Building An Inviting Garden Trellis

A decorative trellis is the way to go when separating parts of your yard.

Wow, what a difference!

All About

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Homeowner Dan Goldman wants to separate his hot tub area in the side yard from the backyard. Landscape architect Shili Lu suggests a trellis instead of a gate to separate the two yards because the trellis offers more charm and also invites guests into the area beyond. Lu's design includes a seating area and a flagstone path. She'll use lots of lavender and blue color in the yard and will plant fragrant roses and herbs to create a Provence-style garden.

The site: the view from the hot tub of the bare yard and overgrown vegetation will be transformed with a trellis and plantings.

Finishing the project will cost Goldman only $800 if he does the work himself; hiring a professional would cost about $2500. Neither estimate includes the cost of plants. The project rates a difficulty level of "3" on a scale of 1 to 5, with 5 being the most difficult. It should take the average do-it-yourself homeowner about two weekends to complete.

Step One: Building the Trellis

Clear the area, removing any shrubs, roots or rocks. Next, add new soil and level it with a rake. Carpenter Tim Rice is using clear, all heart redwood 4 x 4s — he says clear means there are no knots in the wood, and all heart means the wood is from the center, or heart, of the tree. You can choose knotted redwood if you want to cut costs, says Rice. He outlines the steps involved as he constructs the trellis:

Figure A

Begin by measuring the width of the back yard and marking the center with landscaper's paint.

Mark points on each side of the center where you will be placing your 4 redwood posts (figure A). Rice's marks are set for a trellis that's 4 feet wide and 2-1/2 feet deep.

Dig four 18-inch deep holes with a post-hole digger, making sure they're wide enough to hold a 4x4 post surrounded by 2 inches of concrete.

Figure B

Tips: Rice suggests using a concrete mix that already contains sand, cement and gravel so all you need to do is add water. Mix the concrete to a fairly stiff consistency (figure B) to help lessen the setup time. If you do it correctly, it should take two hours to set and two hours per hole to dry.

Place the posts in the holes and fill around them with concrete. Build the concrete up about two inches above ground to keep soil away from the posts (when the soil gets wet it can cause the posts to dry rot).

Check to make sure the posts are plumb as you go and let the concrete set for two hours.

Step Two: Building the Crosspieces

Rice is topping the trellis with a series of crosspieces made from 2x8 redwood posts. He sandwiches those between the 4x4s and adds a decorative cut on each end of the 2x8s. He places notched 2x4s on top of the 2x8s.

To create the notched design for the 2x8s, create a template from a scrap piece of wood and trace the design on either end of the posts.

Cut to shape with a jigsaw.

Set the posts about 7 feet high to leave room for the finishing touch, a decorative arch on top.

Figure C

Attach temporary blocks to the 4x4s (figure C) to set the 2x8s on as you hold and attach them to the 4x4s.

Secure the 2x8s with three-inch galvanized screws.

Figure D

Line up another beam across from the first to sandwich the 4x4s (figure D) and attach.

Cut off the tops of the posts so that they're even with the 2x8 beams.

Cut 2x4 crosspieces at a 60-degree angle for a decorative look, then notch the ends with a jigsaw to create a snug fit when you place them on the 2x8s.

Figure E

Slip the crosspieces on the beams, spacing them evenly apart and secure them with screws (figure E).

Planting Plan

Lu is using trailing vines to cover the trellis and low hedges as an enclosure around the trellis. She's planting groundcover between the path stones to mimic the traditional French country style. Some of her choices include:

Butterfly bush (Buddleia davidii) 'Black Knight', Zones 6-9

Lemon thyme (Thymus citridorous) Zones 6-9

Lavender (Lavandula dentata) Zones 8-9

Figure F

Step Three: Finishing the Trellis

Rice says the challenge to creating the arch for the top is making round wood out of a square board. The key is to create a radius point, transfer that to a plywood template and cut the template out. Trace that template onto the redwood and cut.

To make the template, you need to set the arch key, or the top setter point of the arch. Position a 4x4 block (figure F) four inches from the bottom of the beam, so that the bottom of the block rests at 6' 8," or the standard height for doorways.

Figure H

When the arch key is fastened in place, attach a large piece of quarter-inch plywood to it (figure H).

Find the radius of the arch by measuring between the post and the post key, about two feet, then measure two feet from the bottom of the beam down the post as well.

Mark the intersection of these points on the plywood--that is the radius point.

Attach a measuring tape to the radius point with a nail and use that to trace the outer arch.

Trace another arch four inches in from the outer arch to create an inner arch.

Cut this template out with a jigsaw, then use it to trace four half arches on a 2x2 plank.

Figure I

Once they're finished, attach them to the arch key and posts to complete the arches on either side (figure I).

Figure J

Rice wants to enclose the trellis with lattice for a classic garden feel, so he builds an outer frame from redwood 2x2s, then attaches evenly spaced vertical pieces to the frame. He sandwiches horizontal pieces, spaced evenly, between the vertical pieces to create the lattice look (figure J).

Step Four: Completing the Area

To create the seating area, follow these steps: <

Define the shape of the area with bender board.

Rake the area so the soil is level.

Cover the area with a thin cushion of dirt and rake it as well.

Add a six-inch layer of lava rack (Lu says this is available for about $27/cubic yard).

Tamp the rock with a hand tamper to crush it and create a fine surface.

Figure K

Building the path is almost as easy as creating the seating area: Lu uses peach flagstone that costs about $260 per ton (figure K). She marks a meandering path and lays the stones out--she says to be sure to walk the path to make sure it's an easy stride.

After you're sure where you want to place the flagstones, dig a shallow two- to three-inch cavity under each stone. Fill the cavity with a couple of inches of sand and set the stone firmly in place, tapping it firmly into place with a rubber mallet. Do this for the entire path, add a table and chairs to the seating area and you're finished.

Resources

Guests
- Shihli Lu
  Landscape Architect, Feng Shui Landscape
  1087 Warfield Ave.
  Piedmont, CA 94610
  Phone: 510-835-5498
  Email: shihlilul@yahoo.com
- Tim Rice
  Contractor
  Rice Construction
  Novato, CA
  Phone: 415-892-4884