Growing Vertical

Create a curtain, accentuate an archway or terrace a trellis—all with flowing, growing texture.

Say you’ve downsized from a home with a sprawling yard and lush garden to an apartment with a balcony. Maybe you want to create a screen where you can relax and enjoy your garden in private at day’s end. Or perhaps you find bending down to tend a ground-level garden difficult. The simple answer: grow vertical.

Vertical plantings provide structure in a garden, offer shade and wind protection and can disguise an unsightly view. The flowers of many climbing species offer food for hummingbirds and butterflies. For the kitchen gardener, growing crops vertically means a more efficient use of the garden bed, better air circulation around plants, and better crop yields given there’s less spoilage on the ground. And a vertical garden doesn’t just mean plants that climb up—it can mean plants that hang down or trail, from a planter box, window box or hanging basket. By planting in some form of container or raised bed, you can help to stay vertical yourself.

Plants are remarkably clever, evolutionarily speaking. Many have developed specialized structures to help them cling to supports, or have evolved particular ways of growing otherwise that allow them to stretch skyward. Others are content to scramble through the branches and stems of neighbouring plants.

How Climbers Climb

One type of evolved structure is the tendril, a modified stem or leaf that curls around something it can grab, holding the stem of the climber in place. (A common example of a plant with leaf tendrils is the sweet pea.) Plants with tendrils are easy to train on any support, although if you’re growing something heavy like a grapevine, you should have a sturdy support for the tendrils to grasp.

Other climbing plants have twining leaves and stems that wrap around string, wire, slender poles and other supports. The young leaves of clematis twist very easily around anything they come in contact with, and can just as easily twine themselves into a tangled mess unless they are given some training. Twining stems are found on morning glories, pole beans, honeysuckles and bittersweet vine, among others; depending on the species, their stems twist around structures either clockwise or counterclockwise.

Ivies such as Boston ivy and Virginia creeper have clever adhesive pads on their stem tendrils, allowing them to attach to just about any surface. It doesn’t matter to these plants whether they grow up or down or sideways; wherever they find a spot to anchor, they’ll stretch out and make themselves at home. Other ivies such as English ivy, climbing euonymus and climbing hydrangea have adventitious stem roots, roots that sprout along stems and hold tightly to most any surface.

Both of these types of climbers can be hard on masonry and paintwork—if you’re concerned about damage to a chimney or a wall, avoid planting them where they can climb on your house or other buildings.

Although we refer to them as climbers, plants such as climbing roses and bougainvillea are actually scramblers. They have long, flexible stems that clamber through other shrubs and trees.

If left without any structure to support them, climbing roses will still grow happily, but will form a more mound-like, sprawling growth.

Supporting Acts for Climbers

Although climbing plants have their own means of holding on to supports, sometimes they need a little direction—or help. There are many types of plant ties and twines on the market, but one of the most useful I’ve found is Velcro plant tie, available in a nine-metre roll. It’s perfect for supporting most plants and can be used over and over again.

There are wonderful handmade structures to be found at craft shops and flea markets, or even just offered for sale in someone’s front yard. You can find simple metal or bamboo rods at garden centres, or opt for more ornate, prefabricated wooden or metal arches, obelisks, trellises and stakes. 

When planning to take your garden to new heights, take into consideration how tall (and wide) a particular plant will be at maturity. Is it a slow-growing, well-behaved variety like a honeysuckle or a more rampant scrambler such as a bittersweet vine? Can it be grown in a container or is it best suited for an in-ground planting? What’s available to support it?

Plants to create hierarchy in the garden

Choosing plants for a garden is always the fun part. Indulge in easy-care annuals that do their thing and in fall can be brought inside or consigned to the compost heap, or perennials that erupt into great displays of colour during certain times of the gardening year.

Many perennial climbers have a particular trait that endears them to some gardeners while driving others to exasperation—a vigorous growth habit. When choosing perennials, make sure to ask about their rate of growth and spread.

Enchanting annuals

Black-eyed Susan Vine (Thunbergia alata). It loves to twine itself up any available support. If planted in a container, it can be brought in at summer’s end and enjoyed as a houseplant.

Morning Glory (Ipomoea species). These certainly are glories, although I wish they’d start blooming earlier than they do in my garden. For best results, don’t plant them in too rich soil, or you’ll have great vegetative growth but few flowers. Try such popular varieties as ‘Heavenly Blue’ and ‘Pearly Gates.’

Nasturtium(Tropaeolum majus). Flowers are magnets for hummingbirds and butterflies. As well as vibrant reds, oranges and yellows, blooms come in many subtle shades now, and plant size can range from dwarf creepers to magnificent giants. 

Purple Bell Vine (Rhodochiton atrosanguineus). The sight of this plant in bloom at a nursery stopped me dead in my tracks four years ago. I happily paid a premium price for it that year, and have enjoyed it every year since. (It’s easier to find now—cheaper, too.) I’ve grown it both trained up a small bamboo trellis and trailing down from a container. Its dramatic purple bells are eye-catching and unusual.

