Prime-Ark 45 blackberry variety

Rating [ 4.9 ]

Thorny, vigorous and prolific, two-season high-yielding blackberry variety with firm aromatic fruit

Botanical designation

Rubus subgenus Rubus Watson 'Prime-Ark 45'

Originated from a cross of

Originated from a cross of APF-12 x APF-1

Variety denomination

Variety denomination - 'APF-45'

Plants are

Plants are thorny

Bushes have

Bushes have erect canes

Fruit weight is

Fruit weight is 5 g


Berries have a conical shape

Fruiting habit

Fruiting habit - primocane-fruiting (everbearing)

Begins to bloom in the

Begins to bloom in the fourth week of April

Harvest season starts in the

Harvest season starts in the first week of June

Secondary blooming in the

Secondary blooming in the first week of July

Second harvest season in the

Second harvest season in the second week of August

Productivity is

Productivity is 5 kg per plant

Soluble solids

Soluble solids - 9.7%


Acidity - 0.51%

Cold hardiness is

Cold hardiness is moderate

Heat tolerance is

Heat tolerance is moderate

Country of origin

Country of origin - United States


Patent US PP22,449 P3 dated January 09, 2012

Current status

Current status - cultivated (actual)

Blackberry cultivar Prime-Ark 45 (APF-45) was introduced to broaden the choices of this innovative, thorned primocane-fruiting blackberry type.
This two-season type of blackberry fruits on current-season canes (primocanes) and on second-season canes (floricanes), potentially providing for two cropping seasons, both traditional summer fruits in addition to late summer to fall production. Traditional blackberry cultivars fruit on floricanes, requiring canes to be overwintered toproduce a crop. This fruiting habit has the potential to expand blackberry production much like that which has occurred for primocane-fruiting red raspberries.
In addition to having thornless canes, this Prime-Ark 45 produces large berries with good flavor and is very early ripening on floricanes. Berries of Prime-Ark 45 does not exhibit exceptional postharvest storage potential, and it is not recommended for the shipping market.
The average primocanes length is about 2 m. Primocanes are strong and vigorous, but thornly. Plants like sun placement. Prime-Ark's 45 berries are medium-large size, average weight of berry is about 4-6 g. Color is black. Each plant produces groups of berries, like bunch of grapes. The first yield starts forming at primocanes in the middle of June and continues three to four weeks. During this first harvest season, Prime-Ark 45 intensively produces primocanes, which soon begin bloom. This is the second harvest season, it continues up to first frosts.
After the end of the second harvest season, Prime-Ark 45 requires winter shelter from frost, freezing and cold wind, because the cold-hardy of this blackberry variety is moderate, about minus 13..17 C.
Table 1. Yield and average berry weight of Prime-Jim (APF-12), Prime-Ark 45 (APF-45) and floricane-fruiting varieties Ouachita and Natchez
Cultivar Yield, kg/ha Berry weight, g
2008 2009 2008 2009
Prime-Ark 45 13121 4194 6.1 4.7
Prime-Jim 6073 3759 4.6 3.5
Ouachita 8756 4012 5.8 4.7
Natchez 14113 5548 7.9 6.2
Prime-Ark 45 986 1565 4.3 5.1
Prime-Jim 84.1 146 3.2 3.3
Table 2. Comparison table of Prime-Ark 45 (APF-45), Prime-Jim (APF-12), Ouachita and Natchez cultivars at the University of Arkansas Fruit Research Station
Main features Variety
APF-45 APF-12 Ouachita Natchez
Floricane flowering date
10% bloom April 28 April 28 May 3 April 30
50% bloom May 4 May 5 May 8 May 4
Floricane harvest date
First June 10 June 8 June 13 June 5
Peak June 24 June 19 June 30 June 20
Last July 13 July 17 July 19 July 13
Primocane flowering date
First June 30 June 13 - -
Primocane harvest date
First ripe fruit August 8 July 15 - -
Fruit (rating scale of 1 to 10 where 10 is the best)
Firmness 8.1 6.6 8.1 7.7
Flavor 7.7 6.4 8.1 7.5
Soluble solids, % 9.6 8.8 10.5 9.2
Plant (rating scale of 1 to 10 where 10 is the best)
Vigor 7.4 7.6 7.0 6.8
Health 7.4 7.7 7.7 7.3

How to cultivate blackberry

How to cultivate blackberry Prime-Ark 45?

