Most of what we know about cultivating Petrocosmea is still pretty new information. Many, or rather most, of the species we are growing now only arrived on our plant stands and show tables within the last decade. As we are growing them more, and our time spent with these plants is increasing, we're seeing for the first time in many cases, just what sort of peculiarities these wonderful Pets are capable of. Zippers, buttons and stolons are just three of the manifestations my Pets have produced in the last few years. Since these may be new to growers, exhibitors and judges of Petrocosmea, I thought I would discuss them in a short post.
The photo above is Dale Martens' photo of a "button" that appeared on her plant of my hybrid 'Keystone's Bantam'. There was a recently lengthy discussion on this phenomenon on Gesneriphiles, when a plant exhibited with such a button was marked down in judging . The judges, who were all expert and seasoned judged, had not encountered this anomaly before. One of them contacted me to ask if Pets "normally" did this. I've seen several plants of P. rosettifolia do this during the winter when I was resting them by keeping them drier than usual and cool. 'Keystone's Bantam' does this often, and since it is hybrid of P. rosettifolia, I suspect it inherited this trait from it's rosettifolia parent. I have also seen this once on P. forresttii.
In all cases, the plant produced a new whorl of leaves from the center of the "button" and the plant regained full and attractive symmetry within the rosette with the next cycle of growth.
Above is my photo of 'Keystone's Bantam' at it's first flowering. You can see the center button in the photo. The button appears to be a dense tuft of golden yellow hairs and does not represent poor culture or a rotted or diseased center. It appears to be a normal, although not that common feature of these plants. It is my opinion as a grower and judge that it should not be faulted or penalized in judging unless in the opinion of the judges, it detracts from the overall ornamental value of the plant. But, that's just my opinion...and opinions are like noses....everybody has one.
The next phenomenon in Petrocosmea growth patterns is what I call zippering or zippers. A healthy plant, usually with a few years of age, suddenly starts to produce a center growth point within the crown of the rosette, that begins elongate into a linear growth point. The normally circular rosette can often become more oval in shape, and if grown on, the plant often splits into two or three crowns. Eventually these will totally split or separate producing two or three new crowns. I see this occur often in P. forrestii, and it's hybrids, as well as the rosettifolias and their hybrids. I have seen it occur once in P. minor also. In all cases the plants were three years old or more when this happened. See the photo below of P. forresttii at five years of age, with a zippered crown, which eventually became three separate crowns. The plant flowered very heavily during this period. It appears to me to be more a factor of age that a cultural flaw.
Look closely at the plant in the center of the row on the left above....the one with the yellow ribbon. This photo shows a group of P. 'Short'nin' Bread' entries at a convention show a couple of years ago. The third place winner was a plant with a zippered crown..... it beat out some other specimens with more typical round crowns. This judges, in this case, did not penalize this plant for the zippered crown..... which again, they should not do unless it detracts from the ornamental value of the entry. Good judging in this case...as it demonstrates a panel of judges who were familiar with the habits of these plants. (P. 'Short'nin' Bread' is a P. forrestii hybrid...so it likely got this trait from its forrestii parentage.)
Stolons are yet another trait of healthy Petrocosmeas which we are seeing from time to time. I've seen it on several species and hybrids....so it appears to be possible on just about any Petrocosmea. I have not identified what might be triggering it other than the plant deciding that it wants to make some stolons.... I find it a "cute" phenomenon on most Pets.
Congratulations to B. J. Ohme of Perfect Petals for his first place winning entry of P. 'Short'nin' Bread' at the recent AVSA convention in Cherry Hill, NJ. Wisely, the judges recognized the additional ornamental interest that the stolons provided to this entry and gave B.J. his blue ribbon. P. 'Short'nin' Bread' is a plant that, in my opinion, is most ornamental when shown in bloom. But traits such as stolons can add ornamental interest. (Photo courtesy of Dale Martens..... "thanks, Dale!!!!!" )
So, there they are, the quirks that our Pets are capable of conjuring up to keep us fascinated and infatuated with them. These may be just the beginning of the wonders we will unlock as we enter into a new era of hybridizing with this genus.