US Plant Patent PP15399
Royal Kay
Cherry tree named ‘Royal Kay’
PUBLIC DOMAIN
Patent expired February 26, 2023. This plant is in the public domain — anyone may propagate and sell it.
Twenty years from the filing date would end on November 25, 2022. This patent earned 93 days of term adjustment for delay at the Patent Office, which is why it runs longer.

The record
- Patent number
- PP15399
- Filed
- November 25, 2002
- Granted
- December 7, 2004
- Expires
- February 26, 2023
- Inventor
- ZAIGER GARY NEIL; GARDNER LEITH MARIE; ZAIGER GRANT GENE
Abstract
A new and distinct variety of cherry tree ( Prunus avium ). The following features of the tree and its fruit are characterized with the tree budded on ‘Mahaleb’ Rootstock (non-patented), grown on Handford sandy loam soil with Storie Index rating 95, in USDA Hardiness Zone 9, near Modesto, Calif., with standard commercial fruit growing practices such as pruning, thinning, spraying, irrigation and fertilization. Its novelty consist of the following combination of desirable features: 1. Vigorous, upright tree growth. 2. Fruit maturing in the early season. 3. Fruit with attractive red skin color. 4. Heavy and regular production of large size fruit. 5. Fruit with very good flavor and eating quality. 6. Fruit with good handling and storage quality.
Show the legal claimThe single numbered claim as granted — the legal text that defines what this patent covers.
It is claimed: 1. A new and distinct variety of cherry tree, substantially as illustrated and described, characterized by its large size, vigorous, upright growth and being a regular and productive bearer of large size fruit with very good flavor and eating quality; the fruit is further characterized by its attractive red skin color and by maturing in the early season with good handling and shipping qualities, and in comparison to ‘Early Burlat’ Cherry (non-patented), the new variety blooms approximately 7 days earlier and the fruit is approximately 3 days earlier in maturity.
Read the full patent: US Plant Patent PP15399 in full — the complete specification, every figure, and the file history.