Got dry shade?  We’ve got solutions.

Got dry shade? We’ve got solutions.

  • By Cathy Caldwell
  • /
  • July 2018 - Vol.4 No.7
  • /
  • 2 Comments

Are you looking for a plant that can thrive in dry shade?  Yes, there is such a thing.  In fact, there is more than one, but I’m going to start by giving a big shout-out to the one I know best, Geranium x cantabrigiense ‘Biokovo’ — which has been a stalwart ground cover under cedars in my front yard.  If you have cedars, you know they gulp up all the moisture anywhere in the vicinity. And you might have wondered if anything can thrive under them — or should I say “over” them, since the problem is the cedar’s roots, and anything planted over those roots has a daunting competitor.

I started with one Biokovo geranium many years ago, plopped it down under the dense shade of cedars (that I could not convince my husband to cut down), and ignored it while I busied myself with my young children.  That one little plant spread happily, healthily, and with nary a sign of deer or rabbit browsing, and now that my children are grown, it occupies a large swath with no sign of age or decline.  Wish I could say the same for myself!

Geranium x cantabrigiense ‘Biokovo’
Photo: Cathy Caldwell

Geranium x cantabrigiense ‘Biokovo’ 

But before I gush on about this geranium, let’s get our terms straight.  ‘Biokovo’ is a true geranium, sometimes referred to as a hardy geranium so as not to be confused with the summer bedding plants, sometimes called zonal geraniums, which are actually Pelargoniums.  The true geraniums are also commonly called cranesbills.

Now back to my beloved ‘Biokovo’  — a low, mounding perennial with pale pink blooms in late spring, and evergreen foliage that turns scarlet and copper in fall.  Geranium x cantabrigiense is a sterile hybrid geranium developed in 1974 by Dr. Helen Kiefer of the Cambridge University Botanic Garden in Cambridge, England, by crossing G. macrorrhizum (the bigroot geranium discussed in detail below) and G. dalmaticum. The cultivar ‘Biokovo’ was a naturally-occurring hybrid discovered in the Biokova Mountains in Croatia. www.missouribotanicalgarden.org/PlantFinder.

‘Biokovo’ geranium makes a good “spiller” on a semi-shady walkway.

 

The blooms of ‘Biokovo’ are actually white with a tinge of pink and darker pink stamens, but the overall effect is that of a blush pink.  You will get a few repeat blooms if you shear off the flower stems after blooming, but it’s not necessary.  This plant has gotten almost no care from me, although after about 15 years of neglect, it occurred to me to give it a thin layer of compost.  Since it chokes out weeds — even the vinca minor that impeded its path —  I have almost never had to weed it.  So basically this plant can thrive in whatever situation it finds itself — including the poor, dry soil under my cedars.   I’m sure this plant will do the same in all manner of dry, shady conditions.  No surprise that ‘Biokovo’ was named the 2015 Perennial Plant of the Year by the Perennial Plant Association.  See news.aces.illinois.edu/news/2015-perennial-plant-year-geranium-x-cantabrigiense-‘biokovo’.

Bigroot geraniums

‘Bevan’s Variety’ bigroot geranium, courtesy of Cornell University.

There are other true geraniums that are well-known for the same characteristics as ‘Biokovo’ — including many of the so-called “bigroot geraniums,” whose scientific name is Geranium macrorrhizum.  These plants are very similar to their cousin ‘Biokovo’ — although this type can apparently spread by self-seeding, while ‘Biokovo’ spreads only via its rhizomes.  My research indicates that the bigroot geraniums are big favorites of many gardeners and garden writers.

There are several bigroot cultivars to consider:

Geranium macrorrhizum ‘Bevan’s Variety’  has a magenta bloom and is about 1 foot tall.   For more information, check out this plant’s profile at www.missouribotanicalgarden.org.

‘Ingwersen’s Variety’ has pale pink blooms —  like ‘Biokovo’ —  and is about 18″ tall.  See more about this cultivar at www.missouribotanicalgarden.org/PlantFinder.

Cornell University lists the following additional cultivars to try:

‘Album’:  1′ tall plants with white blooms with showy pink stamens.

‘Czakor’:  1′ tall plants with magenta blooms. Purple autumn leaves.

