What Is a Ha-Ha?

One key decision to make in garden design is how to deal with the boundaries of a property. Should you opt for a wall, a fence, or a hedge? Or is something a little out of the ordinary like a "ha-ha" a solution that might work?

What Exactly Is a Ha-Ha?

A ha-ha is a very old idea, which goes by a lot of different names. It is also known as a ha-haw, a sunken fence, a deer wall, or a fosse, for example.

But whatever it is called, this concept is a relatively simple one, and refers to a landscape design element which includes a dip in the ground, with a slope to one side, and a vertical structure such as a wall or fence on the other.

A ha-ha gives the protection of a typical wall or fence, but, since this structure is sunken into the ground rather than protruding above it, it gives unobstructed views from the boundary of a property.

The name ha-ha is said to come from the element of surprise that such a feature gives to one who comes across them. Since the boundary is hidden from sight until you come up close, people would make an exclamation of surprise, "Ha ha!" or "Ah-ah," when encountering them. 

The name is believed to be French in origin, but similar sunken ditches were a feature of ancient origin; they were commonly used in deer parks in England to allow deer to leap into an area but which would not allow them to leave.

Later, these became features of landscape gardens on great estates, where they would keep livestock contained and out of formal gardens while not obscuring sweeping views.

The concept spread from Europe to North America, too. Mount Vernon incorporates them on its grounds as part of the landscaping for the mansion built by George Washington's father.

Where a Ha-Ha Could Be Helpful

Ha-ha designs are most often associated with grand estates and other expansive properties. But those looking for sustainable solutions could find them useful within smaller domestic designs, too. 

One of the challenges when choosing how to create a boundary for your property could be finding a solution which provides a degree of protection without obscuring views. If you have a pleasing outlook, the last thing that you will want to do is create a hard barrier which restricts your sight lines. 

For example, in a recent design of mine, I had a client who had a property looking out over a wooded valley and needed a barrier to keep livestock contained, but who did not want to spoil the views from their home. A ha-ha provided the solution.

It can also help keep out deer or other wildlife where these are a problem for food cultivation. Many gardeners who live in areas where there are a lot of deer present will install tall fences around a vegetable garden or orchard area. A ha-ha can potentially provide the same level of protection without tall and unsightly structures marring the views.

Another thing to think about is that digging down to create one of these sunken features can—at least where the wall faces in the right direction—provide opportunities to create earth-sheltered structures like root cellars or sunken greenhouses. In the design mentioned above, for example, the vertical wall of the ha-ha faced south and was used as the location for an earth-sheltered greenhouse as part of the design.

Ha-has can be extremely practical as well as aesthetic features in a landscape design. Of course, the specific design for such a feature depends on the site's characteristics. While they can be somewhat time-consuming and perhaps more costly than other options to create in the first place, they should, when properly planned, be able to solve problems neatly and stand the test of time.

These will not be a solution for every site. You will need to think about the properties of the soil, hydrology, the costs of materials for the vertical wall, and the costs of creating such a feature. But when carefully planned, a ha-ha is no joke. It could be an interesting age-old solution to consider.