Flowering and Fruit Characteristics of Black Walnuts: A Tool for Identifying and Selecting Cultivars
|Budbreak||Average first pistillate bloom date||Mean pistillate bloom date||First pollen shed date||Flower type||Season length||Harvest date|
|Beck||April 28||May 15||May 21||May 16||Protogynous||128 days||Sept. 25|
|Bowser||April 29||May 9||May 14||May 19||Protogynous||128 days||Sept. 17|
|Brown Nugget||April 16||April 27||May 1||May 10||Protogynous||131 days||Sept. 8|
|Cranz||April 29||May 19||May 21||May 11||Protandrous||130 days||Sept. 27|
|Crosby||2 May 2||May 10||May 19||May 20||Protogynous||142 days||Oct. 3|
|Davidson*||April 12||April 23||April 28||May 9||Protogynous||132 days||Sept. 4|
|Drake||April 28||May 6||May 13||May 15||Protogynous||151 days||Oct. 9|
|Elmer Myers||May 1||May 10||May 17||May 23||Protogynous||128 days||Sept. 18|
|Emma K||April 20||April 23||April 30||May 6||Protogynous||148 days||Sept. 23|
|Football||April 15||April 27||May 1||May 6||Protogynous||156 days||Sept. 30|
|Grundy||April 20||May 10||May 12||April 28||Protogynous||122 days||Sept. 13|
|Hare||April 29||May 7||May 16||May 20||Protogynous||143 days||Sept. 30|
|Harney||April 27||May 8||May 15||May 16||Protogynous||133 days||Sept. 26|
|Hay||May 5||May 14||May 22||May 24||Protogynous||135 days||Oct. 3|
|Higbee Mill||May 4||May 17||May 27||May 25||Protogynous||131 days||Oct. 2|
|Jackson||April 16||April 27||May 2||May 9||Protogynous||155 days||Sept. 28|
|Knuvean||April 18||May 11||May 17||April 29||Protandrous||136 days||Oct. 1|
|Kwik Krop||April 26||May 5||May 9||May 18||Protogynous||148 days||Oct. 3|
|Mintle||April 17||May 14||May 19||May 1||Protandrous||129 days||Sept. 23|
|Mystry||April 16||April 29||May 4||May 11||Protogynous||141 days||Sept. 19|
|Neel #1||May 3||May 12||May 21||May 21||Protogynous||141 days||Oct. 5|
|Ness||April 16||April 27||April 30||May 10||Protogynous||168 days||Oct. 12|
|Ogden||April 23||May 6||May 10||May 13||Protogynous||168 days||Oct. 18|
|Ohio||April 24||May 7||May 8||May 15||Protogynous||140 days||Sept. 18|
|April 16||April 25||April 30||May 6||Protogynous||153 days||Sept. 28|
|Pound #2||April 24||May 8||May 17||May 20||Protogynous||143 days||Oct. 1|
|Pritchett||April 18||April 28||May 6||May 12||Protogynous||134 days||Sept. 14|
|April 28||May 7||May 13||May 20||Protogynous||145 days||Oct. 2|
|April 25||May 4||May 9||May 15||Protogynous||141 days||Sept. 25|
|Sauber #1||April 26||May 6||May 14||May 18||Protogynous||134 days||Sept. 20|
|May 8||May 14||May 17||Protogynous||118 days||Sept. 5|
|Schessler||April 13||April 22||April 29||May 6||Protogynous||129 days||Sept. 4|
|April 27||May 10||May 14||May 15||Protogynous||117 days||Sept. 5|
|Shreve||May 2||May 8||May 17||May 17||Protogynous||147 days||Oct. 4|
|South Fork||April 14||May 9||May 6||April 28||Protandrous||158 days||Oct. 8|
|Sparks 127||April 25||May 7||May 12||May 16||Protogynous||118 days||Sept. 4|
|Sparks 129||April 23||April 27||May 6||May 15||Protogynous||125 days||Sept. 28|
|Sparks 147||May 3||May 11||May 15||May 18||Protogynous||131 days||Sept. 21|
|Sparrow||April 26||May 11||May 13||May 16||Protogynous||119 days||Sept. 6|
|Surprise||April 25||May 6||May 10||May 15||Protogynous||143 days||Sept. 30|
|Thomas||May 2||May 6||May 15||May 21||Protogynous||145 days||Oct. 2|
|Thomas Myers||May 5||May 11||May 21||May 21||Protogynous||131 days||Sept. 26|
|Tomboy||April 18||April 27||May 1||May 9||Protogynous||135 days||Sept. 10|
|Wiard||April 28||May 14||May 24||May 9||Protandrous||125 days||Sept. 21|
*Davidson cultivar is not pictured.
- Fingerprint alias
Some cultivars with different names are genetically identical as determined by DNA fingerprinting. Where this occurs among the cultivars listed in the table, "cultivar name" is the name thought to have been assigned first; "fingerprint alias," later.
The average date of budbreak is the time when the tips of leaves are visible from swollen buds. Female or pistillate flowers develop at the tips of the new growth, while male or staminate flowers are produced on catkins on one-year-old growth.
- Pistillate bloom dates
Pistillate bloom occurs over a period of several days. Thus, date of first pistillate bloom is important in selecting cultivars that will avoid injury due to late-season frosts. The mean (average) pistillate bloom date is when female flowers are most likely to be receptive to pollen.
- First pollen shed
Mean dates of pollen shed are important because these dates must coincide with pistillate bloom and receptivity for effective cross-pollination and subsequent fertilization to occur.
- Flower type
Black walnut cultivars exhibit two flowering habits. Protogynous cultivars are those that produce pistillate flowers before the staminate flowers. Protandrous cultivars produce staminate flowers on catkins before the pistillate flowers are visible.
- Season length
Season length is the number of days from the mean pistillate bloom date to the date of harvest.
- Harvest date
Average date of harvest is the date by which nuts are suitable for harvest.