Tag Archive for: Cirsium hillii

The beginning of the New Year has been busy with new seeds arrivals. Having a new garden space means also having new plants interests. Therefore, I declare 2016 as The Year of the Thistle!

According to wiki, “Thistle is the common name of a group of flowering plants characterized by leaves with sharp prickles on the margins, mostly in the family Asteraceae”. But besides the ‘true thistles’: Cirsium, Carduus and Onopordum, other genera that don’t have spiny leaves are also included and called thistles: Jurinea, Centaurea, Carthamus, Carlina, Rhaponticum, Echinops, Silybum, Berkheya and so on.

Few plants are more beneficial to bees, bumblebees and butterflies than thistles; also, many birds are consuming their seeds. Quite a few are cultivated as economical/medicinal plants. The oldest cultivated ‘thistle’ in the world was Carthamus tinctorius (safflower).

Unfortunately the name ‘thistle’ brings to mind mostly awful weeds. However, there are many species that are non-invasive and highly ornamental; some are even endangered in their wild habitat! To name only 2 North American Cirsium species that are not weedy and have become endangered: the endemic Cirsium hillii (C. pumilum var. hillii) – seen in the image, and C. pitcheri. Cultivated in the gardens but not too often is Cirsium canum (Queen Anne’s Thistle).

A most interesting genus is Jurinea. These are species familiar mostly to plant collectors; the genus includes alpine/sub-alpine species growing in mountain meadows, a few rare and/or endemics. In the image is shown Jurinea mollis growing in a sub-alpine meadow in the Carpathian Mts.

Jurinea mollis in Carpathian Mts.

Jurinea mollis in the Carpathian Mts.

Other great species practically unknown in cultivation are Jurinea iljinii – with a restricted distribution range in the western part of the Greater Caucasus, and Jurinea sordida endemic in Crimea. They all have in common, non-spiny, finely lobed leaves and purple (in various shades) flower heads, which take on a beautiful silky appearance when the seeds are ripened.

Jurinea mollis seedhead

Jurinea mollis seedhead

There are also nice, low-growing Jurinea ssp. for the rock garden (if you can find seeds) like J. depressa and J. macrocephala, to name just a couple. From the low-growing thistles category, I will have to contend for now with the alpine thistle: Carlina acaulis. You can read more about it here.

Carlina acaulis

Carlina acaulis

To be continued…

Thistles gallery

Alvar is the name used for a distinctive habitat formed by a thin covering of soil or no soil at all, over a base of limestone or dolostone bedrock. These alvars support specialized species communities and are found only in the North America Great Lakes Basin, Estonia, Sweden, Ireland and UK. Ontario contains 75% of the alvars in North America.

Campanula rotundifolia and Packera paupercula

Campanula rotundifolia and Packera paupercula

I find the extreme conditions in which plants can grow in the alvars, especially the open pavement and shoreline alvars, quite fascinating. Pools of water collect in slight depressions in the surface of the rock ‘pavement’ after rain and spring snow melt, and then small amounts of silt and sand accumulate and provide a habitat for plants to take root in the shallow holes, grikes and joint fractures shaped by water erosion. The reason I found the alvars and the plants growing there so fascinating is that they remind me of a rock garden situation, a really though one, with little soil and rooting space for the plants, high temperatures in the summer and more than this with high variation on the moisture levels throughout the seasons.

Many of the alvar plant species are perennials, of which some are more or less confined to this particular environment. For example species like Cirsium hillii, Solidago ptarmicoides and Astragalus neglectus have a high alvar confinement (above 70%), while others like Zigadenus elegans have a low<50 % alvar confinement. Besides knowing and protecting them, the ability to grow in such conditions it is a proof of their adaptability and more of them should be tested into cultivation.

The following images have been taken in the Bruce Peninsula area, in Ontario – it is a gallery that gradually it will be updated with more species.