Solutions for Underblooming Endless Summer Hydrangeas

Endless Summer Hydrangeas photo from the Endless Summer site

I've spoken with a few gardeners here in the northern regions who are dismayed with the flowering of their Endless Summer Hydrangeas.  (see http://shirley-agardenerslife.blogspot.com/2010/09/fertilizer-friday-flaunt-stages-of-pink.html) The unique quality of this hydrangea of blooming on new and old wood appealed to many in the harsher regions.  Zones 3, 4 and 5 sometimes find it more difficult to grow certain species of hydrangea, especially those with colourful blossoms.  When Endless Summer was introduced a few years ago we thought we found the one plant that offered what we sought!  Blue in acidic soil and pink mophead blooms in alkaline, these gorgeous plants flew out the nursery doors. 

photo from Endless Summer site

Annabelle, Tardiva, Pee Gee and Limelight Hydrangeas all thrive here with minimal fuss but they lack the shock of pink and blue blossoms northern gardeners crave.  Hydrangeas typically do well with morning sun and shade in the afternoon.  Annabelle do great on the north side of the house!  So, the thinking was Endless Summer would/should too, right? 

Endless Summer require at least six hours of direct sunlight to flower well.  They need to be mulched heavily after the first hard autumn frost.  Growers of this hydrangea have a few more pieces of advice to offer:  Don't cut back your hydrangea in the fall or early spring, wait for new growth.  Don't remove the mulch until the end of May and then do so a bit at a time.  Late spring frosts can damage new growth and flower buds, much like apples and plums.  Don't overwater!  Yes, hydrangeas do require more water than most plants but overwatering actually prevents this plant from forming flower buds.  The growers tell us that it is normal for this hydrangea to wilt a bit in the heat of the day and perk up in the evening as the temperature drops.  And of course, fertilize!

For more tips see http://www.mahoneysgarden.com/blog/solutions-your-underblooming-endless-summer-hydrangeas.

my Endless Summer 2009

Here in Alberta, some areas haven't yet received a heavy frost but once we do we need to mulch this hydrangea heavily.  You may desire to use a rose hut (a Styrofoam hut) available from most garden centers.  I know one gardener who uses chicken wire to form a fence around the perimeter of each of his hydrangeas and then he fills it with shredded leaves, covering the entire plant.  He swears by this.  Also folks, water in well in the fall to form an ice block to prevent the heaving of soil and roots as the soil freezes and thaws in the spring.

I recently moved my underperforming Endless Summer to the south side of my house.  The soil warms faster there in the spring and this area receives full sun for at least six hours a day.  I'll let you know how it goes.

http://www.endlesssummerblooms.com/en/consumer
http://shirley-agardenerslife.blogspot.com/2010/03/twincitieslivecom-bailey-nursery.html