Hello fellow plum growers! I often get inquiries from others on the forum who are seeking varieties they should add to improve cross pollination of their existing stonefruit varieties. We know that a good pollinator is one that produces compatible pollen and has a blossom schedule that is in close match to the variety a member may already be growing. The intent of this Google Form is to create a ready data source that members in any growing zone can reference for the blossoming data of all varieties that other members have submitted.
Compatible pollen: We know that Asian plums varieties have pollen compatible with other Asian varieties as well as most Native American plums (p Americanna) and most European plums are pollinated by other European (P domestica) varieties. Native plums of P Americana are compatible with hybrids of natives, and most Asian plums. Plumcots are compatible with other Plumcot varieties as well as the Asian plum in their heritage. If you are entering data for a hybrid cross and know the varieties the breeder used to create the hybrid please enter that data under Genus to help other members in their use of your data. Hybrids crosses are a bit trickier. Here are just a few sources from online searches:
- Oregon State University provides this information: “ Pluots, like plums, will also need a pollinizer of a different variety to ensure a good fruit set. Most pluot varieties will pollinate another pluot variety. Another option is planting certain varieties of plum to pollinate the pluot. Plant a Japanese plum tree within 100 feet of the pluot for cross-pollination. Although a pluot is part apricot, another apricot will not serve as a pollinator.”
- Methley one of the best cross pollinators due to its hybrid heritage: “The Methley Plum Tree actually has a very interesting history in that it is believed to be a Hybrid between an American Plum variety (Prunus cerasifera) and the Japanese Plum (Prunus salicina). This happened unintentionally as a select seedling in South Africa around the turn of the 20th century.” Since so many plum varieties have been bred from crossing other Asian plums with P cerasifera and P cerasifera has befound on most continents, it’s often used in plum breeding and is therefore one of the universal choices for cross pollination.
- Another source states: “Hybrid plums require a specific second variety for pollination (see variety charts). For example, in order to get fruit from an Alderman plum, you would have to plant either a Toka or Superior plum as well (or a native American or Canadian plum). European plums and tart cherries are self-compatible.”
- Will a pluot tree pollinate a plum tree? “Pluots are generally larger than plums and higher in sugar content; they are a flavor delight. Pluots, like plums, will need a pollinator of a different variety for good fruit set. Most will pollinize with another pluot, or certain varieties of plum.”
The other consideration in using data from another growing zone is that a variety may alter its blossoming schedule when taken to another climate zone. So if I am in zone 8A I would like to obtain data from a nearby grower or preferably one and the same zone. But if the data I want is available only from another zone, it’s is useful to determine how many days of delay should be used to adjust the blossoming data from the other zone. This can easily be done by comparing the data of a common variety in each zone.
In closing this is a trial and my first time creating a Google form, so I may need to tweak it to assure data is being recorded in a usable spreadsheet format.
The spreadsheet is automatically updated as you make a data entry on the Form. And it can be opened by any member for reference even though it says it’s Private!
It best to write down your complete schedule with the date of each event: balloon thru petal fall. Then make your data entry, so a complete record is recorded on the spreadsheet. You cannot add the data later since the spreadsheet is closed and is read only! The entry I made for Cherry plum was before petal fall so that data cannot be revised once the event actually occurs.
Any feedback for improvements are welcomed
Dennis Kent, wa