Snow covered cacti on the balcony

Escobaria vivipara with a light snow cover

I’m fascinated by the ability of certain cacti species to survive even quite extreme freezing conditions. A fascination that is probably rooted in my childhood belief that all cacti were heat craving desert dwellers that would succumb to subfreezing temperatures - great was my surprise the first time I saw pictures of a cactus covered in snow.


Echinocereus triglochidiatus var. mojavensis sprinkled with snow

I live in a condominium and the only possibility for pursuing my interest in growing frost tolerant cacti outdoors - apart from the bed of winter-hardy cacti at my summerhouse - is to grow cacti in flower boxes on the balcony.

For several years I have successfully grown Echinocereus triglochidiatus (claret cup hedgehog cactus) outdoors (year-round) at my summerhouse in the northwestern part of Denmark - inspired by this I acquired a few E. triglochidiatus var. mojavensis (DJF1273; North of Inyo County, California) plants for my flower boxes a couple of years ago and they are also doing great.


Escobaria missouriensis in the snow

The well-being of the Escobaria species are of greater concern to me. The Botanical Garden of Copenhagen attempted growing Escobaria in their outdoor cactus bed but they all perished. My plants still seem to be weathering it out here in Copenhagen but I’m concerned that the continuous frost-thaw cycles will expose the plants to killing moisture.

Denmark has been frost-bound for several weeks now with the plants seeing temperatures as low as -10 C (14 F) (this is nothing for Escobaria vivipara which is known to have survived extreme temperatures as low as -35 degrees C) but the frost now loosens its grip again and it has started to rain, soaking the flower boxes that are still frozen solid. I hope that the light shelter provided by the balcony on the floor above will keep the plants from getting too wet - if not, I reckon the rot will soon show in the coming period of relatively warm and humid weather.

The beehive cactus species I’m growing in flower boxes on the balcony are Escobaria vivipara (Alberta, Canada) and Escobaria missouriensis (Mesa County, Colorado; SB204)


Flower box with Escobaria and Echinocereus cacti in the snow

This coming season I plan to grow peyote cactus in outdoor window boxes as well - but I don’t expect peyote to cope well with the Danish winter so the plants will need to be wintered in the attic.

Below are a few pictures of the balcony grown Escobaria plants during summer - what a happy flowering bunch :-)


Flowering Escobaria vivipara (Alberta, Canada)


Flowering Escobaria missouriensis (Mesa County, Colorado; SB204)

In relation to the two above images, the previous post featured a high-speed video showing the flower fly hovering above the Escobaria vivipara cactus.

Hoverfly visiting a flowering Escobaria vivipara (Alberta, Canada) cactus

While preparing a post on the cold-hardy cacti I'm growing in flower boxes on my balcony I stumbled upon this high-speed video I shot last summer. The video shows a hoverfly visiting a flowering Escobaria vivipara (Alberta, Canada).


Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae - a group of superbly beneficial insects, the adults being pollinators and the hoverfly larvae being predators of aphids and other damaging insect pests and their larvae. The coloring and movements of most species mimic bees or wasps giving them some protection against being eaten by birds.

I’m by no means an entomologist and to my untrained eye the flower fly in the video looks like a Scaeva selenitica (a common European species of hoverfly) with its three pairs of yellow comma markings on the abdomen. If you are an expert on insects and recognize the fly I would be happy to know the exact species.

If the above video doesn’t embed properly you can open it in a separate window by clicking the image below.


Hoverfly (Scaeva selenitica?) visiting flowering Escobaria vivipara (Alberta, Canada)

The high-speed video was filmed at the end of June 2012 using a Nikon 1 J1 camera.

The killing frost – life goes on

As mentioned in two previous posts (available here and here) this winter was extremely cold and killed off large parts of the collection I grow in an unheated greenhouse. Now spring is comming and the surviving plants are getting ready to move on.


Lophophora williamsii var. echinata with fruit

Most of my Trans-Pecos peyote plants (Pecos River area, Val Verde County, Texas; JJH 8608293) made it through the winter and is now setting fruit as if to herald the beginning of the comming growing season. If you look closely you’ll even notice a few flower buds.


Trans-Pecos peyote with budding flower

The Trans-Pecos peyote is also known as Lophophora williamsii var. echinata and is more cold-hardy than other varieties of L. williamsii

My Epithelantha micromeris plants (near Belen, New Mexico; SB1327) are also busy securing the next generation.


Epithelantha micromeris with fruit, top view

I’m getting increasingly infatuated with Epithelantha - you can’t but love the complex spination and the almost shocking pink fruits ;-) As Epithelantha has also proven to be an extremely cold hardy genus I’ll probably add more of these plants to my collection in the future.


Epithelantha micromeris with fruit

I am growing these plants at my summerhouse and not seeing them as often as I could wish. Unfortunately this also means that I miss a lot of the flowers including those of the Normanbokea valdeziana and Acharagma roseana pictured below.


Normanbokea valdeziana about to flower


Acharagma roseana about to flower

Fortunately fruits are more persistent than flowers giving me the opportunity to enjoy sights like the orange-red berries of Escobaria missouriensis (Mesa County, Colorado; SB204)


Escobaria missouriensis with fruit

My Maihuenia patagonica are thriving after the winter but not exactly flowering or setting fruit. I don’t have much experience growing Maihuenia - I originally fell for Maihuenia poeppigii but being a completist I ordered M. patagonica seeds as well. All the M. poeppigii plants succumbed to the frost this winter while the M. patagonica plants only suffered a few casualties. I'm not sure I’m treating the plants right, though, as they are growing strangely lanky, far from the dense, clustering habit I have seen in pictures (and the plants are getting plenty of light).


Maihuenia patagonica

And now for something completely different.

My summerhouse is located on the west coast of Denmark overlooking the North Sea. This weekend the Sun set in a sky looking much more orange than usual, and slightly diffused as by a thin haze.


The Sun setting in a haze of ashes from the Eyjafjallajökull eruptions

I take this to be caused by the Eyjafjallajökull volcano eruptions that have been sending a vast, invisible plume of grit drifting over Europe and kept most of European airspace shut down for several days. Of course one could imagine that a sunset like this was caused by a thin layer of clouds, but I have enjoyed hundreds of sunsets from my terrace and never seen anything like this before.


Sunset with a diffuse halo of refracted light – probably caused by Eyjafjallajökull ashes

On a different note, the Eyjafjallajökull volcano eruptions almost got me stuck in Amsterdam (not the worst place to be stuck in, by any means ;-) I and a colleague were supposed to have flown home in the late evening of April 15, 2010 – but as we watched more and more flights getting canceled and increasing parts of the north-western European airspace being closed down we agreed to rent a car. So in the early afternoon we set out on a long drive home – which in hindsight was an extremely wise decision as Danish airspace is only opening again today ;-)