Pollinating the Vanilla Flower
When we learned from our first book on orchids that Vanilla is an orchid, we thought it would be nice to have one, and when our green-house was up a year later, a piece of Vanilla vine was one of our first acquisitions. We were happy when it started to grow, but since it would be a long time before it was big enough and old enough to flower, it was moved from time to time to where it wouldn't be in the way of plants that were expected to flower. Eventually it became so tall that there was only one place in the greenhouse with sufficient headroom for it, and there it stayed, in an intermediate section where the night temperature is kept at 60 - 62F. (I am giving this history to explain that it probably wouldn't normally take the seven years it took us to get it to bloom.) We didn't know then if it could be bloomed at all in a greenhouse in our area. There has been very little mention of Vanilla in the AOS Bulletin since we began receiving it, nearly eight years ago.
Vanilla planifolia, the commercial
Several times in the past few years we thought we had a flower, but it was only a new growth, so this year when a knob started to form at one end, about the third week in March, we didn't get excited until a definite ring of buds had formed around it. We looked over the vine and found two more of these clusters, and by early May it was apparent that each one would have from 16 - 20 flower buds. The first flower opened on May l1th. It was yellow-green, more like an Easter lily in shape (though about one-quarter that size) with a nicely fringed lip and petals of good substance. Blooming time is similar to that of daylilies. Each flower opens for a day, but each day new flowers open and this continues for a period of six weeks to two months or more. The continuing bloom gives time for trial and error in the effort to pollinate the flowers for Vanilla beans. No doubt the insect which does the job in nature needs this multiple opportunity almost as much as I did.
I had successfully pollinated some Cattleyas, but I knew from Mrs. Rebecca Northen's book. Home Orchid Growing, that there is a gimmick to pollinating Vanilla flowers. Quoting from her book - "Hand pollination was a mystery. Placing the pollen on what appeared to be the stigma produced no results. Finally, a Creole worker discovered that the stigma was covered by a shield, which had to be lifted in order to place the pollen on the stigma. After pollination, the shield snaps back into place."< /P>p>With this information in mind I commenced the operation. I found that the column was attached to the lip on both sides of the column and it was impossible to lift the anther and remove the pollen without tearing the lip. There is a tiny cap underneath the anther which can be raised. Assuming that this must be the shield, I placed the pollen (which was anything but adhesive) underneath the cap and pressed it back into place. There is nothing snappy about a Vanilla flower./p>
The following day my treated flower fell off. With a Cattleya flower that means the operation was not successful, but maybe a Vanilla flower is different? In a few days the stem fell off too! Flowers which had not been treated also fell off the second day.
I went through my eight years of BULLETINS; I wrote letters to possible sources of information; I tried to think what an insect would do. Short of telephoning long distance to one of Mrs. Northen's workers, I was stuck.
I kept tearing fallen flowers apart and found that the front of the column can he peeled down with the thumbnail, exposing a ridge in the column. Placing the pollen on this ridge and pushing the peeled section back in place was my next try. By June 4th I thought I had a "take." A flower had stayed on four days and was quite brown. The stem had elongated and was hanging down in contrast to the other stems, which pointed upward. This may have been accidental, but after a few more tries I adopted the following process.
Push up the anther and remove pollinia. Press the yellow pollen mass out and hold it firmly with the right thumb and right index finger so it won't fall off. With the right middle finger push the anther back to raise the cap underneath it. Then with the left thumbnail peel down the front of the column about one-quarter of an inch. With the right thumb and index finger place pollen on ridge, push peeling back in place with left hand and cap down on top of it with right hand. By the second day the stem turns downward and begins to elongate. Flowers do not fall off, but wither to dark brown. The best time of day to pollinate seemed to be between 11 a.m. and 12 noon. Earlier in the day the pollen was less ripened and very hard to handle or place on the column.
I would still like to know how an insect accomplishes the job. and also how long the bean should be left on the vine, so would welcome further discussion of the subject. - Falls Village, Connecticut.
Click here for a gallery of hand-pollination images