Help your garden grow up with a mini-monument for climbing plants.
My wife is an avid gardener, and I love woodworking. We’ve been able to create some nice projects by combining these two passions, including the garden obelisk featured here. These wooden steeples can be attractive punctuation marks in many yards and gardens, creating focal points that integrate architecture with the natural beauty of climbing plants.
We found that the wooden obelisks we purchased were too easily damaged; their nailed-together joints can’t stand up to New England’s blustery weather. Why not make a “woodworker’s obelisk,” that can provide any yard with a peak experience, while standing strong and long?
If you like this design, I suggest buying enough lumber for two or more. Even if you only use one in your garden, any friend with a green thumb is sure to want one.
Order of Work
- Set up the work board.
- Groove the post’s inside edges.
- Cut the rungs to length, then cut tongues on the rung ends.
- Glue up the base and trim the post ends.
- Make and install the peak assembly.
- Make and install the trellis assemblies.
Posts, rungs, and a decorative peak
I ripped all my post and rung stock from cedar 2×6 decking boards, then planed this material 1-3/8" square before cutting parts to finished length. Cypress and pressure-treated pine are also good outdoor wood choices. Whichever wood you choose, make sure to select clear stock, since knots will weaken the structure. Use the leg and rung lengths given on the drawing for basic reference; their actual measurements should be taken directly off the pattern you make on the work board (see p. 52).
Make a work board to ensure accurate layout and super smooth assembly
With so many angled joints to lay out, cut, and assemble, it helps to have a flat work surface that contains a full-scale pattern of the post-and-rung assemblies you’ll be building. I made my work board from a piece of inexpensive, 1/2" CDX plywood, coating the work surface with primer so my layout lines are clearly visible. After laying out the posts and rungs, screw cleats down the center of your board at each rung location. You’ll use these to clamp rungs in place during assembly. When your work board is complete, record the length of each rung (including tongues), and start cutting your parts to size.
Tongue & groove joints on the router table
To speed and simplify the joinery work, I milled a pair of grooves along the length of each post, then set up a quick way to cut matching tongues in rungs. This work gets done on the router table. It’s important to offset the grooves in your posts as shown in the drawing (p. 51) because centered grooves will weaken the post. Make sure to have some scrap rung stock on hand, so you can mill some sample tongues and make any adjustments necessary for accurately made joints.
4 posts, 20 rungs, 40 joints
Use the work board as an assembly aid to keep parts aligned as you make each tongue-and-groove connection. Titebond III is good to use for this build; it’s waterproof and easy to apply, with a longer open time than other outdoor glues. Use a small brush to coat each tongue with glue, and press your post-and-rung joints together to assemble the first ladder frame. Then repeat this procedure to complete the opposite frame.
Joining the two ladder frames together demands some nimble maneuvering, because you’re installing 10 rungs at once. To aid the assembly process, use a chisel or some sandpaper to create a slight chamfer on the end of each rung’s tongue. This will avoid snags when getting joints engaged.
Complete the base assembly. Start the glue-up by clamping a set of rungs to their work board cleats, as in the previous step. Then stand both previously assembled frames on edge to engage the tongue-and-groove joints. When the lower set of joints are loosely clamped, you can begin to install the opposite rungs. Tap joints into alignment as necessary, then tighten your clamps. I reinforced each joint with a pair of 11⁄4" stainless steel finish nails.
Use a cutting guide to trim post ends. Make the guide from an L-shaped blank, as shown in the drawing. Clamp it to post tops and bottoms where you want to make your level cuts, and use the angled faces to guide your saw.
Now peak at the top
An obelisk needs a nice crowning touch. The peak detail I came up with is easy to build. It consists of a square cap frame made from four identical mitered pieces, and a peak assembly made from four 12"-high wedges that surround a pointed centerpiece. I cut the wedges with my circular saw, then clamped all four together to saw the decorative triangular cutout.
Trick out your tower with a trellis
Now it’s time to put the finishing touches on your obelisk, in the form of four trellis assemblies that overlay the frame. Made from lap-jointed, 3⁄4"-square stock, these delicate details add visual appeal, while also providing many more anchor points for climbing plants.
Finishing Tips
Outdoor woods like cedar and cypress will weather to a nice natural patina without any protective finish, while also resisting rot. But if you plan to treat your obelisk to an outdoor finish, apply your finish coats while the base, peak, and trellis assemblies are separate. You’ll get more complete coverage, and have a much easier time with finish application. Suitable outdoor finishes include milk paint, outdoor stain (semi-transparent or solid color), and exterior varnish.
