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NEIGHBORHOOD GARDEN FOR FEBRUARY 16, 2008
************************************************************* HYDRANGEAS PART #1 BY GEORGE EDGAR
·
“Should I plant my
HYDRANGEA in full sun, part
sun, or shade?”
It depends. ·
“Will my HYDRANGEA
bloom in the spring, in the summer, or the
late summer?”
It
depends. ·
“When do I prune my
HYDRANGEA?”
It
depends.
I
say “It depends” because there are thousands of varieties of
Hydrangea and where you plant your Hydrangea, how you grow it, how you
fertilize, when it blooms, what color the bloom will be, and when you
prune it depends on the specie and variety you are growing. . In his new
book on Hydrangea, Dr. Michael S. Dirr, professor of horticulture at the
University of Georgia and recognized international expert on trees and
shrubs, has chapters on each of the 9 major species of Hydrangea. In
Chapter 11 he mentions many more minor species that are found around the
world. (See Resources at end.) As
the fly cover of his book says, “The sheer number of Hydrangea
species, hybrids, and cultivars can prove overwhelming even for the most
advanced gardeners. How to
choose from the hundreds of mopheads, lacecaps, climbers, and oakleafs,
to names just a few?” Gladys and I
write most articles from our experience with the subject. This one is
different in that both Gladys and I have very little personal experience
with growing Hydrangeas. I started my reading as I had a hard time
successfully growing a Hydrangea macrophyla ‘Nikko Blue’. I wanted
that blue flower but could not even get it to flower let alone turn
blue. I asked around and a few people gave me suggestions why. Then I
tried to find someone to write this article and came to a dead end so I
began to research why they would grow but not flower. Today I will
share with you what I have learned from my reading. One expert wrote
“Hydrangeas do not usually bloom because: (1) Too much pruning, (2)
improper pruning time, (3) weather--too cold or the transition to and
from winter/summer too drastic, (4) too much shade, or (5) too much
nitrogen fertilizer.” (Hydrangeas Plus newsletter for
November/December 2007) I think number
3, the weather, is probably the biggest reason most Hydrangea macrophyla,
especially in Southeast and South Central Nebraska, do not bloom. As I
look back, I know this was why my Hydrangea macrophyla did not bloom. I found an
article in the “Horticulture and Home Pest News” from Iowa State
that had the best description of why certain Hydrangeas don’t bloom
and also about other Hydrangeas that are good for the Upper Midwest and
zone 5. The following is from that article “Hardy Hydrangeas” by
Cindy Haynes, Department of Horticulture, Iowa State University,
Horticulture and Home Pest News for June 22, 2001. “The Big Leaf
Hydrangea (Hydrangea macrophyla) is the colorful shrub we see in florist shops
and super markets and desire in our landscape. One variety is referred
to as a “snowball plant” because of its big round flower. However,
this variety of Hydrangea is not hardy in zone 5. It will grow but the
Big Leaf Hydrangeas bloom on previous season’s growth (old wood) and
since the stems often die back to the ground in the winter, they seldom
bloom. Even placement in a
protected site with fertile, moist, well-drained soil, will not
guarantee blooms every year.” “But wait!!!
Don’t give up on Hydrangeas yet. There are a wonderful group of summer
blooming shrubs with several species that are hardy in our zone 5. These
include the Smooth Hydrangea (Hydrangea aborescens) that flowers freely
from June to September. The flowers are rounded and change from an apple
green to cream white during the summer. ‘Annabelle’ is one of the
most popular cultivars and noted for its large (almost 1 foot diameter)
flower heads.” According to
Dr. Michael A. Dirr in his book on Hydrangeas, “The Smooth Hydrangea
(Hydrangea arborescens) will reliably produce flowers in gardens from
Alberta, Canada, to North Florida. The most common variety is
‘Annabelle’. At a certain stage the big flowers are green in color
and prized by those who prepare and arrange dry flowers as well as
fresh. Most seeds of ‘Annabelle’ produce sterile-flowered, globose
(globe shaped) to round-shaped, white, mophead offspring.” In spite of
this problem with the seeds, Dr. Dirr has a goal to breed a pink type of
‘Annabelle’. A friend, Bob
Henrickson who lives here in Lincoln and works a great deal with trees
and shrubs for the Nebraska Statewide, has shared the following, “The
Smooth Hydrangea ‘Annabelle’ does not tolerate drought very well,
and consistent moisture and rich, organic soils should be encouraged for
optimum bloom.” Many garden
centers and especially box stores, hardware stores and drug stores sell
“Hydrangea macrophylla” as hardy in zone 5. It is but beware as it
probably will not bloom every year. One exception is the new variety
called “Endless Summer” that was developed by Bailey Nursery in
Minnesota and fully released in 2004. This variety blooms on both old
wood (last season’s growth) and new wood (this year’s new growth)
and is hardy to zone 4. It is becoming a very popular shrub and new
cultivars are coming out each year, including ‘Blushing Bride’, a
pink variety of ‘Endless Summer’. You might want to try one. In Hydrangeas
Part #2 I will deal with some more varieties of Hydrangea that will do
well in our area, and then in Part #3 will deal with fertilization and
pruning. RESOURCES: ·
“Hydrangeas for the
American Gardens” by Michael A. Dirr, (Timber Press: Portland) 2004 ·
“Hardy Hydrangeas” by
Cindy Haynes, Department of Horticulture, Iowa
State University, Horticulture and Home Pest News for June 22,
2001. ·
HydrangeasPlus.com
newsletter (Hydrangeas Plus: A division of VanHoose Enterprises, LLC,
and P.O Box 389, Aurora, OR 97002) ·
Hydrangea.com (Wilkerson
Mill Garden, Palmetto, GA 30268) ·
“Pruning Hydrangeas”,
Fine Gardening Magazine, The Taunton Press: Newtown, CT 06470-5506,
May-June 2007, pages 51-53.
Copyright 2008 |