Landscape Design for ADUs

ADU landscaping is a fairly new area of landscape design specialization.

Visiting hundreds of ADUs over the last decade, I’ve observed that site landscaping hasn’t lived up to its potential. I know that for my own ADU projects, landscaping has taken a back seat to all other ADU design considerations. Developing an ADU is already a huge undertaking. Why would you also want to consider overhauling the property’s landscape at the same time? Perhaps the inattention to landscaping is due to lack of a landscaping budget, or perhaps it’s a simple oversight on the part of the homeowner or designer.  

While small space design almost has a dedicated language that has been formed for the design of liveaboard boats, tiny houses on wheels, apartments, and ADUs, good principles for ADU landscape design simply haven’t been codified yet.

Indeed, ADUs present a subtle but entirely new type of social relationship opportunity for the tenants and owners. The relationship between the occupants of the house and ADU are typically not as intimate as the relationship of housemates, but typically are closer than relationship of a typical neighbor.

Some properties with ADUs are family compounds, but more commonly, one unit or the other is designed for a totally independent household. Parts of the yard, driveway, gardens, patio, and storage may be shared, and other parts may serve as dedicated spaces for one unit or the other. Landscaping has the potential to give visual cues to the occupant and guests about the use of the property. The wishes of the property owner should inform the layout of the structures on the property and the landscaping of the remaining interstitial garden space.

Since landscaping hasn’t been given any attention yet in the vernacular of ADU design, I wanted to put together a post to focus on this topic. Recently, I visited an ADU site with a fantastic and beautifully integrated landscape, and immediately realized the potential that landscaping had to accentuate and augment the relationship of two structures on a lot. I reached out to the landscape designer and builder for this project, Joel Port of Haven Garden Design & Construction, and set up an interview to dig in to these questions further.

Kol: What are some of the principles of effective landscape design that you’ve used in ADU projects?

Joel: When designing ADU gardens, I recall a lot of the basic design principles that I learned while earning my bachelor’s degree in landscape architecture.  I also have over seventeen years of experience designing residential gardens. Many of the principles are the same, no matter the size of the site.

When it comes to space planning for an ADU project, the primary consideration is whether the garden space will be shared or separate from the main house.  That informs many of the decisions that come later in the design process.

Another objective for small space gardens is to create a sequence of events when someone comes to visit an ADU.  What type of experience do you want people to have while they’re using the garden. ADUs are often tucked away in the back of the property. There’s an opportunity from the street to set the tone as someone arrives; an entry statement.

A lot of times there should be some sort of threshold between the street and the garden. That way, as people get the property, people can say to themselves, “Ok, I’m off the street.”  They can enter the garden, and let the pressure of the day go.

That’s the principle behind the name of my company, Haven Garden Design.  I try to create sanctuaries for people to relax.

Kol: How do you factor in privacy solutions via landscape designs? How do you use fences, arbors, and courtyards?

Joel: With the Montgomerys’ project (incidentally, this ADU was designed by Propel Studios. https://www.propelstudio.com/the-wedge-adu-portland-or), the ADU bedroom and the primary house’s kitchen were directly adjacent to one another, there were sightlines to consider obviously. In this case, we used offset fence panels to obscure this sightline and provide privacy for the main house and ADU.

 Offset fence panels strategically obscure the view of the primary dwelling from the vantage of the ADU. This creates a courtyard effect for each units. As the occupant of the ADU departs toward the front of the property, the fence height steps down to create a more open sightline of both structures.  Photo by Carlos Rafael Photography-  a link to his photography website

Offset fence panels strategically obscure the view of the primary dwelling from the vantage of the ADU. This creates a courtyard effect for each units. As the occupant of the ADU departs toward the front of the property, the fence height steps down to create a more open sightline of both structures.

Photo by Carlos Rafael Photography- a link to his photography website

Usually, the limited square footage of the ADU means that you want extend the livability of that space out into the garden. A lot of times, people incorporate double doors to the outdoors. So, you want to incorporate a patio or courtyard nearby where people can lounge.

 An outdoor patio is located directly outside the ADU, extending the indoor space to the outdoor space through the accordion doors.  Photo by Carlos Rafael Photography

An outdoor patio is located directly outside the ADU, extending the indoor space to the outdoor space through the accordion doors.

