Keep Vine Roots Away from Walls!

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Plant the roots of climbing plants well away from drying walls. Source: Claire Tourigny, from the book Les 1500 trucs du jardinier paresseux

Whether you let them cling directly to the wall or have them climbing up a trellis attached to the wall, growing climbing plants on your house creates a charming effect.

The problem is that, if there is one place where the roots of climbing plants are unhappy, it’s in contact with the building’s foundation. This is usually the driest spot in your entire yard, as they’ll find themselves in the rain shadow caused by the eaves above, and this means very little precipitation reaches the ground. Also, the foundation gives off heat, drying out the soil at the base of the wall even further. In addition, the average foundation is made of concrete, a very alkaline product that leaches into the adjacent soil, yet most climbers prefer their soil slightly acid or at worst, no more than neutral.

Fortunately, it’s easy to grow climbers in such a way that they can work their way up your wall without their roots being in the foundation’s dead zone. Just plant them at a distance from the wall, in the area beyond the eaves that receives normal rainfall, and then direct the stems towards the wall they are to climb.

To do this, plant the plant at an angle, almost horizontally, with the root ball pointing away from the wall. That way the roots will be located in rain-rich, less alkaline soil while the branches will automatically be oriented towards their future support. Easy peasy!

Twining Plants Like ‘Em Thin

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Twining stem

Most climbing plants cling to their support by twining, that is wrapping themselves around it. And most twining plants will readily climb fairly thin supports, but can’t always twine around a thick pole, a tree trunk or even the fairly wide bars of many trellises.

Most vines with twining stems, such as morning glories and pole beans, prefer supports that are no more than 1 1/2 inches (4 cm) in diameter.

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Tendril

As for vines that climb by means of tendrils (specialized threadlike stems that twist like a corkscrew), such as peas, grapes and clematis, most are even less capable of clinging to thick supports: 1/4 inch (5 mm) is about the widest they can handle.

In spite of this obvious need for thin supports, many if not most commercial supports for climbing plants (trellises, obelisks, pergolas, etc.), although in theory designed for vines, are simply too thick for them to cling to, forcing the gardener to attach them to their support by other means, with clips, twist ties or pieces of old panty hose. This is easy enough to correct: just fix metal or plastic mesh (like garden netting or bird netting) to the support. Vines will climb netting with no difficulty. Or simply run a taut cord or wire from the ground to top of support so they can wrap around that.

But why should you have to work at fixing a design flaw in a commercial product? Just make your life easier by choosing an appropriate support from the start: one with poles or bars that are thin enough for vines to wrap around them all on their own. Bring your measuring tape next time you shop for a trellis: think  1 1/2 inches (4 cm) for twiners and 1/4 inch (5 mm) for tendril climbers.

In gardening as it any project, you’ll always have less work to do when you use the right tool!