Enter the book “Planting Green Roofs and Living Walls” By Nigel Dunnet and Noel Kingsbury.  Some good ole boys from Germany who love to talk about vines and roof grass.   Who would have thought there are German Hippies?  Well, it takes a German Hippy to figure this stuff out.  The book is first part – roofs, second part heavy vines.  Most references in the book are related to Wisteria,which is why it works so well.

Google has portions of the book online, here: “Planting Green Roofs and Living Walls”

So let’s get to the data.  Firstly, a chart right out of the back page:

Wisteria Data

• Size: 30 m – 99 feet (difficult to get them to grow horizontally).
• Profile: max of 1.2m – 4feet
• Zone: 5
• Vigour: Very strong
• Weight: light, maximum of 15kg (about 25 pounds) per square meter (1.4 pounds per sq foot).  Although this may be exceeded by weight of trunk at lower levels, which carries much of its own weight.
• Support: vertical supports, round cross section, trellis with right angle mesh.
• Min Height of support: 15 meters
• Optimum width of support: 3m – 9.9 feet
• Distance from Wall: at least 15 cm with the possibility of a sizeable trunk developping in later years at the base. (Up to 1.5 feet thick)

Notes: “Supports need to be of a material whose surface roughness will eliminate the possibility of the plant’s wt causing it to slip.  Steel cable and fibreglass both offer enough surface friction.  … In some cases, vertical cables are actually designed to break at high tension.  the plants are held at the top and firmly rooted at the base, so this does not matter.”

Wall Support Types:

Great page right out of the Book:

Trellis Diagram

Material for Trellis

Their recommending Metal, because it doesn’t fall apart after 25 years like wood.  But these guys are engineers, so you expect them to push “common Sense”.  In my case, I prefer wood as it is so much more beautiful and alive.  Regardless, they make the great point that industrial steel cables are meant for this type of work, are easily available and do a good job.

I love Wisteria’s.  They look amazing and smell fragrant.  I want to grow one up the South side of my House (which is currently quite barren) (See photos below).

View at Picasa

View at Picasa

The South side of my house receives plenty of sun, which is a requirement for the Wisteria.  The one drawback is that my south side receives wind as it is open to the street.  My neighbors will be the lucky ones, as they will have a full view of the shrub it’s entire bloom time.

Wisteria Blue Moon

But there are issues.  Several in fact.

1. Wisteria are incredibly invasive, killing trees and destroying walls.  The general understanding is that they need very strong (the strongest of the vine plants) supports.  For some reason, and this is strange, I’m having trouble finding information on “strong supports” for Wisteria.  This is the limited information that I could find:

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Books on Hanging Wisteria up a wall

1. Ultimate Guide to Fences, Arbors & Trellises: Plan, Design, Build

Looks Promising

Fences, Arbors and Trellises

2. Planting Green Roofs and Living Walls

Looks the most promising of the lot.  Specifically devotes several pages to the Wisteria and the challenges (ie. the sheer weight) in growing it up the side of a building.

Wisteria Plant Blue Moon

3. Northeast Home Landscaping: including Southeast Canada

Northeast Home Landscaping: Including Southeast Canada

Details about Wisteria

This website has amazing information about Wisteria’s growing in Ontario / Zone 5:

1. http://forums.gardenweb.com/forums/load/grtlks/msg0810315814807.html

2. http://ohioline.osu.edu/hyg-fact/1000/1246.html

Recommended Wisteria:

The general consensus is that America Wisteria are more controlled and will bloom in Zone 4/5.  Whereas Chinese/Japanese Wisteria smell great, but can grow rampantly and out of control.  If you have a controlled area, best to go with the American varieties.

The hardiest wisteria, so far, is Wisteria ‘Blue Moon’ introduced by Rice Creek Gardens in Blaine, MN. ‘Blue Moon’ is hardier than ‘Aunt Dee’.

American Cultivars:

1. ‘Blue Moon’
2. Aunty Dee Wisteria – (wisteria_macrostachys)
3. Wilkerson Mill’s American wisteria
4. Kentucky wisteria
5. “Lawrence” Wisteria – Starts blooming right away. Recommended by the Royal Botanical Gardens in Burlington.

Great advice on growing a Wisteria:

http://www.canadiangardening.com/how-to/techniques/make-your-wisteria-bloom/a/1541

The subject of wisteria is fraught with frustration for many Canadian gardeners. There are plenty of arbors and pergolas festooned with healthy-looking wisterias that simply refuse to bloom.

So what’s the secret to getting the magnificent show of fragrant blossoms that are on view each spring at Royal Botanical Gardens in Burlington, Ontario? Gardener Bob May says there’s not much to it: don’t let your wisteria grow out of control and give it two good pruning’s a year-once in midsummer and the other in mid-September, or when vigorous growth has ceased.

Every three years or so, your wisteria will need a radical renewal pruning to keep it in shape. Wisteria responds best to stress. Be sparing with fertilizer and wary of high-nitrogen formulas, which will result in too much vigorous growth and foliage. And don’t overwater. The phenomenally healthy wisterias that strut their stuff on RBG’s pergola pretty much look after themselves and only get watered during extreme drought.

What’s the most floriferous wisteria on the RBG pergola? It’s ‘Lawrence’ Japanese wisteria (Wisteria floribunda ‘Lawrence’, Zone 5).

Wisteria primer – It’s easy when you know how

1 After flowering is finished, prune entire plant back, thinning it out well and leaving just one or two buds or nodes per branch. Keep vigorous, strong shoots that have set buds or nodes at their bases. Get rid of any branches that hang down and spoil the shape of the plant. To force the plant to branch more horizontally, make your cuts on a down-facing bud (even if you cut below this bud you will get new branches).

2 By midsummer, wisterias have put on a great deal of new growth that can tangle into a big, shapeless blob, encroach on nearby plants or weigh down supports. Don’t be timid with the pruners: prune entire plant back hard to the desired size and shape and cut thin, overcrowded stems out completely. By summer’s end, new shoots will appear and replace most of what’s been cut off. This is the time to select vigorous new shoots for training along wires, a trellis or even up a tree.

3 In mid-September (or when vigorous growth has ceased), cut wisteria back again, though not as ruthlessly, to its desired shape for the following spring. This time, leave four or five nodes or buds per branch; these will form next year’s flowers and branches. If you see something resembling a witch’s broom at the ends of the branches (several short, dense shoots clustered together), don’t remove it all-it’s full of buds, so just shape carefully and thin out weaker stems and dead tips (about one-third in total). Cut back any split panicles (flower heads) and seed pods so they don’t rob energy from flower production.

4 Wisterias usually bloom on the lower 30 centimeters or so of last year’s stems. By pruning these back several times a season, a flowering, multi-branched stem-much like an apple spur-can be created. Every three years or so, when these stems have grown out too far from the main structural stem, give the plant a renewal pruning right after flowering, severely cutting back mature wood to within 7.5 centimeters of the main stem. This will open up the plant and allow in light to help stimulate new growth.

Support Data:

Wisterias climb best on wires, trellises, arbors and pergolas. They can be grown on solid, vertical surfaces if proper supports are provided, such as rows of wire attached four to six inches from the wall. Use sturdy, durable materials such as galvanized wire, tubing or wood. Copper or aluminum wire or tubing are preferred over other metals since these do not rust.

Good book on Wisteria:

Wisterias: A Comprehensive Guide

Wisterias: A Comprehensive Guide