Shade tolerant clumping grass

(Question)

I want to grow something 8-10ft tall along about 8 feet of my fence line, to create privacy. I have sandy soil. The area is shady. I want fast growing. I’m not fond of cedars. Want something clumping so it won’t spread under fence or into pathway. I live in Mississauga, near Rattray Marsh (zone 6). I was looking for a clumping bamboo or attractive grass with hope of fast growing. If nothing like that is available in this area, maybe a vine but concerned about controlling spread. Any suggestions please? Thanks very much! Ruth

(Answer)

 

Hello, thank you for contacting the Toronto Master Gardeners for suggestions on your planting.  I am gratified to see that you are concerned about biodiversity loss and the impact that invasive species might have, especially near a delicate conservation area such as Rattray Marsh.

I appreciate that cedars are probably the “go-to” solution offered by most garden centers, but I believe you can find something else that will fit the bill, visually and yet mindful of the environment.

Let us first look as grasses, as this was your first choice.  I would steer clear of Miscanthus, as some varieties will spread, but also, they will not relish a shady, nor a sandy spot.  Instead look for moor grass (Molinia spp).  This grass does well in semi shade and can handle average garden soil.  They form a tidy clump of foliage and the long-stemmed flower heads can reach up to 6 feet in certain varieties.  Another excellent choice for your site would be Andropogon gerardii (Big bluestem).  This prairie grass can tolerate semi shade and does well in sandy, well drained soil with low fertility.

You also mentioned climbers. There are a couple that do well in a shady situation, but, like most plants suited to shade, are slow growing.  Climbing Hydrangea is one of my favorites.  Their showy white blooms are stunning in early summer, but the heart shaped dark green foliage keep this climber looking attractive all summer long.  To get best results you will have to amend the soil by adding lots of organic matter, compost and triple-mix, to aid in moisture retention, and providing the nutrition that these plants need.  Another climber tolerant of shade is a climbing euonymus (E.fortunei) .  This plant does not produce any significant flowers, but the variegated form will brighten up a dark corner.  Euonymus are not too fussy, so a minimum amount of soil amending is needed.  In both cases, patience is required!  To assist with your “need for speed” you might consider planting an annual climber along with one (or both) of these recommendations.  Canary vine is a fast grower that can tolerate some shade.  You may not get many flowers, but you will get fast coverage.

You might also consider these  easy care shrubs: Witch Hazel (Hamamelis virginiana) is a lovely shrub which can grow 8 to 25′ and offers attractive fall colour and winter interest in a shady location.  Nannyberry (Viburnum lentago) is another very adaptable shrub growing 5 to 8 feet.  It produces showy white flowers, followed by fruit – extremely attractive to birds, and finishes off with good fall colour.

I am very hesitant to suggest a bamboo for your location.  Bamboos typically are horribly invasive. We get many questions from gardeners on how to get rid of it, and the process is NOT easy.  I know that there are non-invasive types, but I have yet to see one that is well behaved.

I have attached a link to the Ontario native plant council.  It makes so much sense to plant a native. We know that it is admirably adapted to our climate, it provides food and shelter to bees, birds and other animals. And of course, it will not be a detriment to you or your surroundings  .  I wish you all the luck with your search.

https://www.ontarioinvasiveplants.ca/wp-content/uploads/2020/04/Southern-Grow-Me-Instead-1.pdf

Five Ornamental Grasses for Shade is an excellent article by Lorraine Flanigan for Garden Making, which lists hardiness zones and mature sizes of the various grasses. The University of Illinois also has an excellent list on shade tolerant ornamental grasses.