Climbing Plants - Greening Vertical Spaces

The vertical spaces in a landscape are often ignored, but when you walk into a garden that has used climbing plants wisely, another dimension is added that is often breathtakingly beautiful,  that lifts they eye and heart 'upwards' and 'over' instead of just 'along'.

Pyrostegia venusta - used in my neighbours' garden to cover an ugly fence and create a self-supporting archway.  This is a good climber to use if you want a plant that is green from the ground up - often climbers have bare stems at ground level.  Beware - this plant is very vigorous and needs diligent maintenance.

One modern incarnation of vertical landscaping is the increasing popularity of green walls in our cities and urban spaces -  where architects are beginning to realise not only the environmental benefits of greening whole buildings, including roof spaces, but also the beneficial impact of their visual beauty.

Gardens of the Acropolis Museum, Athens.  This otherwise ugly wall in the background building formed part of the boundary of new Museum gardens - what to do with something like this sticking out like a sore thumb - green it.

Climbing Plants for the Home Garden

Success with climbing plants comes with an understanding of how they climb - do they twine, do they have tendrils or suckers, do they scramble and have thorns, and then matching the right plant with the correct structure for them to climb over  - this is your key to success.  

Epiphytic orchids (they don't need soil!) used to create an arbour - to stunning effect - in the Singapore Botanic Gardens.  Who would have thought to use orchids in this way? (You could do the same with small bromeliads - they are also epiphytic)

For example.  Plants with tendrils; Passiflora sp. (Passion flower and fruit), Pyrostegia venusta (Orange trumpet creeper) and everything in the climbing peas won't grow just up a pole - their tendrils need something to cling onto.  Conversely, plants that like to twine need a pole to climb up and won't be very happy with a piece of mesh, these include: Wistaria sinensis (Wisteria) Vigna carracalla (Snail Vine) and Trachelospermum jasminoides (Star jasmine).  Then we have the scramblers - often with thorns - these need a wall or arbour to climb over or against and constant attention to keep them in check e.g. climbing roses and bougainvillea.  So, one size does not fit all!

Three different ways I have used climbers in my garden:

Passionfruit (Passiflora edulis).These are climbing plants with tendrils that need support to cling on to.  I needed something to reduce the amount of sunlight coming into my bedroom and in our outdoor dining area, which is next to it.  I chose Passionfruit because; it has tendrils so I could train it to go exactly where I wanted it to, a clear trunk at the bottom that would not impact on the rest of the garden bed, it has lovely glossy green foliage, beautiful flowers and the added bonus of delicious fruit.  I simply tacked some plastic lattice to the underside of the eaves where I wanted the vine to grow - the tendrils did the rest!

Snail Vine (Vigna carracalla) . This is a twining plant - like every climber in the bean family.  What I needed for this job was a plant that would twine itself over an arbour that leads down to the lower part of the garden.  I wanted something that was really beautiful, preferably with a fragrance, because this is a focal point in the garden, and not too vigorous - i.e. something I could control because the frame of the archway is quite small.  This is where deciduous climbers come into their own.  Because they loose their leaves in winter they give a seasonal shape to the garden and also makes them easy to prune to the desired shape.  PS this plant has the most gorgeous fragrance and the stunning flowers really do look like little snails.

Use of deciduous plants -  lightbulb moment: I actually really got switched on to the joy of gardening when I was sitting in a class, right at the beginning of my horticultural studies, and we were exploring the use of all kinds of deciduous plants and realised that you could use plants, not only for their beauty, but for passive light and heat control.  Think of a beautiful wisteria vine over a pergola in summer providing a cool, shaded and scented place to sit, and then in winter allowing the light and heat of the winter sun to penetrate through its bare stems.

Bougainvillea: These are scramblers with arching canes and hooked thorns - they need support.  I have a brick pathway that leads to the back of the house so I wanted to create a beautiful entranceway that lead they eye to the back garden, and something that I could  train with horizontal supporting wires, keep flat against the wall and that wouldn't impede the path.  (This is the garden art of espaliering - often used to train trees and shrubs flat against the side of a building or as a living fence).

It was also facing west so keeps pretty hot and perfect for a bougainvillea - flowering for most of the year - and I could have my favourite Scarlet O'Hara.

To maintain it I just have to cut off any stems that are poking out at right angles over the path, and any that are climbing onto the roof.

To encourage repeat flowering: give a light prune after flowering; feed and water then but do not OVER WATER and FEED while it is in flower otherwise it will just put on a lot of foliage at the expense of the flowers. 

