Question
QUESTION: Hi Wayne,

I'm experiencing problems with my oncidium hybrid: Wilsonara Tigersette 'Wild Court'. I purchased it last July while in bloom and now the pseudo bulbs have all shriveled up and the roots are mostly gone. The plant is almost half of what it was before, and without roots, can barely stabilize itself in the pot. There are clear signs of new green growth. It's been repotted several times due to root rot. It sits on top of a pebble tray, but my room is quite dry and it seems to not be growing new roots.

Are you familiar with this species of orchid? I've read countless care sheets, and found that this type needs more water than others. Should I just invest in another one or give this one another shot?

-Theo

ANSWER: Thanks for your interesting question Theo.  Wilsonara's are complex hybrids often created from several cool growing species.  Cultural advice generally include growing it under intermediate to cool conditions.  Night temperatures should be between 45-64 degrees F.  Daytime temperatures may be between 70 - 85 degrees on sunny days. I have found that some of the most beautiful flowers are produced under cool and bright conditions in the oncidium alliance-- conditions that may be difficult to achieve.  It may not been doing well because you have not been able to reprouce its ideal growing conditions.  I have flowered the hybrid that you have under high pressure sodium lights but found that it didn't grow well under these conditions because of the heat.  Care sheets are not always helpful with this type of hybrid because it is a mixture of cool and warm growing species and, depending upon the mixture of cool-growing vs warm growing species, one Wilsonara hybrid may be grown under warmer conditions than another.

Try brighter light and cooler temperatures if possible. Try to stabilize your plant in the pot.  Avoid growing it in too big of a pot-- just large enough to fit the plant. Humidity is good.  Let the potting mix dry out between waterings to reduce rooy rot (root rot almost always indicates that the root zone is being kept too wet. Growing it in a plastic pot will keep the root zone wetter and a caly pot will dry it our faster. A smaller pot also will tend to dry out faster.

If, after trying these tricks, you see no improvement, it may be that you don't have the right conditions for growing Wilsonaras. (However, I can understand the reluctance to avoid the challenge of another plant.)

---------- FOLLOW-UP ----------

QUESTION: Hi Wayne,

Thanks for the reply, it answered lots of questions and confirmed what I believed was needed for this plant: cooler temp, bright indirect light. The light levels it's receiving now are quite good, humidity level isn't where it should be, but I think acceptable. I can provide it cool nights, but daytime temps are probably higher than they should be.

I really like this breed of orchid, and I want to have a nice lush plant without the shriveled pseudo bulbs that I'm seeing now. There is new growth plant growth, but only a few new roots. It's in a very small plastic container with many holes. I'm using a non-urea, high nitrogen fertilizer, so hopefully that will help it along. However, due to it's lack of roots, I'm having difficulty finding ways to water this plant without moving the plant around in the mix. Should I dunk the whole plant into a bucket of water mixed with fertilizer? I know water shouldn't get inside the center of new leaves (as is true for phals).

In your opinion, other than phals, what's the easiest orchid to care for that can have multiple blooms each year?

-Theo

Answer
You should expect pseudobulb shriveling as the plant goes through it's rest period.  The new growth is a good sign.  I think dunking it is fine.  If you dunk it, however, be aware that fir bark might float up from the potting mix and out over the top of the pot.  It might be better to set the plant and pot in a shallow dish with a weak ferilizer solution and let the capillary action draw it up until the mix is thoroughly wet.  Then set it aside and let it drain for a  few hours and repeat this process only after the potting mix is dry.

I like cattleya alliance hybrids as they have large, fragrant blooms.  They do take up quite a bit of space, however, and need more light than phalaenopsis. Most go through a rest period when watering and feeding should be greatly reduced.  They summer out well.  In recent years breeding of cattleyas has concentrated on minicattleyas which are less tha 10 inches high.  Inital efforts in this breeding were not terribly successful becuase some of the species used were difficult to grow.  Now, more robust minicats are coming to market.  A prime breeder of these is Sunset Valley Orchids in California. If you select one of the older, full size cattleyas, choose those with the lavender or white flower color.  Yellow or red cattleyas use species that are more difficult to grow and that is passsed on to their hybrids.  On the other hand, this may have been overcome in the minicatts.