Garden Mastery Tips
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June 2007 |
Evolution in Hydrangea Horticulture
On September 11, 1998, one of the most significant recent discoveries in the propagation of new varieties of hydrangeas occurred in St Paul, Minnesota. Dr. Michael A. Dirr, a world renowned expert on hydrangeas and a professor of horticulture at the University of Georgia, was present at new plant trials at Bailey's Nurseries. To his surprise he discovered a row of Hyrdangea macrophylla in full flower. With the severity of winter in St. Paul (temperatures of -20 to -30 degrees F) no previous macrophylla was cold hardy enough to survive and flower without protection. It was apparent that this plant was a rarity in that it produced blooms on both old and new growth.
For the next five years extensive hybridization using cuttings of this plant were conducted by Dr. Dirr. He cross bred them with several other hydrangea varieties. His test plants were mildew resistant and had very desirable foliage and form. Most importantly, the key trait of romontancy (repeat blooming) was consistently passed along in the testing and hybridizing process. A completely new variety that was cold hardy in zone 4 was created. Dr. Dirr named it Endless Summer and Bailey applied for and received a plant patent. This newly created mophead produced medium green leaves and a delightful and substantial pink bloom with remontant flowers on new as well as old growth. Previously Dr. Dirr had traveled extensively in both Europe and the United States in an attempt to identify and test countless plants for remontancy, but no true remontants were found. This essentially confirmed an entirely new genetic finding and led Bailey and Dr. Dirr to proceed with organizing a consortium of growers to produce and introduce a million Endless Summers in 2003. This partial release was followed by a full release in 2004.
From 2001 through 2004 controlled crosses were continued by Dr. Dirr. His efforts using Veitchii x Endless Summer produced a beautiful white mophead complete again with remontancy and survival in St Paul zone 4 winters. This new variety was named Endless Summer Blushing Bride because the pure white mophead gradually turns to light pink as it matures.
We planted Endless Summer in Vancouver, Washington in 2004. We now have a beautiful mature plant with pink blooms growing in a location that is well-drained, is highly organically enriched and has a ph of 6-0. The plant blooms can be turned blue with the addition of a light amount of aluminum sulfate used as directed on the container.This spring we planted a 3 gallon potted Endless Summer Blushing Bride and am looking forward to what appears to be another wonderful addition to the garden.
References
Dirr, Michael A. Hydrangeas for American Gardens,Timber Press, 2004.
"Endless Summer." Retrieved May 30, 2007 from http://endlesssummerblooms.com/en/home
Nursuries
Tsugawa Nursery Greenhouses, Woodland, WA 98674 (360)225-8750 http://www.tsugawanursery.com
Wayside Gardens. http://waysidegardens.com