Garden Obelisk/Trellis Made From Rebar

An obelisk can be an attractive addition to any garden space and it's a practical way to support climbing plants, such as roses, clematis, and various vegetables. As a gardener with limited space, I have been looking for ways to grow more plants vertically, especially plants that take up a lot of real estate, such as squash and zucchini.

The obelisk illustrated here is easy and quick to build and uses commonly available steel rebar. To add some decoration, it is topped with a cast iron finial (source provided).

Materials Needed:

• 40' of 3/8" rebar (available in 10' lengths for about $5)
• four pieces 7'
• four pieces about 12"
• four pieces about 10"
• four pieces about 7"
• four pieces about 4"
• 1" Cast Iron Finial. Purchase the "square cap" version as shown in the third photo above. Available from Steel Supply LP. Cost is between $4 and $13 each (plus shipping), depending on style. I bought four and the shipping cost was the same as purchasing one. Another source for finials and other decorative metal castings is King Metals.
• 18"x18" (or larger) piece of scrap 1/2" plywood or OSB

Tools:

• Welder (arc, MIG) and associated welding gear (welding helmet, gloves, etc.)
• Bench Vise
• Hand drill with 1/2" wood drill bit
• Angle grinder with cut-off and grinding wheel
• Tape measure
• Sharpie or paint pen
• Safety glasses
• Hearing protection
• Gloves

I used an angle grinder to cut the rebar. A rebar cutter or hacksaw will also work. I made this obelisk just over 7' tall and the lengths of rebar needed are based on that height. If you want a shorter (or taller) obelisk, no problem, just cut the four legs to the length you desire and adjust material needed accordingly. Make sure all the legs are the same length....your obelisk will come out crooked if lengths differ.

I made a simple jig to assure that the legs of the obelisk would remain spaced correctly as I welded the supporting cross pieces. I used a scrap piece of OSB 18"x18" and drew a 16" square on the panel. I then drilled 1/2" holes at the corners of this square. If you want a shorter (or taller) obelisk, you might adjust the square size so the scale of the obelisk is pleasing to the eye.

Bundle the four 7' legs and secure both ends with some stiff wire or tape to hold the pieces tightly together. Tack weld one end and then permanently weld the four pieces together with a 1" long weld as shown. Test fit the cast iron finial over the welded end. It will likely be loose and floppy. Built up more weld bead on all four sides until the finial fits snugly over the welded end. If it won't fit, grind or file off metal until it slides on with some friction. This is important in a later step to get the finial welded on plumb.

The four 7' legs are straight at this point, but they need to be "flared out" a little to fit in the wood template and give the obelisk its angled stance. Stand the welded legs in the vise (or alternatively, place horizontal, if necessary) as shown. After tightly clamping, slightly bend each leg a few degrees at a diagonal. The third photo shows one leg bent. Bend as close as possible to the weld and try not to over bend. It won't take much of a puIl to get the bend you need. It may help to get a extra hand for this step. Ideally, you should see the end of the leg flare out about 8"-10". If you have bent correctly, the legs should fit, without too much persuasion, into the wood template holes. If not, you may have to rebend the legs a little to fit.

Stand the welded legs in the wood template. Place the finial on the top (you may need a ladder) and make sure it fits snugly. Stand back and eyeball the finial from all sides and adjust it to make sure it is plumb. This is why you want a good friction fit, so the finial doesn't move around while welding it to the legs. Weld the finial to the top of the obelisk while in this position. You don't need a lot of weld to secure the finial.

Place the end of a tape measure on the wood template and measure up the leg. For this obelisk, I marked every 16" on all four legs. Of course, you can put cross pieces at whatever spacing you desire. Mark accordingly, but know that you might need more rebar if the spacing is closer than the 16" I used.

I recommend starting with the bottom rung of cross pieces and working your way up to the top of the obelisk. Measure the width of the legs on two opposite sides at the 16" marks. For the first rung, the distance to the outside of each leg should be 12"-13" and should be about the same measurement on the other side. If not, take the average of the two measurements and cut two pieces of rebar that length. Weld on opposite sides as shown in the second photo. Repeat for the upper rungs. Next, work on the opposing cross pieces, working your way up the obelisk. You may need to flex the rebar some as rebar is not always perfectly straight. Don't worry if it is not exact. This is a plant trellis, not a NASA space module. My first trellis was out of square and a bit a kilter. The plants don't care and no one notices.

The last step is how you want the obelisk to look, color-wise. Personally, I like the look of rusted metal outdoors, so I sprayed some vinegar on the obelisk to speed up the rusting process. I will let it continue to weather naturally. To paint or not to paint, that is up to you. And that's it. You are finished.

I have made several garden obelisks. While construction using a finial is the easiest many other design options exist. The first photo shows a 10' tall oblisk that I flared out the top of the legs by bending each piece in a vise. The linked Youtube video is a good tutorial on bending rebar. This obelisk was trickier because I couldn't preweld the four legs before standing it up and it takes more than two hands to erect the legs, hold them in the template, and get the curved tops at a 90 degree angle. Get some extra hands if you attempt this one. The second photo is an three legged obelisk that I welded a piece of black iron pipe in the middle of the top of the legs to accommodate a decorative top of a broken copper garden sprinkler that I salvaged from a trash bin. It also required extra hands. An infinite number of design possibilities exist that are only limited by your imagination. Go nuts. Be creative. Have fun.