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Build Your Own Clematis Posts
by John Vicellio - posted 03/22/19

Clematis stands high on my list of favorite plants. I have designed and built a number of supporting posts just so I can add this beautiful plant to the garden in areas where other supports don’t exist. I don’t just build them for myself, I’ve also built posts for my friends. In total, I’ve created about a dozen posts, and while each one is different, the basics of building them are the same. 

Building a clematis post is an easy project. You will need an 8-10-foot-long, treated 2-by-4 or 4-by-4. When selecting lumber, it is essential that the pieces are straight. This can easily be checked before purchase: Lay each piece on the floor; it should lay flat its entire length; if it does, turn it on its side to ensure it’s straight that way as well. The other elements for your clematis post include a post cap, finial and a cylinder of wire. 

You can use various combinations of post caps and finials, porch railings and balusters, fence pickets and 1-by-2s, all pre-milled, treated and available at most home-improvement stores. The addition of different pre-milled features to a simple post adds interest and aesthetic appeal, so each one is unique. 

The foliage on most cultivars of clematis drops naturally in the fall, and vines will be pruned in anticipation of the next year’s growth. Consequently, there will be a number of months in our Carolina gardens when the post itself will assume an important visual role in the landscape, making decorative touches or even a bold paint color even more desirable.

Once you have the materials, you’re ready to build.

Step 1. Use galvanized deck screws of appropriate lengths to assemble the selected wood parts. For my most recent post, I attached two porch railings to the sides of an 8-foot-long 2-by-4, then placed an hourglass baluster on the front and a 1-by-2 on the back. I then stacked two different post caps on top and finished it off with a favorite finial. 

Step 2. Painting is optional, but it adds a finished appearance. Before painting, caulk the seams and spackle the screw heads and any knots. Then sand any rough spots or splinters and paint with exterior primer. 

Step 3. Attach a wire cylinder to the 1-by-2 with galvanized staples. Galvanized wire can be purchased plain or coated in 50-foot rolls at heights of 2, 3 or 4 feet. I prefer using 16-gauge, galvanized, green vinyl-coated lawn fencing. To get an approximate 12-inch wire cylinder I use wire cutters to cut about 39 inches of wire. Remember your high school math – circumference equals diameter times π (3.14). 

The height of the wire will vary according to the height of the post aboveground. I have learned to leave the bottom of the wire about 6 inches aboveground. This minimizes leaf collection over the winter at the base of the post.

Step 4. Paint your post. After attaching the wire, use approximately a can and a half of spray paint, painting both the post and the wire.

Step 5. Using a post-hole digger, dig a hole about one-quarter the height of the post. Be sure to pick a location that receives at least six hours of sunlight.

If you live in a region with heavy clay, tamp the clay around the base with a spare 2-by-4 to get a secure hold. This has the added benefit of making it easy to lift the post and move it to a new spot; I brought two of the posts to our new garden when we moved. The other option is to use pre-mixed concrete. Build up a shallow slant away from the base, allowing water to drain away from the post and ensuring the post is plumb.

Now you’re ready to plant your clematis. Prepare a deep and wide hole, working in copious amounts of soil conditioner and composted manure to the existing soil. Plant the crown several inches below the soil line, encouraging the plant to put out multiple stems and helping the plant recover from clematis wilt, a common problem in the Carolinas. 

Protect the plant from drying out, particularly in its first year, but do not overwater. I have planted coreopsis and scabiosa at the base of my clematis to shade its roots and help the plant to retain moisture. I also apply a small amount of 5-10-10 fertilizer around each plant as the buds start to swell in spring.

There are basically three pruning regimens for clematis: spring tip pruning, cutting down to short stems just above the first big swelling buds in the spring or no pruning at all. There are hundreds of cultivars available, so ask an expert at your garden center which pruning method you should use for the type of clematis you have. 

Some experts recommend keeping a newly planted clematis pruned to about 18 inches the first year, allowing most of the energy to go into a strong root and stem system. When I planted a new ‘General Sikorski’, it grew so well that I didn’t have the heart to cut it back that first year. After it bloomed in the spring, I did prune it. You can image how pleased I was when it put out vigorous new growth and rebloomed in late July. I’ve followed the same regimen each year with similar results. Last year it responded to a second pruning with a small, but very welcome, third set of blossoms until the first hard frost in December. 

For posts seen from only one side, you can plant a single clematis. For those that can be seen from both sides, I select two clematis with complementary colors, similar growing height, overlapping bloom periods and most importantly, similar pruning requirements. Two successful combinations in my garden are ‘Henryi’ with ‘Pink Champagne’ and ‘Ramona’ with ‘Jackmanii’. 

I use my posts exclusively for clematis, but they can easily be adapted for other vines or as supports for birdhouses or feeders.

 

This article appeared in a previous issue of State-by-State Gardening.
Photography by John Vicellio.

 


John Vicellio is a master gardener and writer who began to garden seriously after he retired from the Navy.