Photo by Carlos Rafael Photography

And, when they’re in those spaces, people don’t want to feel like they’re out on display. People want to feel like they’re surrounded by the garden. Fences provide privacy and plantings do that too. Arbors give you that overhead plane that makes people feel a little more protected and enclosed.

 An entry arbor provides a sense of arrival to the property, while also indicating to visitors to that “ Yes, this is the pathway to get to the ADU in the back. ”  Photo by Carlos Rafael Photography

An entry arbor provides a sense of arrival to the property, while also indicating to visitors to that “Yes, this is the pathway to get to the ADU in the back.

Photo by Carlos Rafael Photography

Kol: What is your feeling about hardscaping solutions vs softscape solutions?

Joel: It’s primarily dictated by how people envision using the space and what furniture they plan to use.

Generally, I want to use as much softscape as possible to “green it up”. But, there has to be a balance. You want people to feel comfortable in the furniture that they have in that space. But, you want to have plants to soften it up.   When there’s not a lot of square footage remaining, I tend to use lush and dense plantings to give that sense of greenery.

For instance, a seating area for several people or a dining set can occupy a large percentage of the outdoor space of an ADU site.  I try to avoid having the hardscape come right up to a perimeter fence. It’s best to leave a small planting area for vines that can soften the hard edges.  

Kol: How do you use landscape lighting?

Joel: I try to encourage it anywhere.

At night, landscape lighting can highlight certain features in the garden and give you something to look at.  And, you can occupy those spaces at night and not feel like you’re in a black hole.

 Two forms of pathway lighting can be seen here in the foreground and in the distance. The distant pathway lighting is from the ADU, which is located off to the right beyond the fence. In the foreground, the low pathway lighting is for the primary house courtyard.  Photo by Carlos Rafael Photography

Two forms of pathway lighting can be seen here in the foreground and in the distance. The distant pathway lighting is from the ADU, which is located off to the right beyond the fence. In the foreground, the low pathway lighting is for the primary house courtyard.

Photo by Carlos Rafael Photography

Generally, there are two different levels of lighting.

The first level is for people to be able to navigate safely at night without tripping over things. And, that’s usually accomplished by path lights. In the Montgomery project, there were also pendants in the pergola.

The 2nd level of lighting is accent lighting. If there’s a specimen tree that you want to highlight with uplights, or if there’s an architectural feature, you can use a wall washing light on the side of a building.

Landscape lighting is a little bit of an investment.  A typical landscape lighting project may cost $1-2K. However, the ongoing expense is nominal with LED lighting is quite low… compared to traditional lighting.

Kol: Where do you put benches and decks in terms of the structures?

Joel: I try to create destinations in the garden. Those can be adjacent to the ADU or the house or more remote.  

Benches and decks that are right next to the ADU can provide a direct, physical link with the interior spaces and be an extension of the architecture.  

But, a lot times I like to push them a little bit away from the house.  I’m usually inclined to separate garden spaces so that there’s a bit of a journey to get to them. If you’re able to create a secondary space that is a little bit more remote, that creates its own little environment in the garden.

Kol: When and where do you use entry arbors/gables and gateways on properties?

Joel: Arbors are a doorway into the garden. It really gives you the sense that you are entering into the space. A gate can kind of do that, but if you have something on the overhead plane, your field-of-view is focused and as you pass through it opens up again.  So, I think it helps with that sense of entering into a distinct space.


Vertical covered planes like arbors give you a sense of enclosure and less exposure. When you are exposed, maybe it makes you feel like you can’t be yourself if you know people are watching you. If you feel like you are in your own space, and not on display, you can let your guard down and relax.

 A formal entry arbor.  Photo by Carlos Rafael Photography

A formal entry arbor.

Photo by Carlos Rafael Photography

Kol: What was the purpose of the Montgomery pergola? They’re genius.

 These archways frame the view down the pathway toward the ADU. Pendant lights serve to illuminate the pathway at night. Eventually, the plants along the right side of each arch, will grow up and over the arch.  Photo by Carlos Rafael Photography

These archways frame the view down the pathway toward the ADU. Pendant lights serve to illuminate the pathway at night. Eventually, the plants along the right side of each arch, will grow up and over the arch.

Photo by Carlos Rafael Photography

Joel: With this particular project, there’s Jasmine planted at the base of each archway. The intention is that those will grow up and fill in.  There’s also a lower hedge that will grow up to be be 5-6ft tall. The idea was to create a corridor for people to experience while getting to the ADU.

