Clematis petriei

Clematis of the Month for October 2022

described by Fiona Woolfenden

Clematis petriei male flowers growing in the wild

In October 2018, we were lucky to see Clematis petriei in flower growing in the wild. C. petriei is native to New Zealand and we were on holiday there for a couple of weeks. We had met Joe Cartman (who has had a clematis named after him, C. ×cartmanii 'Joe') a few days earlier and we saw one he had in a pot in his garden.

C. petriei male flower growing in cultivation

The plant we saw in a pot in Joe's garden was a small male plant with many flowers. It had slightly bigger flowers than that we saw flowering in the wild and this could have been because the plant was growing in better soil or compost and the flowers had been open longer and were more advanced. The flowers were 3-4 cm across, with 6 sepals and they were a lovely yellow colour.

New Zealand species clematis plants are dioecious plants, so plants are either male or female and have either male or female flowers respectively. The flowers are green, white or cream and usually small. Some are scented. C. paniculata which has white flowers also has the largest flowers. The species are generally referred to as 'evergreen' as they don't lose their leaves over winter. Several species, such as C. afoliata, have no leaves or very small leaves. See the Previous Clematis of the Month articles for more information on a number of the different species at https://www.clematisinternational.com/cotmfor.html.

State Highway 73

Joe gave us directions to find C. petriei growing in the wild when we drove from Christchurch to the west side of South Island using State Highway 73 which crosses Arthur's Pass. Joe told us how to find a place where there were some C. petriei plants growing which he thought should be in flower. These were in the Korowai/Torlesse Tussocklands Park which is located between the town of Springfield and Porters Pass. We found the Torlesse Tussocklands Park and found C. petriei. We were amazed that we were able to follow Joe's instructions and find the plants.

C. petriei male flowers

The flowers were only just opening, and we only saw male plants in flower. The flowers were a pale yellow and a little over 3 cm across with 6 sepals. I did not notice a scent – it is supposed to be fruity. There were some plants with buds and we wondered if these were the female plants which had yet to flower. Female plants usually flower later than the male plants.

C. petriei female flowers? growing in Discaria toumatou

C. petriei growing in a bush

The Park was composed of bushy scrubland which looked very dry even this early on in the year. C. petriei was growing in some very thorny bushes called Discaria toumatou. The tallest cluster of C. petriei we saw was about our head height. There were a number of plants in this area.

Joe visited the Torlesse Tussocklands Park a week or so later in October 2018 and commented to me that there were quite a few plants in flower but also a number that were not going to flower this year.

C. petriei was originally classed as a separate species but in work published in 1988 it was included in in a species complex with Clematis forsteri. It was reinstated as a separate species due to the further work undertaken by P. B. Heenan & Joe Cartman which was published in 2000 and reprinted in the Society's Journal, Clematis International 2003, along with the late Dr. Mary Toomey's excellent succinct précis.

This article is based on an article in Clematis International 2019, pages 73 and 76.

Fiona Woolfenden