Summer had not yet begun and the mercury was already reaching new highs. Will this intense summer heat combined with the lack of water become the norm in Eastern Canada? Will we now have to plant more plants adapted to heat and drought in our gardens?
If you are one of those who believe that these extreme conditions are here for good, you will be happy to know that there are perennial cacti that work wonders in gardens without the need to provide them with a single drop of water. ‘water!
Of the four species of cacti growing wild in Canada, the prickly pear cactus is undoubtedly the most robust. Don’t be fooled by its name, since it grows up to 58° north latitude in Alberta, less than 8° from the Arctic Circle! Several colonies of prickly pear cactus can also be observed in the other Prairie provinces as well as in eastern Ontario.
Hold on to your hat, this is going to blow your mind! Scientists have determined that, in its natural environment, the fragile prickly pear cactus can withstand temperatures down to -50°C. In addition, they subjected theOpuntia fragilis at a temperature of -70°C and immersion in liquid nitrogen at -196°C following slow freezing down to -40°C. As a result of this absolutely extreme treatment, 50% of the prickly pear stems survived! Incredible but true! For its part, theOpuntia polyacantha withstands around -40°C, while the eastern prickly pear cactus and viviparous escobaria, two other cactus species native to Canada, survive temperatures around -35°C.
The cacti presented in this column are very undemanding plants which can be planted in the majority of flower beds. As long as we provide them with well-drained soil – made up of two thirds sand and one third compost – and plant them in full sun, these plants can create very original and distinctive arrangements. We can therefore, without fear, plant these friendly cacti in a flowerbed alongside tropical-looking perennials and annuals. And the most wonderful thing is that there is no maintenance to be given to them; you just have to let the rain and sun do the work!
Here is the list of the three perennial cacti most resistant to extreme climatic conditions in Quebec.
Oponce fragile
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Height: 10 cm
Width: 80 cm
Bloom: yellow in July and August
Sunshine: soleil
Hardiness: zone 1
The fragile cactus is undoubtedly the most cold-resistant cactus there is! This cactus is rather atypical for an opuntia since it produces spherical stems and not flattened as is the case with most other species. Its stems form a dense carpet over time and bear pretty yellow flowers during the summer. There is also a variety of fragile cactus without needles, called potato cactus.
Eastern prickly pear
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Height: 20 cm
Width: 80 cm
Bloom: yellow in July and August
Sunshine: soleil
Hardiness: zone 3b
The Eastern prickly pear cactus is a perfectly hardy cactus in our climate. In fact, if it is well covered with snow during the winter period, this pretty cactus with yellow flowers resists temperatures around -35°C quite easily. However, when spring comes, its stems are brown and shriveled. It generally takes a few weeks for it to regain its normal color and appearance.
Viviparous Escobaria
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Height: 5 cm
Width: 30 cm
Bloom: pink in July and August
Sunshine: soleil
Hardiness: zone 3b
This species is commonly called a ball cactus. In addition to its great resistance to cold, this spherical cactus is very pretty at the beginning of summer when it is covered with large pink flowers.
