Ask Mr. Smarty Plants

Yes, you can ... BUT ... there are a number of things you need to consider before you head out with your loppers.

You will have to realize that you are committing yourself to an ongoing project.  You can alter the growth habit of a plant but it can require a lot of work (i.e. topiary, bonsai and espalier).  Some people like to call it "hortitorture" but you can achieve something more natural by using pruners and not shears.

Keep in mind that "pruning stimulates growth" and that new growth will emerge from the outermost bud that you leave.  You can direct the new growth, and shape of the shrub, by selecting which buds to leave and which to remove. Dogwoods will usually put out more than one branch at the node where you prune them.  So if you cut about a foot off a single stem that is four feet tall, the result will be a three foot stem with two or more twigs sticking out from it.  This can lead to an effect like an arm with a bunch of fingers spread out at the end, or a "witch's broom".

That means you should go easy.  Look at each of your stems (the central one is larger because it produces hormones that inhibit the growth of the others) and decide where you want to cut off each of them to create branching. You can cut some of them close to the ground or cut them off completely.  Once your plant reaches the height where you would like it to stay, you will have to cut some growth off every season. If you cut them at various lengths, it will be easier to maintain the plant's casual look.  Otherwise you will end up with a "green meatball". 

Check out this link Cornus drummondii (Roughleaf dogwood) to our database entry and look at the images of more mature plants.  You can see that they are a result of pruning off all but a couple of stems and then letting them mature.  You can imagine what the plant looked like when it was small.

My father always says "measure twice and cut once".  It's a good rule to follow when pruning plants.  Before I cut, I put my hand where the cut will be and try to visualize what the plant will look like with that part of it gone forever.  It does grow back, but not like hair! There is a great article (with illustrations) on pruning shrubs on the Purdue Extension website that you will find helpful. Also check out the numerous articles on eHow.com about Pruning Dogwoods.