Let's get vertical

Several years ago a couple of style masters in the United States created a design called the Bold Romantic Garden.

Landscape architects James van Sweden and Wolfgang Oehme used sweeps and swaths of black-eyed Susans, sedums and ornamental grasses in their designs. It was like Little House on the Prairie goes uptown. I'm not sure what was romantic about it, but it was certainly bold, the rounded-gummy bear shapes of the sedums crashed right up against the slashing verticals of the grasses.

There was a lot to be learned about shape, contrast and courage. The courage to put big plants in small spaces, and tall plants next to short ones. If there was a secondary message in the vision of Oehme and van Sweden it was "let's get vertical."

Verticals in the garden are like punctuation points. I remember a garden designed by them which had a carpet of ivy, flat as a plank, and then bolting up like Old Faithful were deftly place groups of feather reed grass Calamagrostis x acutiflora (Zone 5). It was surprising and fresh at the time, and relieved the monotony of the groundcover.

In a new garden getting big verticals, with lots of elevation, as they say in the ski industry, requires patience, money or creativity. We long for the beauty of sturdy arbors, sheltered benches or big trees. Nothing says vertical like a ramrod straight shagbark hickory or Kentucky coffee tree, but those long lasting beauties are rarely part of the planting plan in new gardens. New trees in new gardens are usually small and slow growing, barely big enough to support a swing or even a piñata. The magic combination of fast growing and desirable rarely combine in trees. Willows and poplars, often used to reclaim pasture land, are vigorous growers, some of them up to eight feet a year but they are short lived, water hogs that drop a lot of refuse. In parks, or on big properties they can find a suitable home, but in most gardens they are bullies.

The list of good, fast growing trees is a short one, There does seem to be a consensus though that the red maple, Acer rubrum (Zone 3) belongs on the list.

The U.S. Department of Agriculture calls the red maple a "supergeneralist", growing in the widest variety of sites and conditions of any tree in North America. Pretty, fast growing, loved by birds, good fall colour, the red maple has an impressive resume. On the minus side the bark can be bothered by sunscald and branching may be weak.

Joining the red maple as fast growing but good trees are the ashes Fraxinus (Zone 3) and honey locusts Glenditsia (Zone 4). The locusts produce a delectable filtered shade - and the ashes just lurk in the background, straight trunks, green leaves, solid citizens.

So go ahead and plant trees, nurture trees and while you wait patiently for a vertical epiphany, plant something for instant gratification, like the giant reed grass, or Arundo donax. This Zone 6 grass can grow 14 feet (4.2 m) in a single season. It is native to the Mediterranean and has been used to make reeds for woodwind instruments for over 5,000 years. I saw it recently, looking exotic and suggestive in a bed of ornamental grasses at the Royal Botanical Gardens in Burlington. Use it to screen off homely views in the garden, or as a glorious, robust specimen plant. Giant reed tolerates moist or dry conditions and luckily dies to the ground in cold climates, unlike California where it has become a vigorous and unwanted invader of moist areas. In his excellent book, The Color Encyclopedia of Ornamental Grasses, Rick Darke recommends using giant reed for a stunning vertical accent in containers.

For a more cold tolerant group of grasses that still have great vertical presence, consider miscanthus (zone 5). Some types will grow up to 10 feet with grace and style. Most miscanthus form distinct clumps, but beware of the running types that spread underground by rhizomes. There's one named 'Interstate 95' and that provides a big clue to its aggressive nature.

When our garden was young I longed for tall as a beanpole plants that would break up the predictable pattern of shrimp sized perennials. I relied on the grasses to do this, and plunked in tall rangy sunflowers to stir things up, as well as willowy patches of flowering tobacco.

Tall wooden structures help too. At Bryce Weylie's Celtic garden in Vinemount, Ontario, called Ferris Lane, the flat landscape is reshaped by rugged, wooden obelisks, pergolas, and oversized benches. The magical pieces look like they could spring to life and start growing again. It's clear that no expensive woodworking tools were used in their creation, just hunks of wood, nails and some big biceps to hammer them together. People seem bewitched by these fairy tale objects and cart them home to transform their gardens with a bit of whimsy and a splash of the vertical.

So research your trees, be bold with the grasses and tap into creativity. Just now I am thinking, what about propping up a nicely weathered old wooden ladder- and planting golden hops at its base. There you have created your own stairway to heaven.