A Northumberland Alpine Gardener's Diary
This entry: 07 February 2010 by John Richards
A visit to Tenerife. Entry 138.
Winter lingers on
No diary entry for a month, partly because we are still firmly in the grip of winter (more snow forecast next week!) and little has moved. The earlier snowdrops have finally relented somewhat, and G. 'Straffan', G. 'James Backhouse' etc are nearly in full flower. But not even 'Three Ships' is fully out yet.
Another excuse is that we were in Tenerife for a fortnight. Should you say 'lucky them, escaping the frozen gloom', well, yes, but the holiday was not without incident. No sooner had we arrived than Sheila, and then I, went down with a nasty bout of norovirus. I shall spare you the grisly details, but suffice it to say that EVERYONE we met there, absolutely 100%, got it too, and it knocks you out of circulation for a good four days.
For the first ten days or so (while we were poorly!) the weather was acceptable, but we could scarcely leave our room for the last four days for violent electrical storms, torrential rain and gale force winds. Los Gigantes, where we were staying, received twice its annual rainfall in this period!
Poor us! Well, surprising as it might now seem, we did in fact get out quite a lot and got a fair impression of the mid winter flora. Despite being the highest mountain in Spain, which gathers a good deal of snow and ice, Teide is a very recent mountain rent by lava streams, some of which are only a few hundred years old. What little special flora it has developed is very dormant in winter, and there is little to see, but it is still an exciting and beautiful landscape.
Around the cone, as about 2200 m are outwash plains, known as 'Las Canadas'. It is here that what passes for an alpine flora grows.
In a ring round the mountain, between about 700 and 1800 m altitude, grows a Canary Pine forest in the protected 'Corona Forestal'. We would see very little in flower there in January.
Exceptionally, our storms came from the south, but usually most of the weather comes from the north-west, so that the north side of the island is much wetter than the rest, and is correspondingly rich. Of course, with 3700 m to play with, altitude has a huge effect, and in January we found little in flower above about 700 m.
I can think of few places where climate affects vegetation so markedly in a small area. In the deserts of the south, succulent euphorbias dominate, while in the spectacular, mountainous west there is an abundance of Crassulaceae-rich habitats. In the north the ancient laurel forest survives in places, together with abundant tree heather, while the richest habitats of all are found near the sea on northern cliffs, at Los Silos or El Fraile for instance, and there one can find a great concentration of rare endemics. With isolation and such a variety of habitats, it is not surprising that more than 1000 Canarian endemic plant species can be found on Tenerife. Many are very rare, and it is greatly to the credit of urban public spaces on the north coast at Pueto de la Cruz, Icod, Orotavo or Guarachico, that some are exclusively planted with endemics, often species that are gravely threatened in the wild.
Here are examples of a few of the major habitat types; firstly the cactus-like Euphorbia canariensis landscapes of the south.
Here are wet crassulaceae-dominated ciffs around the spectacular western village of Masca. The main Aeonium here is Ae. canariense. The second picture shows Greenovia dodrentalis, Ae. canariense and Monanthes pallens.
Here is the very local endemic Aeonium mascaense.
And the wonderful Ae. tabuliforme; the ultimate chasmophyte!
Go north from there and the vegetation changes abruptly. At Taibaiban we were delighted to find one of the very few native bulbs, Romulea grandiscapa.
Despite many recent volcanic upheavals, the flora of the Canary Islands is very ancient and is generally considered to represent that from the early Tertiary, perhaps 60 million years ago, which has been lost on the mainland through climatic catastrophes and competition from 'superior modern types'. There are four members of the laurel family, which, it has recently been revealed by the DNA, represent such an early offshoot of the flowering plants that they had evolved before the monocots and docots split.
Another feature, often thought to represent primitive features, is 'gigantism'. Familiar genera such as the sow-thistles, Sonchus, sea-lavenders, Limonium, and bugloss, Echium, are represented by massive woody types.
Here is Sheila walking through a lane that runs through laurel forest near Ruigomez. We christened this site 'Canarina lane', for reasons that become obvious in later pictures.
Canarina canariensis is a very primitive, vine-like member of the Campanulaceae, and was I think the plant I wanted to see above all others. In practice, it proved to be quite easy to encounter once one had spotted the right type of habitat, dominated not only by laurels, but also the two native hollies Ilex canariensis and I. platyphylla and the very lovely Arbutus canariensis.
Down to the sea-cliffs in the north now, with a view of Los Silos.
These cliffs are perhaps the best place to see examples of gigantism. Here is Echium giganteum (with an Indian Red Admiral butterfly), followed by Limonium arborescens and Sonchus congestus.
This is a good area to see some of the native cistus, C. symphytifolius and C. monspeliensis.
Nearly enough for today I think. I shall finish with two attractive crucifers from very different areas. Erysimum bicolor is a perennial subshrubby wallflower from northern sea-cliffs where it is common. Parolinia intermedia is much the rarer plant, but is locally common in a dry zone above the resort of Los Gigantes where we were staying.
Possibly more from Tenerife next time, unless spring arrives!