Lavender Fields

Hillary and Chris Costin, owners of a handsome home on a picturesque lot in the San Francisco Bay area, want to add color and fragrance to the large, unadorned hillside that borders their backyard. Having decided not to use the area for any specific purpose, the homeowners want to cover the expanse with fields of lavender, which will provide a beautiful source of cut flowers. Once cut, the lavender can be used in arrangements, as potpourri or as a source of lavender essential oil.

To implement this unique project, landscape designer Louise Leff sets to work creating a landscape plan for the hillside that includes a meandering pathway and a flagstone patio in addition to the lavender fields. Leff explains that this site is ideal for lavender, which requires full sun and excellent drainage. In fact, the plants will rot if they're not able to dry out between waterings. She also points out that the hillside is easily visible from the house, which means the homeowners will be able to enjoy the magnificent view on a daily basis. A small seating area on the patio will provide an outdoor vantage point.

Leff explains that this project would cost around $10,000 if professionally installed, whereas the average do-it-yourselfer could purchase the required materials for about $2,000 and complete the work in three to four weekends if working with a friend. On a difficulty scale of 1 to 5, with 5 being the hardest, Leff rates this project a 4, commenting that working and planting on a slope is the project's most challenging aspect.

To get started, the crew first marks out the planting rows with landscape marking paint, leaving about five feet between rows. This will allow plenty of room for walking among the rows even after the plants are full-grown. Leff aligns the rows so that they'll form an inverted V that extends outward from both sides of the pathway, adding visual interest.

Leff explains that the course of a path should be determined by the easiest and most interesting route across a given area, one that provides a variety of views as it progresses. After deciding on the placement of this path (up through the fields to the top of the next hillside), Leff uses landscape marking paint to mark its outline.

Next, the crew uses a rototiller (about $55 per day to rent) to turn the soil along the rows--the difficulty here is keeping the rows straight on such a steep slope. Leff says the rows should be leveled somewhat during this process to make planting easier.

Once the rototilling is complete, it's time to add the irrigation system. Leff recommends running drip irrigation to all rows and placing emitters every 12 inches. (In extremely dry climates, it may be necessary to install two irrigation lines per row.)

Step Two: Planting the Fields

When you're purchasing plant material, Leff advises choosing young plants such as the two-inch-high lavender plantings used here. The cost of young plants is reasonable (about a dollar per plant), which is a major plus when dealing with a large area such as the quarter of an acre covered in this project. Smaller plants are also easier to acclimate to a new environment than their more mature counterparts.

Along the rows the crew spaces the plants about three feet apart, making sure that each one is located next to an emitter. Although the spacing may seem excessive at planting time, the lavender will quickly grow to fill in the spaces.

Next, the crew mulches the young plants with chipped wood mulch, which will help the soil retain moisture and won't get matted down over time. After two good growing seasons, the fields will be filled with beautiful color and will emit a fabulous fragrance. (Leff explains that lavender is relatively low-maintenance, requiring only a simple cutting/harvesting twice a year to keep the plants healthy and prevent them from becoming overgrown.)

Step Three: Building Paths and Adding Plants

To get started on the path, the crew first digs out the area along the outlines to create a shallow bed several inches deep. Next, they fill in the bed with road base, a type of angular gravel used in constructing roads and available in most landscape-supply centers.

Crew members use a rake to smooth the road base, then compact it with a hand tamper and a large water-filled roller (the roller is particularly helpful for long stretches). Then they top the pathway bed with crushed rock, which they smooth to create a uniform surface. (Decomposed granite is used here, but rock selection varies based on your locale.)

Once the path is complete, Leff turns her attention to the planting plan, which features an edging of perennials along the pathway that will break up the future blanket of vivid purple. Perennials will also be added around the border of the soon -to-be-built patio, helping to integrate it with the landscape.

Tip: When planting perennials in the ground, Leff recommends first placing them in "gopher baskets"--small wire-mesh containers--to protect them from pest damage.

The following plants are featured:

• Lavandula angustifolia, Zones 5-8
• Lavandula x intermedia 'Provence', Zones 5-8
• Mexican daisy (Erigeron karvinskianus), Zones 5-7
• Yarrow (Achillea sp. 'Fireland'), Zones 3-8
• Eulalia grass (Miscanthus sinensus 'Adagio'), Zones 4-9

Step Four: Building the Patio

To create a patio directly below the lavender fields at the base of the hillside, contractor Karl Frank conceives a design with retaining walls along the front and back for support (the front wall will support the patio, and the back wall will support the hillside).

The patio is constructed of three-rivers stone to match the home's existing patios, but Frank points out that this type of stone is substantially more expensive than many others: selecting another variety could cut the cost of the patio in half. The walls are created with three-rivers ledge stone, whereas the plane of the patio is fashioned from large sections of three-rivers flagstone .

The crew begins constructing the patio by outlining the area with landscape marking paint. Next, they dig out the area, cutting into the slope to create an almost flat plane but allowing it to tilt slightly to encourage drainage. Then they lay a layer of road base, which they smooth out with a water-filled roller before pouring a one-inch layer of sand over the surface. (The roller is used to compact the sand as well.)

After the bed has been prepared, the crew constructs two retaining walls along both ends of the patio. To create a base for the walls, they dig shallow trenches (about seven inches deep) where the walls will stand and fill them with concrete to create an anchor for the first layer of ledge stones. These stones are laid directly into the concrete, with subsequent layers of stones mortared on top. To complete the wall, the crew adds a flagstone cap that will provide extra seating.

Once the walls are complete, the crew begins laying the flagstone in place. As the pieces are laid on the sand, they're checked individually to make sure they're level. Frank explains that the shapes of the stones should be arranged to yield the best possible fit but notes that it may be necessary to use a masonry saw with a diamond blade to modify the shapes of some of the stones. (Masonry saws can be rented from tool-supply shops for about $60 per day, with an extra fee charged for wear and tear on the blade.)

Once all the flagstone pieces have been positioned and cut as needed, the crew fills the crevices with crushed rock (the same decomposed granite used for the pathway), sweeping it evenly over the surface so that it uniformly fills the gaps.

Finally, the crew wets the surface to compact the crushed rock and wash the excess off the surface.