Hydrangeas for Alkaline Soil

 

 

     Hydrangeas are a plant most people associate with the Pacific Northwest with its humid climate and acid soil, not southeast Idaho with its dry climate and alkaline soil. But there are some varieties of hydrangea that are adaptable enough to grow well here. The following are a few varieties I've had enough experience with to vouch for.

 

Endless Summer Hydrangea

(Hydrangea macrophylla 'Bailmer')

 

     

      I was skeptical when I first saw this hydrangea being sold in nurseries in this area. It is a Hydrangea macrophylla, a species of hydrangea that is not particularly adaptable. But happily time has proven me wrong. I have a neighbor who has been growing several of these bushes successfully for over five years. Bear in mind that the flowers on these bushes are blue in the nursery, but they will turn pink when growing in alkaline soil. With consistently repeated applications of soil acidifier it might be possible to keep the flowers blue, but for most gardeners it wouldn't be worth the effort, since the pink flowers are beautiful as well.

 

 

Hydrangea paniculata

 

     Hydrangea paniculata is the most adaptable species of hydrangea and grow well in alkaline soil. Any variety of hydrangea whose latin name begins with Hydrangea paniculata (sometimes abbreviated as Hydrangea p.) can be counted on to do well in southeast Idaho.

     It used to be that the only color options for paniculatas was white, but thanks to plant developers that has changed. New varieties are being developed all the time.  Here are a some of my favorites.

 

 

Quick Fire Hydrangea

(Hydrangea paniculata 'Quick Fire')

 

 

 

        Quick Fire hydrangeas have loose white blossoms that turn to pink. They are tough shrubs that bloom on new growth, so they will still bloom even if they suffer some winter kill.

Pinky Winky Hydrangea
(Hydrangea paniculata 'Pinky Winky')

 

 

       The flowers on Pinky Winky hydrangeas grow in long cone shaped panicles. Like Quick Fire, the flowers start out white and turn pink. And again, like Quick Fire, Pinky Winky blooms on new growth, so will bloom even if they suffer some winter kill

 

      Vanilla Strawberry (Hydrangea paniculata 'Vanilla Strawberry') is similar to Pinky Winky. Nurseries usually either carry one of these varieties or the other, but not both.  

 

 

Little Lamb Hydrangea

(Hydrangea paniculata 'Little Lamb')

 

 

 

     Little Lamb sports large, fat panicles of white, fluffly looking flowers, said to look like little lambs, hence the name. It is a tough bush, hardy to zone 3.

 

 

 Tips for Growing Hydrangeas in Southeast Idaho's Climate

 

 

     Hydrangeas bloom from mid-summer into fall, and so are great for adding late season interest to the landscape, but keep a few things in mind when growing them in southeast  Idaho.

 



      With the alkaline soil, low humidity, and short growing season we have in this area, hydrangeas usually do not grow as big here as they do in the Pacific northwest. The tags on Endless Summer say it will grow to be 3-5' tall and wide. The largest of my neighbor's bushes is barely 3'. So plan on the low end of the mature size.

 

     The tags on hydrangeas sometimes say they can be grown in full-sun to part shade, but in our area, with our intense sun, part to full (though light) shade is best.