‘Spessart’: deep pink blooms that produce showy seedheads.

— “Geranium, Bigroot,” Cornell Univ.Growing Guide,  www.gardening.cornell.edu/homegardening.

 

Epimedium x youngianum ‘Royal Flush’

Epimediums

Epimediums, commonly called bishop’s hat or barrenwort,  are another easy-care groundcover that can manage quite well in dry shade.  For an extremely informative article on epimediums, look no farther than a past issue of The Garden Shedpiedmontmastergardeners.org/epimediums, by Pat Chadwick.  Pat knows her epimediums! For information about recommended varieties, you can rely on Pat’s article.  According to the Missouri Botanical Garden, epimediums tolerate rabbits, deer, drought, heavy shade, erosion, dry soil, and shallow-rocky soil.  Need we say more?!

 

 

Variegated Solomon’s seal makes an upright background for ‘Biokovo’ geranium

Solomon’s seal (Polygonatum)

Solomon’s seal is part of a large genus of rhizomatous plants that has managed quite well in my under-the-cedars garden.  It is grown mostly for its foliage, and the variegated type — Polygonatum odoratum ‘Variegatum’ — is deservedly popular.  There are quite a few varieties to choose from, and you’ll find a helpful listing in an article on the Wisconsin Master Gardeners website, wimastergardener.org

 

 

 

 

 

Hellebores 

Hellebores are recommended for dry shade, and I have had good luck with them under my cedars.  The genus Helleborus contains about 20 species and subspecies.  I’ve grown both the Helleborus orientalis (sometimes called Lenten rose) and the so-called “stinking hellebore” — Helleborus foetidus.  It’s the latter that I just adore.   The common name stinking hellebore comes from foetidus, which is Latin for fetid or foul smelling, but I’ve never smelled a thing, though I’ve read that there is a musky odor if you brush against the foliage or bloom stalks.  This plant is truly amazing both for its large, dramatic chartreuse flower stalks and its long bloom time, from late January into May.

Stinking hellebore at the Cambridge University Botanic Garden. Photo: Magnus Manske

Go Native

The native species of hardy geranium is sometimes called spotted cranesbill (Geranium maculatum) is not familiar to me, but if you find it works in your dry, shady garden, please let me know.  I’d like to try it.

And don’t forget our native ferns, several of which are good options for dry shade, including:

  • Christmas Fern (Polystichum acrostichoides)
  • Hay Scented Fern (Dennstaedtia punctilobula), which is an agressive spreader that can form colonies that smother weeds, according to that handy handbook, Piedmont Native Plants: A Guide for Landscapes and Gardens, published by the Thomas Jefferson Soil & Water Conservation District as a supplement to the website, Piedmont Native Plants Database, www.albemarle.org/nativeplants.

For a longer list of plants — including a few shrubs — that can handle dry shade, I recommend an article titled “Problem Solver Plants for Dry Shade,” on the Missouri Botanical Garden website, www.missouribotanicalgarden.org/help-for-the-home-gardener/advice-tips-resources/visual-guides/-plants-for-dry-shade

 

SOURCES:

Piedmont Native Plants: A Guide for Landscapes and Gardens, published by the Thomas Jefferson Soil & Water Conservation District as a supplement to the website, Piedmont Native Plants Database, www.albemarle.org/nativeplants (searchable). Note:  The TJSWCD has this guidebook for sale, $10 each,  at 434-975-0224, Ext. 102, or email mary.eiserman@tjswcd.org.

“2015 Perennial Plant of the Year Geranium x cantabrigiense ‘Biokovo’,” news.aces.illinois.edu/2015-perennial-plant-year-geranium-x-cantabrigiense-‘biokovo’

“Perennials for Dry Shade,” Ill. Ext., extension.illinois.edu/perennials/DryShade

“Geranium, Bigroot,” Cornell Univ.Growing Guide,  www.gardening.cornell.edu/homegardening

www.missouribotanicalgarden.org/PlantFinder/geranium macrorrhizum

“Elegant Epimedium—Foliage and Flowers of Subtle, Sophisticated Beauty,”
by Barbara Blossom Ashmun, www.BrooklynBotanicGarden.org/epimedium (2007)

“Epimedium,” The Garden Shed, piedmontmastergardeners.org/article/epimedium/

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