the second seasonat densities similar to blueberries
• Plants tolerate a variety of soil conditions
• Can be easily propagated from cuttings or seed
• Plants are apomictic, meaning they self-pollinate.
• Planted densities are similar to blueberry.

Nitrogen fertility studies have shown that fruit yield is not infl uenced by high rates (above ¼ oz per plant) for the fi rst 5 years. Soluble sugar content is also unaffected by nitrogen rates at least initially. Ongoing research will determine if fruit yield can be maintained with rates at ¼ oz. nitrogen per plant or below.  Pest pressure is relatively low. At this time, only one fungus, Gymnosporangium sp (e.g. Cedar-Apple Rust) is suspected to affect the plants, although signs of the plant that show infection, including fruit, are minimal and fruit that are infected are usually aborted. More observations will be made in the following years. Insect pressure is also minimal, but includes aphids, lace bugs, Japanese beetles, and grasshoppers. The latter two are of most concern as they usually strip the leaf canopy, resulting in limited sugar production for the fruit. The past several years Japanese beetle pressure has been limited. This year grasshoppers seemed to have affected most of the leaf canopy and possibly sugar production. Apart from these few problems Aronia is an easy plant to grow and should be considered as an alternative fruit crop for anyone with at least a ½ acre.

ARONIA RESEARCH

Aronia Research

At Wye Research and Education Center an active orchard has been maintained and studied for over 5 years.  During that time, several interesting conclusions have been drawn.

• Aronia can be grown organically because of few pest species
• Plants yield within the second year after planting
• Can be grown at densities similar to blueberries
• Plants tolerate a variety of soil conditions
• Can be easily propagated from cuttings or seed
• Plants are apomictic, meaning they self pollinate.

Results from Fertility Research

Plants were established in May of 2006. They were planted in nursery fabric at a spacing of 3 feet on center with 9 feet between the 4 rows.  Plants were initially given 6 grams of N with a 5-3-4 organic fertilizer (McGeary’s Organic).   Rows were treated as blocks.  Half the rows continued to be fertilized with 6 grams of nitrogen the fall of 2006 and 2007 and then the spring of 2008.  The other blocks were fertilized with 3 grams of nitrogen during the same periods after the initial planting and fertilization.  Yields for the 2008 harvest showed that plants receiving 3 grams of nitrogen had an average yield of 2.8 kg (6.2 lb) per plant, while plants that were fertilized with 6 grams of nitrogen had an average yield of 2.2 kg (4.8 lb) per plant.

In 2009, split block nitrogen fertility trials tested 0, 3,7 and 14 grams of nitrogen per plant (Bartlett’s Natural).  Both yield and brix were tested at the end of the season after harvest.  Results showed that there was no difference in yield and brix between treatments. See Figures 1 and 2.

In 2010, the same treatments were applied and yield and brix measurements were taken again at the end of the season after harvest.  As in 2009 there were no differences in yield or brix between treatments.  See Figures 3 and 4. It seems as if the 14 gram nitrogen treatment averaged greater yield but with the variability in yield within treatments, differences could not be identified.

Even though yield seemed not to be affected by nitrogen rate, fertilizing is recommended in Maryland soils, especially during the establishment period with 7 grams or 1/4 ounce of nitrogen per plant.

ARONIA JUICE

Fresh Aronia juice can be easily made from the fruit after harvest. If prepared properly, the juice has little to none of the astringency of the fruit.  It is advisable to freeze the fruit for a couple days so that the pulp and tissues will express more liquid.  Since the pulp contains the compounds that make the fruit astringent, masticating the fruit in a juicer will result in a bitter juice. A cider press is recommended.

Approximately 14 to 16 lb of frozen fruit will yield one gallon of juice.  So a mature plant of about 5 or 6 years will give a gallon of juice or more.

The juice is rich in color with a distinct Aronia flavor, slightly tart.  Add some sugar if you wish.  Be prepared to freeze what you can’t drink in a few days, or your juice will ferment into a hard Aronia cider within a week.