Contents of the Spring 2015 Northants News

Various plants share my greenhouse (and house window sills) with cacti and succulents; amongst them are some members of the Pineapple Family – the Bromeliaceae. In particular there are quite a few members of the genus Tillandsia, a large genus of more than 500 species. It was named by Carolus Linnaeus in honour of the Swedish physician and botanist Dr. Elias Tillandz (formerly Tillander) (b1640, d1693). The plants grow in the forests, mountains, and deserts of south and central America, also in the southern USA. The thinner-leafed, greener types grow in wetter, shadier areas, by contrast the thicker-leafed, greyer types in open areas more subject to drought. 

The grey-leaved Tillandsia species are generally lithophytes (growing on rocky substrates) or epiphytes (sometimes called aerophytes or air plants) growing attached to other plants. Their wiry roots are used for anchorage, not parasitism. Reproduction is by seeds or offsets. Moisture and nutrients (small detritus particles, decaying leaves and insect matter) are gathered from the air by hairs and via particular structures on the leaves called trichomes. See the detail in the views of T. bergeri and T. tectorum. (Below)

Although not generally cultivated for their flowers, some Tillandsia species bloom regularly, many with brightly-coloured small flowers. In addition particular species take on a different leaf colour when about to flower, usually changing from grey/green to red/purple: a commonly encountered species is T. brachycaulos. This is an indication that the plant is monocarpic (each rosette flowers once only before dying), but offsets around the flowering rosette will continue to thrive. Flowers can last from several days to some months and different species bloom at different times depending also on their environment and care regime. You can expect blooms at any time of the year.

Tillandsia ionantha is widely distributed in Central America, is easy to grow and my plant flowers every year; it was collected in Mexico by David Kirkbright and has formed a nice clump over a decade. By contrast Tillandsia bergeri from Argentina flowers less readily, but shows subtle shades of blues and pinks and is slightly fragrant. Many readers are familiar with the so-called ‘Spanish Moss’ which is neither Spanish nor a moss! Tillandsia usneoides adorns cliffs, trees, wires and other structures from southern USA to Argentina and is used ornamentally in many settings. I have two forms, one with brown flowers, the other with greenish flowers (see image on page 8). They make nice ornamental festoons in my greenhouse; if I hang them in one of my trees the birds think I have supplied them with a new source of nest-building material and they don’t last for long! 

Some species bear highly scented flowers, notably T. xiphioides, though in my experience this dwarf species from Argentina, Bolivia and Paraguay with its very hard leaves is not eager to flower. One particularly sought after species is T. xerographica, a Mexican species with large, striking rosettes of curled silver-grey leaves. It is on CITES Appendix-1 and is difficult to maintain in tip-top condition in a dwelling house.

To conclude I outline some cultivation points since Tillandsias grow very differently than most other house or greenhouse plants, so can be confusing to those unfamiliar with them.

•  They are mostly quite tough and require less attention than many other house plants.

•  Temperature is not very critical, a working range being from 35°C (95°F) down to 10°C (50°F).

• They are sensitive to frost, except for a few species including T. usneoides (the so-called ‘Spanish Moss’), which can tolerate night-time frosts down to about -10°C (14°F).

• Most prefer cooler night-time temperatures below 15°C (60°F).

• Give them bright, filtered light, the greyer leaved plants tolerate brighter   conditions.

•  Provided the atmosphere is not too dry (as in an air-conditioned home) they require relatively little watering or spraying, but remember Tillandsias cannot get replacement water from their roots like a terrestrial plant, or draw on internal reserves like a succulent.

•  If you grow them indoors and the air is dry, you should submerge the plants in water for 1-2 hours about every two weeks. After wetting your plants thoroughly, turn them upside down and gently shake them as water that collects near the base is detrimental if left to long. Otherwise, in a shade-house or unheated home, you can use a soaking mist once or twice a week in summer, once a month in cooler weather.

•  The water you use is important. Never used distilled water! Filtered water, tap water that has sat long enough for the chlorine to dissipate, and bottled water are all fine. Pond water, aquarium or rain water is preferred but tap water is better than no water.

•  Tillandsias will not survive in standing water.

• Fertilise them with a 10:8:15 NPK fertilizer (or orchid type) added to a mist sprayer.

• You can mount smaller, grey-leaved plants on cork bark using a waterproof adhesive or wires, but not copper wires. Trim dead leaves off older plants carefully.

•  Pests are rare, pick off any mealy bugs (they can be difficult to see on grey-leaved plants).

If you would like to try growing Tillandsias, do contact me for suggestions of suitable species and sources.

