Tillandsia cultivation.

[Derrick]

I will post this under a new heading so that the subject might remain compact.  Perhaps more skilled growers or those in different climates can add to these notes, except where items such as pollination syndromes are best added to posts regarding the specific species.

  Most of my tillandsias came from world wide exporter Andrew Flower at http://www.anwyl.com/ 

 

Tillandsia Cultivation.

The author's climate.  I will first provide a brief description of my local climate in the hope that it will provide useful background to my following cultivation comments. I live very near the cooler edge of the Southern Hemisphere subtropics close to the sea so my climate is very mild with maximum summer highs rarely above 25º C. and usually with only a few light frosts each winter which are becoming ever less frequent.  Our annual short days necessitate additional warmth for heat loving species; therefore, they are kept on heat mats in a bright sunroom that warms rapidly above outdoor ambient temperatures and does not get as cold. I have not grown many tillandsias here but NONE of them seem to require any additional heating if grown in my sunroom or glasshouses.  I also have a highland Nepenthes species growing quite successfully for two years under a small tree in my garden providing a useful indication of my climate.

In the absence of empirical studies known to me, I postulate that cultivation parameters such as thermostat settings may be varied somewhat around usually quoted minimums according to one’s own particular climate.  For example, if one’s local temperatures are rarely unsuitably cold such that they provide extensive periods of plant-amenable temperatures, then a somewhat lower minimum may be set, especially if the most cold sensitive plants are placed in one’s winter-warmest positions. One must observe the responses of one’s plants. 

 

Positioning. The most important consideration for all epiphytic ant-house plants including air-plant tillandsias is that although they are often xerophytic and sometimes succulent, they are very different to most terrestrial succulent plants that are often able to thrive in very low humidities.  Epiphytic ant-plants invariably require high humidity environments.  Extremely few species (if any) are suited to the correctly dry air of cacti aridariums.

We are concerned here primarily with ‘air plant’ or similar tillandsias; therefore, as long as they are cultivated with this in mind they are extremely easy to maintain in moderate climates.  Indeed, they are exceptionally hardy, requiring much less care than many other plants when positioned correctly. Although they are generally frost tender, warmer temperatures seem not at all as critical for tillandsias as they are for example with lowland tropical hydnophytinae and some tank bromeliads.  Acceptable temperatures range from a cosy 32°C (86°F) down to a cool 10°C (38°F). Indeed, many tillandsia s grow well in climates with summer highs not much above 25°C (75°F.)  Furthermore, they prefer mild overnight temperatures of around 15°C (60°F.)  Therefore, natural temperature ranges in warm-temperate climates should suffice as long as they have protection from combined cold and wet conditions. The colder it becomes, the drier they should be kept in winter.  It follows that tillandsias are far less energy consuming (in the fuel sense) than many other ant-plants.

  Filtered sunlight is best except in winter when at least some hours of direct, preferably morning sunlight that will assist warming in colder climes.  Also, consider that some ant-house tillandsias live in seasonally cool to cold deciduous forests where they endure stronger light in dry seasons. In suitably mild climates, they can be placed outside in warmer months, perhaps under a not too shady tree.  Positions that provide protection from excessive rainfalls will help, especially in cooler weather.  Indeed, in mild not overly wet climates, especially in positions with a sufficiently sunny aspect, they may survive outdoors for most or all of the year as some do in milder regions of New Zealand.

Tillandsias are particularly easy as houseplants but good airflow (if it is not too cold) is important.  Spare offsets can be used to test for best growing sites.

 

Potting/mounting.  These species are so easy to maintain mounted on timber or whatever slabs that a “potting” subtitle is unsuitable. Indeed, potting is almost invariably counterproductive for air plant tillandsias by entailing too much chance of rot. Those species that do grow naturally in soil (except canopy soil) are primarily beyond the scope of these notes.

 

Watering/Misting.  Mist one’s plants according to current warmth and humidity levels but be warned, leaves kept too wet for too long can suffocate and die. Conversely, do not leave them too dry for too long but for most mild climates this is of small concern. As always, watch plant responses to ones ministrations.

