Dr. Michael A. Dirr--On Hydrangea Breeding and Improvement
Watkinsville Garden Plant Sale Offers Unique Hydrangeas

Frank Johnson requested a few words about the process involved in hydrangea breeding and improvement. You may know our company, Premier Introductions, Inc. (PII), worked with the Watkinsville Garden Club (WGC) in 2017-18 and assisted the members in growing approximately 300 hydrangeas for the Club’s annual plant sale. According to Frank, who managed the entire growing and sale operation, the hydrangeas were sold out in 23 minutes.

So here we are in 2022 with another WGC hydrangea sale coming up on May 7th. These hydrangeas were residuals from PII’s 2021 breeding and evaluation. The company’s breeding goals are moving targets and every year we hope to improve on the previous year’s successes. Goals include large showy flowers, repeat flowering through the growing season, strong stems to carry flowers upright, disease resistant, dark green, heat tolerant foliage, cold hardiness, and, yes, deer resistance. The breeding process is a journey and the destination, to date, has not  been completely reached after 40 years of focused effort.

Crosses are made between the parents that give the best opportunity to produce progeny that inherit the quality traits mentioned above. Pollen is transferred from the male parent to the female typically in the May-June flowering period. Plants are monitored for health to foster fruit and seed development. Fruits are collected in November-December, dried in paper bags, crushed with a rolling pin (yes, a rolling pin), and contents passed through a series of sieves until only the tiny seeds remain. Seeds are stored in glass jars until sown in December and January on a peat-perlite based medium. Seeds germinate in 10 to 21 days and are transplanted to small cells, then transplanted to 3-gallon containers in April. If all goes well, many seedlings will flower the first growing season which indicates that they should be partially to fully remontant/reblooming. In 2021, 393 flowered out of a total of 3,745 seedlings. Those that did not flower will do so this year (2022).

Of the 3,745 hydrangeas we grew in 2021, PII only selected the 393 that flowered last year for further evaluation.  The question then becomes, what did PII do with the remaining 3,352? The answer is the WGC had the opportunity to handpick 250 of the best of those 3,352 plants and will have them available for the May 7th plant sale. These represent seedlings from approximately 30 crosses that will not have been observed in flower by anyone except the fortunate person who purchases one at the plant sale. These plants have never been on Planet Earth before and represent the mixing of genes from the best parents in the hydrangea world. This is an opportunity to add a magnificent hydrangea to the garden. When visitors ask, “Where did you buy that?”  The immediate response should be, “The Watkinsville Garden Club.”

WGC looks forward to your support of their plant sale which will take place on May 7th from 9:00 am to 1:00 pm next to Oconee State Bank, 35 N. Main Street, Watkinsville.

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Dr. Michael Dirr