I'm trying to determine a steadfast rule-of-thumb for when a sempervivum seedling can be effectively selected for/against.
I know that there's been discussions on this before, but I'd like to sum up that discussion and propose a solution to this slippery topic, either validated or invalidated by our more experienced hybridizers.
So far we've determined that young seedlings (under 1 year) are in a state of constant change, and throwing out unattractive plants at that stage is likely to lead to the elimination of potentially optimal candidates. However the question of whether it is appropriate to toss out seedlings in the following two years is largely contingent on the level of maturity the seedlings have reached in that time. A multitude of factors such as soil, nutrients, light exposure, and competition from siblings can drastically affect the growth and maturation of seedlings over a given time. Those which experience unfavorable conditions become dwarfed by comparison to their healthier siblings, but this is not an effective test of a seedlings genetic merit.
It's been said that in a well grown crop, early selections can be made at the beginning of the second year, but also that the other seedlings should be left over for another year to continue to develop. But what about seedlings that appear to be developed enough to select, but aren't showing promising colors?
To someone with limited space such as myself, it'd be advantageous to be able to spot unworthy plants as early as I can ensure that they aren't worth keeping. So in hopes of determining a means of deciphering the good seedlings from the bad early on, my question is this; can size be used to determine whether a plant is showing mature coloration?
If so, the size of the seedling relative to the size of the parent plants could be the key to weeding out the bad plants early on. For instance, 'Glauca Minor' is a medium sized plant, it tops out at about 4" in diameter, but the color of the rosettes doesn't change much between two and four inches. Of course there may be some variation in the size potential between the offspring and the parents, especially if one parent is much larger or smaller than the other, but wouldn't one be able to expect a 'Glauca Minor' seedling measuring two or three inches to be displaying it's mature colors? Especially if it's other parent was the same size or smaller.
This could save the process of selection a step. If I could open up some space in my year-and-a-half old seedling beds by selecting against unwanted colors, I could have more opportunity to focus on growth habits over the next year rather than leaving things clustered too tightly to be able to see how the colony's might form.
Lynn, I know you've seen dramatic color changes in seedlings between the first few early years. Did the color shift in your green seedling that turned black happen in conjunction with an increase in size, or did it reach it's maximum size before the color shift? Furthermore, is the black coloration seasonal or does it remain that way (or nearly so) all year?
Kevin, it would be helpful to hear your perspective on this.
Julia, have you noticed seedlings reaching 50-75% of their maximum size still not showing mature coloration?
Jo Ann, I recall a story of you discovering gems in your "to toss" pile, do you think it was just spring magic bringing out the colors, or had they gone through a spring at that size before?
Trying to find a ways of separating the wheat from the chaff. So far I've removed anything that seemed rot prone and was otherwise uninteresting but I'd like to cut deeper, preferably without pitching anything that could have been worth keeping.
At 16 months old, some of the seedlings have looked impressive for a long time, others have just gotten my attention in the last few months, some never looked good and continue not to despite growing rather large.