They will need none or little misting in the depths of cold humid overcast winters unless kept in the dry air of centrally heated homes.  Of course, they will need more moisture in any dangerously arid conditions with low humidities.

If possible, use lukewarm rainwater, which is naturally of the preferred slightly acid pH, hence avoiding alkalinity and tap-water contaminants.  If only tap water is available, let it stand open to the air for a few days to help pollutants to evaporate.

Plants using the CAM pathway (e.g. most if not all airplant tillandsias) and especially those originating from highland regions with cool to cold nights may have problems with overnight temperatures much above about 20⁰ C.

 

Feeding.  Some growers claim that air plant tillandsias do not require fertilisers, arguing they can get all they need from the atmosphere (indoors?).  This begs the question of why some species need their trophic associations with ants. Yes, they often occupy habitats with very low nutrient resources but they grow and flower better with suitably dilute repeat dilute levels of fertilising.

Unless one is sufficiently experienced, always mist-feed during growing seasons with perhaps a 25- 50% lesser dilution rate of a water-based orchid fertiliser as advised for indoor plants.  Indoor plants are expected to have slower growth rates due to a strong probability of decreased light levels within our homes.  One may gradually increase the frequency of applications and/or dilution rate according to overall husbandry regimes but most importantly follow your plant’s responses.  It is always important to observe how plants react to any changes in the parameters of our horticultural regimes and to adjust such administrations accordingly. They will need little to no feeding in winter.

Ensure there are no accumulations of fertiliser salts on or near these plants, something that does not happen in arboreal habitats.  Therefore, during suitably warm weather periodically flush them, preferably with tepid rainwater.  From information gleaned from expert epiphyte cultivators at Pukekura Park, New Plymouth, New Zealand.  Andrew Flower (2008) a knowledgeable New Zealand tillandsia cultivator, advises one should avoid using fertilisers containing Potassium chloride in their potting mixes and especially using it on plant leaves.  Potassium in its nitrate form is enormously safer to use with epiphytes but such formulations can be harder to obtain.

 

Resuscitating. Some growers have advocated submerging severely dehydrated ant-plants for hours to days at a time in order to resuscitate them.  It is possibly a dangerous practice; should there ever be an urgent need, never immerse more than perhaps half of a plant at any one time.  One never knows what unforeseen life events may preclude a timely rescue of fully submerged plants.

 

Cultivation hints from ecology. Studies undertaken in seasonally dry Neotropical forests, found that air plant bromeliads grow longer into the dry season than did phytotelm (water-impounding) species.  Local fogs and overnight dew events were very probably supporting this trend.  Conversely, phytotelm bromeliads grew mostly in the rainy season when overnight fog and dew events are of little benefit to them.

Furthermore, in seasonally dry forests, 40% of Bromeliad species were found in only 5% of tree species, most especially in those trees with compound leaves that permitted better light penetration.Indeed, and perhaps surprisingly, the importance of leaf type overrode that of bark type. (Reyes-Garcia et al. 2007.)There are very useful cultivation hints here; keep light levels optimum. Many other pertinent cultivation hints from ecological studies can be found under individual species.

 

Propagation. Tillandsia species are monocarpic; in other words individual shoots die after flowering and fruiting only once, but fortunately they produce anywhere from one to many more new shoots (offsets) either during flowering or up to some months later.  If so desired, offsets may be removed when sufficiently large (about one third to one half of parent size) and given individual growing positions.  They can be glued, e.g. no more nails®, wired, pinned, or tied to suitable supports with perhaps nylon fishing line. Offsets are of course identical clones. Offsets mature in only one to four years but unfortunately, tillandsia seedlings can take 7 to 8 or more years to mature.  Seeds are equipped with a coma (parachute like hair tufts for wind distribution) and it can take about a year for seed capsules to ripen on parent plants.

Somewhat compacted and flattened sphagnum moss is a suitable seed substrate.  Seed should be kept covered and moist until germination takes place - usually within a few weeks.  Flowering of adult bromeliads can be initiated with ethylene gas that is emitted by ripening fruits.  A simple way is to place plants in a plastic bag for a few days with one or more ripening apples that emit ethylene.