1. Avoid wet area when planted new bushes;
2. Annual spring nitrogen fertilization (56 kg/ha) using ammonium nitrate;
3. Additional fertilization (23 kg/ha) after the floricane crop production is completed in July;
4. Tipping primocanes at 42 inch height two times each season usually in mid-June and late July or early August;
5. Dormant pruning of primocane-fruiting plants must include removing dead floricanes and removing primocane tissue to a point below the fruiting (flowering) area on the primocanes;
6. Dormant pruning of floricane-fruiting plants must include removing dead floricanes and pruning lateral branches to ~ 0.4 m in length;
7. A single application of iron sulfate in late fall (October) and lime sulfur (94 L/ha) at budbreak in early spring;
8. Plant spacing at least 0.6 m;
9. Use sun shelters.
Diseases resistance

What diseases is blackberry Prime-Ark 45 resistant to?

Prime-Ark 45 has very good resistance to diseases such as Anthracnose
Diseases susceptibility

What diseases is blackberry variety Prime-Ark 45 vulnerable to?

No susceptibility to spicific pests or diseases has been observed for Prime-Ark 45
Relevant documents

Relevant documents for Prime-Ark 45 blackberry variety:

Useful Growing Guides

Useful Growing Guides:

Previous variety
Prime-Ark Freedom
Next variety

Reviews of the variety Prime-Ark 45

Review from [BERRY THAI]

แบล็คเบอรี่สายพันธุ์ prime ark45 สายพันธุ์ที่ให้ผลผลิตได้ดีในไทย ผลใหญ่ ดก รสชาติอร่อยถูกปาก

Review from [เกษตรริมรั้ว]

อัปเดตแบล็คเบอรี่ข้างบ้าน พันธุ์ prime ark 45 | ปลูกแบล็คเบอรี่


EMCO CAL - APF 45 Blackberry Variety - English Subtitles


Dr. John R. Clark describes Prime-Ark 45, the first primocane-fruiting blackberry with high quality storage and shipping characteristics for the commercial fruit industry. Prime-Ark 45 is the third of four primocane-fruiting blackberries released by the University of Arkansas System Division of Agriculture.

Review from [CLARKINKS]

We love prime ark 45’s they are beyond my best expecations. Not often does something exceed what we expected to extend the blackberry season. These pictures were taken September 10th. They show no signs of slowing down. They are still blooming! Prime ark freedom continue to be a dissapointment so far at my location. When people taste these test crop berries 100% of the time they say they are very good but not as good as my family heirloom berries that ripen in July. For extending the blackberry harvest these are exactly what you want. They are hardy but as hardy as the heirlooms. These must be very well cared for the first two years to get them established. My mother came out to look at them and after eating some she proclaimed they were pretty good for a tame berry but nothing like the family heirloom we grow. I mentioned to her that perhaps crosses between the two would improve the genetics on both. She looked at me like i suggested releasing tazmanian devils for a breeding project. If the heirlooms of my grandfathers blackberries pick up the everbearing gene naturally they would be unstoppable because the seeds readily sprout as it is with wide gentic variation.

Review from [CLARKINKS]

In my experience primeark45 in Kansas is truly everbearing with large , good tasting berries. Freedom thornless does ok but not as good as 45. I did not give them much special care to test how they truly would do in a really big planting. There are many more productive berries that can be planted if a single large crop is wanted. 45 is what should be planted for s continuos crop. The photo above was 25 days ago when these were mostly small berries and blooms. These test crops of Prime ark 45 turned out very good! Freedom planted at the same time did not produce berries. Primeark 45 had some large berries even on these smaller plants. The berries started ripening in Late June (ate a few) and are still producing today on July 4th! They may produce up until the time of my main blackberry harvest on July 20th. These are all good signs but we will see what fall brings! These are Very very promising black berries! Flavor and disease resistance have been very good. These look like they will fit my needs extending the blackberry harvest.

Please login or register to write reviews!

Discussions about variety Prime-Ark 45

No comments yet

Please login or register to post comments!