Why do they tie strings around bushes in the winter?

So they won't go south for the winter!

My guess is so snow does not stack up on branches and cause them to snap?

Lol!

Hm. Not sure, Elsa. The way the strings are tied, it doesn't seem that way. I should have taken a picture.

Elsa is right, the weight of snow can bend the branches low and they snap off, or the bush gets very misshapen. I've a hebe by the side of my front door and it's looking very sorry for itself after the last few days!

It's best, if you can, to bang shrubs with a broom handle to get the snow off when it settles

ETA, can you describe what it looked like Caroline?

Prevents wind damage and the winter cold.

It might just be to ensure they grow in a certain way - you can train trees and shrubs to a shape, while they are young and the wood is still soft

ETA yes it might also be to avoid what's called 'wind whip'. People often do this with big rose bushes

It just looked like a string or two tied around the edges of the bushes. It didn't look like they were holding anything together, or like this would protect them from snow. I don't know. I will try to take a photo tomorrow. I drive by them everyday and the curiosity has finally driven me to ask what this is all about.

Maybe they are a marker for where to trim in the spring.

As an apology:

From:

http://www.extension.umn.edu/distribution/horticulture/dg1411.html

 Snow and Ice Damage

Heavy snow and ice storms cause damage by bending and breaking branches. Multiple leader, upright evergreens, such as arborvitae and juniper, and multiple leader or clump trees, such as birch, are most subject to snow and ice damage. Relatively small trees can be wrapped together or the leaders tied with strips of carpet, strong cloth or nylon stockings two-thirds of the way above the weak crotches (Figure 3). These wrappings must be removed in spring to prevent girdling, and to allow free movement of the stem. Proper pruning, to eliminate multiple leaders and weak branch attachments, will reduce snow and ice damage. For trees with large wide-spreading leaders or large multi-stemmed trees, the main branches should be cabled together by a professional arborist.

Figure 3. Protecting trees from snow or ice damage.