Wednesday, November 11, 2009

Petrocosmea 'Keystone's Harvest Moon' - A Petrocosmea For Autumn

Sometimes, one of the toughest things about hybridizing gesneriads is selecting a name for the hybrids. (the second toughest thing is the selection process where most of the seedlings to flower must be thrown into the garbage bin!) I was surprised a couple of years ago, while looking at a batch of hybrid Petrocosmea seedlings to note that one of them had leaves that were yellow...definately more yellow or golden than all of it's siblings. My first thought was that the plant was just chlorotic, so I repotted it and gave it a heatlthy dose of fertilizer. It only became more yellow! As the plant matured, I had removed some of the leaves to test whether the propagations from the leaf cutting would show the same trait. They do!

This seedling was eventually selected due to the unique trait of the golden yellow overlay of color on the leaves. I noted that various exposures to light produced slightly different degrees of intensity in the yellow coloration, but this plant always remained more yellow than all the other Pets. I suspect that it's parent, P. rosettifolia #3 which was used due to it's deep yellow veining in the leaves is the contributor to this trait. The flowers, being light lavendar, make a lovely color contrast to the yellow foliage.

So, what to name it? The yellow color appears to be overlaid upon the green leaves underneath, like the glow of a full moon upon an object, so I was inspired to name the plant 'Keystone's Harvest Moon'. The cross is P. rosettifolia #3 x sericea.

A young blooming plant of P. 'Keystone's Harvest Moon'. While the flowers are produced on long pedicels, a trait I normally wound have culled out in a seedling, the yellow pigmentation of the leaves promises the beginning of some interesting foliar characteristics if I can get the plant to hybridize. One of my goals for hybridizing Petrocosmea is to introduce new, more ornamental foliage, since often Pets are entered in shows as "non-flowering" entries.

A close up shot showing the lavendar flowers of P. 'Keystone's Harvest Moon'. This color makes a lovely contrast with the yellow foliage which can be seen in the background.

A photo showing P. 'Keystone's Harvest Moon' on the right, beside a young plant of P. menglienensis, to show the yellow foliage color of 'Keystone's Harvest Moon'. The plant is NOT chlorotic. I have tested it with a number of leaf propagated plants and all show the yellow leaf color even in various conditions. Light intensity tends to affect the degree of yellow coloration, with higher light producing the most intense yellow coloring.