Sweet Pea (Lathyrus odoratus). One of the quintessential cottage plants, sweet peas look wonderful whether they’re scrambling up a piece of netting or chicken wire, or happily twining themselves around a trellis or arbour. To me the most desirable varieties are those that smell the sweetest, but of course the sweetest fragrance is always a matter of opinion.

Sweet Potato Vine (Ipomoea batatus). Most popularly used in hanging baskets, sweet potato vine is available in several foliage colour combinations, including tricolour, deep purple and acid green.

Punchy perennials

Bittersweet (Celastrus scandens). I happen to love this plant, but I have plenty of room for it to stretch its lanky limbs, and it isn’t near enough to any trees to attempt to take them over. In a small space it can be overwhelming. For fall foliage colour to spectacular and interesting fruit, the bittersweet is hard to beat. You need both male and female plants to produce berries, which are attractive to birds. 

Climbing Fruit We’re all somewhat familiar with climbing peas and beans (remember Jack and his beanstalk?), cucumbers and indeterminate cultivars of tomatoes. But some species of fruit, including apples, peaches, pears, cherries and high-bush blueberries, can be trained on special supports so they grow more vertically than bushy. Such plants can also be used as supports for other climbers. 

Climbing Hydrangea (Hydrangea anomala ssp petiolaris). This lovely plant is slow to establish but looks spectacular in late spring, when it’s covered in lacy white flowers.

Hardy Kiwi(Actinidia kolomikta). I’ve seen hardy kiwi grown with great success around the Atlantic Provinces, including the NB Botanical Gardens in Edmundston. Its appeal is the heart-shaped leaves tipped in rosy pink and cream, the colours of which are almost radiant in early summer when plants are growing in full sun. In order to produce fruit, you need both male and female plants, and while the fruit are small (about the size of a grape), they are delicious.

Honeysuckle(Lonicera species). Climbing honeysuckle tends to be a prolific bloomer that boasts lovely clusters of open, fragrant flowers, much loved by hummingbirds. It usually prefers a sunny location, and moist soil.

Hops(Humulus lupulus). Traditionally, hops were grown on farms and homesteads—housewives used them to help raise bread, and of course husbands used them for other things. In late summer, female plants produce clusters of green, papery “cones,” which have a pleasant fragrance. Some people use them in potpourri mixes or for sachets to aid sleep. Vines grow enthusiastically so are best used in an area where you have plenty of room, and aren’t trying to nurture some exotic, delicate climber. The golden variety, ‘Aureus’, with gorgeous gold foliage, is less overwhelming.

IviesFrom English ivy to Boston ivy and Virginia creeper, ivies are grown for their attractive foliage. Virginia creeper (Parthenocissus quinquefolia) will reward you with remarkable fall colour. Boston ivy (P. tricuspidata) also gives terrific fall colour, and it works well as a quick cover on walls.

Roses The secret to growing good climbers, as with growing any rose, is to buy the best stock you can find, whether from a reputable local nursery or by mail-order. Some delightful climbers include ‘Alchemist,’ ‘William Booth,’ ‘Veilchenblau’ and ‘Robusta.’ Bear in mind that these are actually scramblers and will need to be supported in order for them to grow upwards.

Silver Lace Vine(Fallopia aubertii). Much loved by some gardeners, this plant also goes by the name Mile-a-Minute Vine and is a member of the Polygonum family, which has a number of notoriously invasive species. Be wary if you have a small space.

Clematis: Stars of the Climbing Garden

Clematis is perhaps the most spectacular of flowering climbers. There are a number of different species and hundreds of hybrids with star-shaped flowers in every conceivable colour, including some with stripes and ruffles in contrasting colours. They range in size from the dainty spring blooming C. alpine, to the faithful standard C. jackmanii to some of the most remarkable, huge-flowered late-season hybrids.

The secret to growing clematis is to remember that they like cool feet and warm heads. Plant them in a sunny location in rich, well-draining loam, then mulch their roots well with straw, leaf mould or other organic matter.

People say that, although they love clematis, they're not sure when or how much to prune them. Most horticulturists say the easiest way to determine when to prune is based on when the plant flowers.

Group A clematis flower in the early to mid spring, on stems that grew the previous year. These require minimal pruning after they flower for cosmetic purposes only, if you want to neaten their shape.

Group B comprise the early, large-flowered form, which flower through to midsummer (depending on your hardiness zone) on last year's stems. In early spring, before active growth has commenced, you can prune back moderately to just above a pair of healthy buds, but don't prune too heavily or your flower production will be limited. On well-established plants, removing several stems will encourage stronger growth in the remaining stems while encouraging new shoot development, as well.

Group C are the late flowering species and hybrids, which flower on the new season's growth. These can be pruned back hard in spring, cutting each stem back to just above the first strong set of buds above the ground. On our late flowering species, the first buds appear about 20 centimetres above the soil level-once they've been pruned, they explode into happy growth and produce many flowers.