The homeowners didn’t want to reveal the ADU right away. The idea was that there was this corridor that people would walk through to get to the ADU.  Initially, your view is confined a little bit. But, there’s a hint that something is going on back there. Once you get to the end of the pergola is when the view opens up and you can finally see the whole ADU.

That’s the big reveal. There’s nothing overhead—just open sky and a beautiful building.  So, that was the sequence that we were thinking about there.

Kol: How and when do you incorporate water features?

Joel: As much as possible for auditory interest. It’s soothing to hear and watch bubbling water. Birds like it too.

I like to strategically tuck them away into planting areas so that you hear something as you enter into the space and it’s not obvious where it is right away. A water feature should be something you can discover in the garden.  Ideally, they can be positioned as a focal point and be heard from the major use areas.

 The water feature creates a soothing bubbling noise.  Photo by Carlos Rafael Photography

The water feature creates a soothing bubbling noise.

Photo by Carlos Rafael Photography

I have a water feature in my own garden that’s located directly outside our kitchen window.  In addition to being beautiful, my whole family enjoys watching the hummingbirds use it every morning… it’s a nice way to start each day.

Kol: Are there maintenance issues associated with it?

Joel: Every couple weeks, you need to stick a hose in there and refill the water level. But, there’s a 50 gallon basin underground and that holds and recirculates the water.

Kol: How much should this project cost for a landscaping a 5,000 sq ft lot? Is the estimate based on a cost per sq ft, or do you figure out how much materials will cost, then charge that amount again as labor?

Joel: I always use a rule of thumb that people should budget about 10% of the cost of the ADU construction for a landscape. It depends a lot on what’s included in the program, of course. So, for a $200K ADU, a budget of $20K for landscaping, should be expected.

I use a spreadsheet template for all my bids. It’s not based on square footage at all. There are too many variables.  For example, a water feature can be anywhere from $1,000 to $1,500… depending on the materials that are used.  I have a pretty extensive spreadsheet that I use to develop a fixed price bid for each project.

Kol: How much did the last two ADU landscaping projects end up costing to the customer, if you don’t my asking?


Joel: $30K and $20K.

 This is the landscape design plan for the Montgomery ADU project. The four arches can be seen in the lower right. The large paving slabs can be seen in the lower left, leading into the ADU.

This is the landscape design plan for the Montgomery ADU project. The four arches can be seen in the lower right. The large paving slabs can be seen in the lower left, leading into the ADU.

Kol: What value does effective landscaping bring to the table in a good ADU design?

Joel: In my opinion, having a garden that is functional and beautiful is priceless.  Gardens have the potential to improve your daily experiences. Improving your landscape is like adding rooms and livability to your house.  I’m sure the real estate industry has a general formula to determine the value of a fixed-up garden. But, I don’t know how you’d quantify a truly unique garden.  If you create a really cool space, how do you put a number on that?

Each of the ADU projects that I’ve worked on, are spaces the homeowners plan on being in for practically the rest of their lives. It’s not like a “flipper” who comes along and wants to finish their gardens as quickly and cheaply as possible.  My clients are going to use their gardens for a long time, so they’re willing to invest in them.

 The view of the arches from the ADU toward the front fence of the property.  Photo by Carlos Rafael Photography

The view of the arches from the ADU toward the front fence of the property.

Photo by Carlos Rafael Photography

Kol: When should someone consider landscape design in their overall architectural plan?

Joel: The sooner the better. I’ve encountered with a lot of ADUs or houses in general, where they’ll want to pour a slab right outside a doorway. But, that’s not necessarily what you’d want to do if you’re going to have pavers, or something like that which would require the slab to be lower.

Often I’m brought in after the architecture has already been done, so I have to respond to what’s happening and work around what’s already been built. But, I often encourage people that if landscape design can be done in unison with the architectural planning, that’s the time to do it. Because if they are going to be integrated, the indoor and the outdoor spaces, you want to consider both right up front.

End of interview

Here’s Haven Garden Design & Construction contact information.

https://www.havengardendesign.com

(503)367-7346

havengardendesign@gmail.com

*A final note from Joel* Through the years, there have been several books that I’ve found very informative and inspirational:

Garden Spaces by George Carter

Outdoor Spaces by Ana Canizares

Residential Landscape Architecture by Norman Booth and James Hiss

Small Space Gardens by David Stevens

Well Designed Garden by John Brookes