According to Wikipedia, a catenary is "the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight." In a garden, it is formed by a series of posts at regular intervals with chains or ropes hanging between them. They are sometimes referred to as swags. Climbing roses and ramblers are typically planted on the posts and trained down the chains hanging from the posts.
While this might be typical practice, I don't think it is best practice. When the growing tip of a plant is lower than the top of the top of the plant, vigor is diminished. That is the opposite effect you would want to achieve. There is a time and place for that, but not here. This scheme limits the number of roses you can grow on a catenary and doesn't capitalize on the growth habits of climbers and ramblers. It makes the use of catenaries more of a challenge for cold climate gardeners, as more of the plant is suspended high in the air.
How to create a catenary in 4 simple steps
1. Set posts firmly in the ground 10-12 feet apart. The posts should extend out of the ground 8-10 feet. I used steel army surplus posts. They were cheap, plentiful and army green in color, so they blended right in. I wish they were taller. Do not set posts in cement. Doing this is unnecessary, shortens the life of the post and does not let you plant the roses close to the post. You may use black locust, pressure treated wood or heavy steel posts. Set them 2-3 feet in the ground. There will be a lot of weight pulling on them.
2. Suspend chain or heavy rope from the top of one post to the top of the next and so on. I keep the bottom of the curve of the catenary about 2 feet off the ground. Most catenaries are made with the bottom of the curve 4-6 feet above the ground. Rope will rot over time. I used one continuous length of chain. That allowed me to play with the curve created between arches until I got it just right. I wish it was rusty and not so shiny.
3. Plant a climbing rose at the base of each post or on either side of the posts. This is an ideal position for smaller climbers or pillar type roses. Some roses tend to have a more upright form like 'Antike 89' or 'Eden.' This is the ideal spot for them. Do not try to grow those types of roses fanned out on trellises. Do not fight the nature of the plant.
4. Plant vigorous climbers or ramblers with flexible canes at the bottom of each catenary, centered between the posts. This keeps the chain close to the base of the rose. The canes are easily trained from there, covering the chains from the bottom of the curve going up and encouraging vigorous growth. As the roses grow, wind the canes around the chains in both directions.
Training roses on a catenary
Throughout the growing season, I am always winding rose canes (both basal canes and lateral branches) around the posts or the chains. The canes are most flexible when they are growing. Trying to wind a thick cane around a post or chain can result in it snapping. It takes practice, lots of practice. You will get a feel for it in your hands. This was something I learned over the past 30 years when wiring and training bonsai. You increase the flowering potential of any climber or rambler by training the canes in a more horizontal position. This is most obvious on the chains, but also occurs every time you wind a cane around a post.
Pruning roses on a catenary
I prune at least three times a year - after the first flush of flowering is over, towards the end of the fall bloom, and when the forsythia buds swell in the spring. I shorten some of the less vigorous flowering shoots to 4-6 buds. This thins out the volume of canes twined around the chains or posts and increases flowering wood. Do not cut out too much old wood on climbers. Over time, you might have to cut some old canes back that have become unproductive. When doing that, always cut just above a new side branch that is growing in the direction you'd like the plant to grow.
Ramblers require more aggessive pruning as they send out many basal shoots throughout the growing season. The old practice was to flush cut all the old wood to the base after the rambler was done blooming and wind the new wood in place. I thin out between 1/3 to 1/2 of the old wood. This approach leaves a fuller, more natural look.
In pruning and training, sometimes you have to unwind the canes from the posts and chains. Yes, it sounds like a lot of work. But it looks so good when you are done. And the more time you spend working in your rose garden, the more you will notice.
One warning - dress appropriately. I wear a heavy duty long sleeved shirt or canvas jacket. Find a pair of gloves that protect your hands, but give you freedom of movement. Sometimes, I wear a glove only on my left hand. I try to do the bulk of positioning of canes with that hand, saving my right hand for manipulating smaller shoots and holding the pruning shears. Wear a close fitting cap on your head, as well. It keeps the canes from snagging on your head or ears.
Please post questions in the comment section. For those of you who learn best by seeing, feel free to come by when I am working in my garden. For those of you who learn by doing, you can even help.
I hope to start twittering in April so you will know what I am up to in the garden as soon as it happens. I wil also be posting more frequently on Facebook as the pace picks up in spring. My wife, Renate Schmitt, and good friend, Alex Solla, (http://www.wix.com/oohmyheck/sollaphotography) will be taking lots of pictures that will be posted on upcoming galleries on the Der Rosenmeister website (http://www.wix.com/derrosenmeister/welcome, as well as on the Der Rosenmeister Facebook page.
In a future blog, I will talk more about the nuts and bolts of pruning, including what tools I recommend.