Because of their stunning flowers most people would dearly love to have a bougainvillea in their garden, but can I give you a few tips about where to plant them that I have learned from experience?

• Only plant bougainvillea against a support.  DO NOT PLANT IT IN A SHRUB BORDER - because, before you know where you are, you will have a thirty foot thorned giant that nobody will want to deal with.  My son is an arborist and, from experience, refuses to take these monsters out for people who have randomly planted them and then regretted it.  We have both had nasty THORN experience!
• Plant only in an OPEN, SUNNY position against a wall/fence that gets the hot afternoon sun otherwise THEY WILL NOT FLOWER
• As with all climbers - PRUNE to shape right from the BEGINNING because it's hard to correct this once it is mature.

Bougainvillea make fantastic POT PLANTS and seem to thrive on being a little pot bound.  If you have ever been to Bali you will know what I mean because they have been used to stunning effect along the roads around the main airport.  They also graft really well and you can end up with an impressive specimen with several varieties on the same plant!

I wonder which came first - the door or the bougainvillea?

GREENING VERTICAL SPACES - How to choose the right plant?

Case Study - Jo and Justin's wall?

The Clients:  My young friends Jo and Justin have recently moved into an inner city terrace in Sydney, gutted the whole place and been renovating - no easy task with three children under five!  This is their tiny, narrow back yard dominated by a rear brick wall and bordered by a path that provides access to a side lane-way on the right.  It has good light - facing north-west.

They have already started to tackle the garden, laid some grass and put in a raised veggie bed and eventually they want to 'green the wall' - but at the moment it is being used for other purposes!  It's not an urgent job so they have plenty of important time to THINK about it.

What are the Constraints?

• It has to be beautiful because it is the focal point of the whole house and garden.
• Anything planted cannot grow out too far otherwise access along the back pathway will be compromised.
• Cannot use anything not 'child friendly' i.e. noxious, allergenic or have thorns.
• Preferably a useful plant (edible?) to maximise the limited space.
• Must be suitable for their climatic zone (warm temperate/sub-tropical) - no square pegs in round holes please!

What are the Choices?

1.  Well, if you never wanted to paint the wall again you could use ivy - which has suckers along the stem that adhere themselves to the brickwork - that way you would not have to erect a support frame or wires. 

It is also a very hardy plant tolerating neglect however,  as you can see from this picture, it is not entirely maintenance-free and would require regular pruning to keep it flush against the wall.

Ivy (Hedera sp.) comes in variegations and different shades of green.

2.  Using espaliered citrus trees - thorn-free varieties - and maybe one for each of the children?  Plant selection is a matter of personal choice, but I would probably chose citrus varieties with smaller leaves (to give a denser cover) and definitely ones you are going to use e.g. lemon, lime, mandarin, kaffir lime, calamondin and cumquat.

These will require regular feeding and maintenance, but I think the rewards of creating a beautiful wall that is wonderfully fragrant in the springtime and provides an abundance of fruit might just outweigh that?

For a uniform effect the same species would have to be used (as in the lemon trees above), but you could use different kinds of citrus, just making sure that you planted the tallest in the middle.





3.  Star jasmine (Trachelospermum jasminoides) is a firm favourite with year round glossy, green leaves and a fantastic display of fragrant star-like flowers in the springtime.  This is a very hardy plant, tolerant of city pollution and easy to shape.

The stunning effect in the photo is easily achieved by stringing stainless steel wires from the ground up, to whatever height you want, then placing an individual plant at the bottom of every wire.

Of course it will need trimming and training to shape, but I know that Jo and Justin have a ladder!





4.  My last suggestion suitable for this situation is the fabulous Magnolia grandiflora - like the citrus suggestion these are not, in fact climbers, but can be used to grow flush against the side of a building again with espaliering techniques.  They have been used to stunning effect like this in European gardens for centuries and you will see them everywhere in the warmer Mediterranean countries greening the walls of glorious old buildings.

Again with glossy evergreen leaves, rusty coloured on the underside, they produce beautiful saucer-like, fragrant flowers with a heady citrus/gardenia perfume.

Certainly using a plant like this will require maintenance, but that is the case for whatever you chose.  Gardening is not like interior decorating - it is not 'finished' when it is finished!






Greening Vertical Spaces  - a summary. Choose the right plant and support for the situation (not the one that took your fancy at Bunnings!)