Growing Tips for August 2000

by Courtney T. Hackney 

EMAIL at Hackneau@bellsouth.net

 

This summer has been a great one for Cattleyas in my greenhouse.  When most growers refer to this group they are including all intergenerics (BLC, LC, SLC, etc) as well.  What is obvious when all conditions are good is the variability among different hybrids with respect to vigor.  During spring repotting there are some plants that always provide a couple of extra divisions each time they are repotted, while other clones do not.  In the rush to produce bigger, flatter, more brilliantly colored flowers, plant vigor has become a secondary consideration.

When the primary purpose of a hybrid Cattleya was to produce flowers for the florist trade vigor, was most important.  Entire crosses were thrown away by nurseries before they bloomed because they did not grow well.  Indeed, most of the best are not plants with AOS awards behind their names.   Some are primary or near primary hybrids, but many are seedlings of modern hybrids.

There has been much speculation as to the cause of diminishing vigor in Cattleyas.  Ernest Hetherington who worked for Stewarts Orchids for many years thought that most plants had about a 15-year span before it died or lost its vigor.  Viruses and disease certainly claim many plants during that time, but theoretically, most Orchids have unlimited life spans.

            Each time a plant is repotted there are many injuries that provide an entrance point for disease.  Scale and other sucking insects may transport disease as well as sap the strength of the plant.  These are all potential problems, but the biggest problem is that we have forgotten how to grow Cattleyas.  Standard Cattleyas (those with large pseudobulbs and large flowers) need high light, lots of air movement, and a media that dries rapidly.  If your mini-catts are growing well, but not your standards it is because standards need different conditions than most growers give them.   Mini-catts require lower light and more constant moisture, an environment not ideal for standard Catts.

            One hundred years ago most Cattleya growers potted in Osmunda fiber.  Later, fir bark and mixtures of fir bark were used.  Tree fern was popular in hot climates and eventually every product imaginable was used to grow Cattleyas.  In most cases these new products were not adopted because Catts grew better, but because it was cheaper.  Commercial growers compensated by using more fertilizer of many different types.  Hobbyists are not always able to duplicate commercial conditions and so Catts do poorly.

            Some of the decline in interest has come from limited space in collections and the advent of space saving mini-catts, but a great deal is due to the inability of many to grow this group.  If you have been discouraged and want to try again, pick a few standard Cattleyas for their vigor.  The best source is a local grower with a division of a plant that grows and flowers well for them.  Use their exact technique if you can and see if you can grow and bloom this plant.  Periodically make side-by-side comparisons with the original plant.  Are your leaves darker?  Is your media breaking down more quickly?

 Once you succeed with one plant then get others, but always keep the good grower so that you can tell if poor growth of your Cattleyas is caused by your conditions or by the lack of plant vigor.  You may find that you prefer a plant that grows easily to one that has a better flower that you never get to see.