Roland

Useful Books:

‘Bromeliads for Home, Garden & Greenhouse’ by W Rauh [1979] Blandford Press ISBN 071370845X

‘Tillandsia’ by Paul T Isley III [1987] Botanical Press ISBN 0961767502

‘Growing Bromeliads’ by B E Williams & I Hodgson [1990] C Helm ISBN 0713680695

‘Schöne Tillandsien’ by E Gross [1992] Eugen Ulmer ISBN 3800165015 (German text)  

I expect you noticed that there were two mentions of Conservation Funds in our last issue of NN. The MSG auction and a print sold at the last BCSS Convention. I am sure these efforts contribute in some degree to a measure of protection for rare plants in habitat.

Having been lucky enough to have travelled a little in cactus and succulent habitats I am not optimistic about the long term future of our sort of plants in habitat. What is more, other greatly more experienced explorers feel the same.

Everywhere we go there is pressure from agriculture: irrigation from mountain reservoirs brings fertility for economic crops in coastal deserts. I saw the fertile but formerly very dry Vizcaino Desert plains of Baja California producing strawberries and oranges. Desert plants are quite edible to goats (and donkeys as we noted in Mexico). The internet shows us goats are being carefully bred to be more successful in even more marginal habitats. Where goats are grazed all vegetation up to several yards about the ground is eaten. Everything. Goats may even climb trees for the leaves. In these habitats only the most vertical cliffs are preserves for native plants.

Urban development also encroaches on natural habitats. As cities and towns expand the native plants disappear. (Though lawns may pop up.) I have been visiting the Mediterranean Costa Blanca in Spain over many decades, on and off. The historical vegetation, a mix of native plants, adapted to summer drought, and citrus and olive groves, has been largely replaced by holiday homes, bungalows, flats and huge apartments that look like stranded ocean liners. The urbanisation here creeps gradually up the mountains to engulf any remaining natural vegetation.

In Chile we saw massive mines everywhere, both opencast and underground, with huge spoil piles. I am not sure what plants were being threatened. These mines cannot be friendly for any local flora.  However along the coast we saw rocky bays being marked out and developed for the holiday homes of rich people. Unfortunate for the local Copiapoa populations; we saw Copiapoa calderana growing in someone’s garden near the beach.

Judging by the warning tsunami signs this is an area of potentially great danger; every 10, 20, or so years this area will be wiped out by a tsunami tidal wave. The 1960 earthquake was the most powerful ever recorded in the world, rating 9.5. The local tsunamis were up to 25m and entire coastal villages disappeared.   Maybe the people will not be on holiday here, or they might escape. The modern warning systems seem a good omen.  I suspect the cacti will probably survive a tsunami, if not as plants then as seeds to develop in the devastated landscape.

In Madagascar the news is just about all bad for conservation. The island is one of the major areas of succulent diversity in the world. We are told that the ‘Spiny Forest’, a unique biodiversity habitat, has almost gone. It has been burnt and the ground used for grazing. However new species of succulents are still being discovered in remote areas and particularly on cliffs. One wonders how long after the goats have eaten the remnants of the Spiny Forest they will be driven into these last reserves of plant diversity on the island.

Do I see any good news?

Well in Mexico, draconian laws protect the collection of native plants and seeds. I am not absolutely sure about the seeds, but very fair on the plants. Meanwhile the locals still dig up rare plants and offer them discretely to cactus tourists. And it seems that some bring back new species, (strictly illegally in Mexico) and then describe them as new species in Europe. (Strictly illegal in Europe, which also has conservation laws on the import of rare species.) Oh, well.

I visited several ‘National Parks’ in Mexico last year where beautiful canyons were marred by building sites for holiday homes for rich people. The properties had wonderful views just above any possible flooding levels of the river.

Perhaps America has the best policy. Large swathes of wilderness country, including areas of prime desert in the southwest are designated as National Parks. The policy is that nothing natural should be disturbed by the general public, (I saw a child admonished by a Ranger for picking up a stick), and that the Parks should be managed as carefully as possible to retain the natural habitat while increasing the convenience of the public to visit. This would usually be a mutually opposing view, when considering access roads and facilities. However in the Big Bend National Park I still saw excavation holes at a habitat for Ariocarpus fissuratus. So the National Park ethos of no disturbance cannot work where the rangers do not see.

I hope my general pessimism is not too infectious. A great many growers in the BCSS do not know very much about habitats. They are happy to grow these wonderful plants in their greenhouses, admire their shapes, then flower them and marvel at the colour and form. As I very much do. Good luck to them, I say.

But I do despair for our plants in habitat.

Trev