Orchid Growing Information > Promenaeas

Promenaeas

Promenaeas are a little researched group of small plants that grow naturally on trees in the elevated rainforests of Brazil's south eastern states. Depending on which book you read there could be as few as eight species or more than twenty. Most species and hybrids flower during the summer months although the duration of the flowering season could easily be extended by some astute hybridising.

The main species available in this country include:

  • P. stapelioides
  • P. xanthina
  • P. rollisonii ( often incorrectly labelled as P. rollinsinii but the extra 'n' is errant as it appears that this species was named after Rollison's nursery in England)
  • P. ovatiloba ( another troubled name as it is proposed by some authors that it should be ovatilabia to reflect the prominent oval labellum)
  • P. guttata

To this list may be added the following 'possible' species that appear from time to time:

  • P. paulensis The few clones of this 'possible' species that I have seen are similar to P. xanthina but they flower at the end of winter, have much fuller flowers and have erect racemes. These clones were imported by Easy Orchids ( Woodburn N.S.W.) and only a limited number were available after the quarantine process.
  • P. riograndensis The photograph of this 'possible' species that appears in the book Orchids Of Brazil and the one plant I have show the flower to be white with pink spotting. The plant I have self pollinates as it opens resulting in the flower segments fading and closing giving a false impression of a white flower. I suspect that this 'species' is probably part of the P. rollisonii complex.
  • P. williamsonii The only plants of this 'possible' species originated from Florafest Nursery at Toowoomba . Ultimately the nursery marketed it as a form of P rollisonii which, I feel, is a more accurate label.
  • P. shuttleworthii Sydney grower Kevin Wilson has the only plant of this that I an aware of. He procured it as a swap from another grower and as it is a little tardy to grow it has not flowered yet - a real mystery!

Many species names appear in a variety of sources and, unfortunately, are unknown to me. They must either be very rare (in Australia and / or Brazil) or considered as not worthy of cultivation in a land that is home to orchids such as cattleyas that have more conspicuous plants and flowers. Perhaps these names appear due to some backyard botany or sloppy taxonomy.The unknown Promenaeas listed on the 'Orchidmania' website are - acuminata, albescens, catharinensis, dusenii, fuerstenbergiana, lentignosa, malmquistiana, microptera and paranaensis.

Culture

Promenaeas are very forgiving little plants that, given suitable conditions, will rapidly develop into specimen plants. A 100mm. Potful could easily produce over thirty relatively large blooms.

Generally if you can grow Zygopetalums well you should grow Promenaeas to perfection. The only cultural requirement that they seem to be fussy about is their need for heavy shade. They are tolerant of a wide range of temperatures but are stressed by extreme heat ( withering rapidly if left dry) and exteme cold( leaf dropping and spotting) especially if not kept under cover. I can grow them in Sydney both in a glasshouse, heated to a minimum of 10 degrees celsius, or outside year-round under cover. The ones in the shadehouse grow best in summer while the ones in the glasshouse grow best in winter. Keeping the foliage dry on winter nights, as you would for most other genera, seems to be more important than temperature.

Promenaeas will grow in almost any medium provided that it is airy and retains some moisture. Most growers seem to use either pine bark, sphagnum moss and styrofoam, pine bark and pebbles or a combination of these. I use fine treated pine bark (70%) and fine pebbles to which I add a small amount of chopped sphagnum and fine styrofoam. Depending on your conditions and watering regime you could improve your culture by using a layer of medium grade bark in the bottom of your pots to speed the drainage for wet climates and heavy waterers. Alternately you can 'top-off' the last centimetre of your pots with sphagnum to retain a little more moisture for those in dry areas or who are miserly waterers.

Promenaeas respond well to fertilizer when they are in active growth. Most liquid fertilizers on the market give good results provided that they are applied as a weak solution. I do not pot in straight sphagnum but most of the growers that I know who do seem to avoid organic fertilizers and prefer to use very weak chemical fertilizer .

Promenaeas prefer not to be allowed to dry out for long periods so regular watering is the order of the day. I like to see the green bulbs begin to wrinkle a little before I apply more water. Like most other orchids too little water is far less harmful than too much . A well grown Prom. hybrid should flower in a 50 mm. tube in the second summer after leaving the flask, some will flower even sooner while species could be expected to be a little slower. It would be prudent to keep water away from the new growths as they form to discourage rot - as you would with any other orchid.

The soft leaves and relatively large juicy buds and flowers are very attractive to grubs, slugs and snails but otherwise they are relatively pest and disease free. An unusual feature of Promenaeas is that once a flower has been pollinated the flower fades but remains alive during gestation. This makes your precious seed capsule even more appetising to those crawling nasties.

Hybrid Development

Interest in this genus has increased over recent years and this is reflected in the number of hybrids that have been registered during this time. The following list reveals that a relatively small number of species have been used in the background of these hybrids. This probably reflects limited availability rather than an absence of horticultural merit.

Promenaea Hybrids

  • Prom. Cachaca = Prom. Norman Gaunt x Prom. Florafest Cheetah
  • Prom. Carnival = Prom. Galaxy x Prom. Dinah Albright
  • Prom. Catarina = Prom. Crawshayana x Prom. Dinah Albright
  • Prom. Chameleon = Prom. Limelight x Prom. gutttata
  • Prom. Colmaniana = Prom. Crawshayana x Prom. xanthina
  • Prom. Crawshayana = Prom. stapelioides x Prom. xanthina
  • Prom. Dinah Albright = Prom. stapelioides x Prom. Norman Gaunt
  • Prom. Firefly = Prom. ovatiloba x Prom. guttata
  • Prom. Florafest Cheetah = Prom. Samsu x Prom. stapelioides
  • Prom. Florafest Gold = Prom. xanthina x Prom. Samsu
  • Prom. Florafest Sparkler = Prom. Colmaniana x Prom. Samsu
  • Prom. Galaxy = Prom. Rollisonii x Prom. stapelioides
  • Prom. Goldspeck = Prom. Xanthina x Prom. Norman gaunt
  • Prom. Kiwi Small World = Prom. Crawshayana x Prom. Norman Gaunt
  • Prom. Limelight = Prom. stapelioides x Prom. ovatiloba
  • Prom. Meadow Gold = Prom. Limelight x Prom. Xanthina
  • Prom. Michael Wilson =Prom. Dinah Albright x Prom. stapelioides
  • Prom. Norman Gaunt = Prom. stapelioides x Prom. Crawshayana
  • Prom. Olinda = Prom. Norman Gaunt x Prom. Dinah Albright
  • Prom. Samsu = Prom. Crawshayana x Prom. Rollisonii
  • Prom. Winelight = Prom. Limelight x Prom. stapelioides

These commonly used species along with those yet to be used in breeding and their potential contribution to a breeding program are outlined in the following table.

Promenaea Species Desirable Potential Attribute

xanthina

Strong yellow colour
Ease of culture
Floriferous, can have more than one flower per raceme

stapelioides

Almost black labellum
Large flower
Bold purple markings on a green background
'Full' round flowers

rollisonii

Fine spotting on petals
Last to flower - extend the flowering season well into the new year
Ease of culture

ovatiloba

Clear pale yellow
Large, but open, flowers
Prominent labellum

guttata

Brown barring on a yellow background
Prominent gold labellum
Floriferous , can have more than one flower per raceme

paulensis

Erect raceme
Strong yellow colour
Broad petals
First to flower - could extend the flowering season into spring

Neville Roper