Weekender: Garden obelisk

Trellis obelisks are favoured by many gardeners as decorative focal points. "They're elegant, formal, traditional," explains Beckie Fox, editor-in-chief of our sister magazine, Canadian Gardening. "You can use them at the beginning of a path, or at the centre of a formal vegetable garden. A pair can mark a stairway leading up to a terrace." They also make excellent homes for a wide range of vines and other plants -- you can rotate the obelisk to expose each side to the sun. And our design features simple, knockdown portability. The top half of the tower is attached with just four screws, making it easy to unfasten and bring the stand and pot indoors if desired.

Start at the Bottom
Despite its size, this project is simple to build; no fancy joinery or tools required. Start by cutting the legs, cross supports and support blocks. Build two flat leg frames, then join them into a box in a second step. Use outdoor glue and one 2 1/2"-long deck screw at each joint. Complete the base assembly by custom-cutting the diagonal angle supports, and fastening them to the sides of the structure using glue and 1 1/2" finishing nails.

The base also includes a grid that supports the plant pot you'll use later. It's built separately and fastened to the inside face of the cross supports with 1 1/2" deck screws. Cut the inner grid members now, and clamp them together so their notches can all be cut at once. This will speed your work and ensure your notches are perfectly aligned. Assemble the long, short and inner grid members into a frame using 1 1/2"-long screws and glue. Securing the grid within the base will add strength to the structure.

Building the Top
The angled top part of the planter sits on a biscuit-joined, mitred frame. Assemble this now, then add the four corner posts, following the cutting directions above. Use two 1 1/2"-long deck screws through each corner of the bottom frame into each corner post. Four similar screws driven down through the top cap base secures the upper ends of the corner posts.

The centre strips and chevrons fasten to the planter's top with glue and 1 1/2" finishing nails. The ready-made top cap ball is designed for use on a fence post but also works well here. Glue it onto the top cap base.

A project of this sort is too intricate to paint or varnish, but it is practical to protect it with a penetrating sealer or oil. My wife Sandy applied one generous coat of tung oil to our tower with the intent of applying more every year. You could also use boiled linseed oil or a silicone-based water repellent. Whatever you do, don't apply anything that forms a surface film. If it ever peels (and it probably will one day), you'd never find the courage and patience to scrape it all off.