Tom Karwin, On Gardening | Right Clematis, right place

Peninsula Premier Admin

Care for your garden

As a follow-up to last week’s breakdown of the plant selection for a particular site, this column considers the selection of plants a specific genus, in this case, the Clematis.

I intend to add two of these plants to my garden. One will replace a Clematis armandii, which I removed recently to make way for the painting of my house. This plant was growing on a downspout cover trellis (also called a tube trellis), which can be searched for on Google.

This plant was growing not just well, but too well. It had grown rampantly to beyond  20 feet high. Instead of draping itself horizontally over a trellis, as I had intended, it went straight up to the roof line. Who knows what the future experience would hold?

I have learned since that a regular pruning plan could have kept this plant behaving more as intended. I could have controlled by cutting down almost to the ground each year after flowering, but it was then too late for careful training. It was time to prepare for house painting (and, as it happened, also downspout replacement).

Once the painting was completed, I needed a new Clematis for the downspout cover trellis.

I also could use a second Clematis for a second downspout cover trellis, about 20 feet away from the first.

I researched the genus Clematis on the internet to support the plant selection process and to avoid the errors of the previous Clematis.

The Clematis, a native of China, is in the Buttercup family and related to the Ranunculus, Delphinium, Thalictrum, and Aconitum, and about three dozen other genera.

There are about 300 species of Clematis, and a large and growing number of both selected varieties and hybrid cultivars, reflecting its great popularity among gardeners.

These many options create the need for a plant selection strategy to choose the two new Clematis for my garden. Any Clematis would grow well with the full sun exposure of my two locations, so I could focus the selection process on mature size, blossom color, and pruning needs.

To begin, the genus can be divided into three pruning groups:

Spring Bloomers: vigorous species and hybrids that do not require pruning, other than to occasionally remove tangled growth.

Late Spring – Early Summer Bloomers: large-flowered hybrids blooming on the previous season’s growth that can be pruned lightly in the dormant season for structure.

Summer – Fall Bloomers: hybrids blooming on the current season’s growth that can be pruned back to a pair of buds in the dormant season.

There are numerous choices within each of these pruning groups. Useful online lists are available at

These lists are helpful for zeroing in on bloom times and pruning plans, but do not provide blossom colors or mature size for the many cultivars.

Another very important consideration is the availability of the selected plant.

There are many sources of this popular plant. While browsing YouTube for more information about growing Clematis, I learned about Brushwood Nursery, in Pennsylvania, a mail-order nursery that specializes in Clematis. Its website includes descriptions of numerous cultivars and, importantly, lists a large selection of “Clematis in Stock,” which much more options than the offerings of local garden centers.

Brushwood Nursery offers gallon-size plants (not seedlings in four-inch pots) and provides free shipping! While I haven’t yet received any plants from this nursery, and therefore not ready to endorse it, I like its style.

Brushwood’s current availability list is searchable by various filters, e.g., bloom time, pruning group, etc., and sorting categories, e.g., name, price, etc.

After choosing a filter and a sorting category, the site provides a close-up photo of each cultivar that meets those criteria. This process still requires clicking on each appealing photo to learn more about the respective plant. Choosy gardeners will need to schedule time for this selection process.

As with my previous column on plant selection, I will report my choices in a future column because your garden decisions should reflect your own criteria and preferences.

Advance your gardening knowledge

Last week’s Cactus & Succulent Society of America (CSSA) webinar, “The Amazing North of Patagonia: A virtual journey through the province of Neuquén,” was a broadening experience, to be sure. Presenter Elisabeth Sarnes provided both expert knowledge of the rather obscure cacti of this region of Argentina, and a concise overview of Patagonia’s terrain and flora. I did not enter into this webinar being curious about this region, but I found the session to be interesting and satisfying. Its success was due largely because of Sarnes’ thorough preparation, very good photos and well-organized clear commentary.

The “take away,” as I have suggested previously, is that the gardener’s investment of a little time in a webinar on an unfamiliar gardening topic can expand one’s gardening world. This particular webinar did not make me thirst for Patagonian cacti (most of which I found unappealing), but I learned about several previously unknown cacti, another area of the botanical world, and the impressive diligence of a plant hunting couple from Germany.

The CSSA has new webinars every two weeks. Its next event, on Feb. 20, will be a presentation by Gregg Starr on plants of Oaxaca, Mexico. Next week’s column will provide more details, but mark your calendar if you are ready to learn more on that topic.

Enrich your gardening days

The possibilities of gardening, whether in a small or large area, stretch out in several directions, so the exploration is never ended. It depends on the individual gardener’s openness to new information and willingness to grow unfamiliar plants and pursue innovative designs. A garden filled with well-established plants offers levels of comfort and botanical quality, while continuing evolution of the landscape and the introduction of new selections supports waves of fascination.

Enjoy your garden!

Tom Karwin is past president of Friends of the UC Santa Cruz Arboretum, Monterey Bay Area Cactus & Succulent Society, and Monterey Bay Iris Society, and a Lifetime UC Master Gardener (Certified 1999–2009). He is now a board member and garden coach for the Santa Cruz Hostel Society. To view daily photos from his garden, To search an archive of previous On Gardening columns, visit

Contributed by local news sources

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