Back at work.....

Greetings! One never knows what life is going to toss at us. The last couple of months have been a bit tough with an unexpected illness and surgery. Three hospital stays and a few weeks to recover and everything is fine now...things seem back on track. The past couple of weeks have seen me able to get back among the beloved Petrocosmeas....I've missed them~! But, as they always do, they banished my duldrums with the annual start of the flowering season. The earliest to bloom for me, P. formosa, was in all of her glory when I made my first visit back to the basement plantroom. What a welcome!

While P. formosa most typically blooms in pale orchid purple, a fellow Petrocosmea enthusiast in New York gave me a peek at his white P. formosa. Not sure where he acquired the plant, he did not recall it being given to him as a white form...however, that's what it has produced for the past couple of seasons now. He observes that the flowers remain pure white with the typical yellow base to the upper corolla lobes. I did note, that the yellow blotch in this form is more lemon yellow whereas the yellow blotch in the typical purple form that I grow is more orange-yellow. I have a large leaf form and a small leaf form and both produce purple flowers with orange-yellow blotches. I'm hoping this one remains white.... a lovely flower it was indeed!

Getting back to the Petrocosmeas just as they are producing this years flush of growth made me restless to get things groomed, repotted and "back in order". This photo shows an assortment of species Petrocosmeas in the matt-lined trays in which I grow them. The larger plants in the foreground are in 5 inch pan pots and are a couple of years old now. They were groomed of old outer leaves, the top quarter inch or so of soil was gently washed away and they were top dressed with systemic insecticide granules and fresh soil mix. The mats were washed in hot water, detergent and bleach and repositioned in the bottom of the trays, where they were dampened to provide humidity. These mats are cheap acrylic blankets cut into 22x22" sections, folded once to make a double thickness to line the 11x22" nursery trays. As the plants come into bud in the fall, the trays are covered with a plastic humidity dome to increase the humidity for the flowers....which aids is successfull pollination when I hybridize them. Last the plants were watered in with dilute fertilize water. And, for good measure, I told them how beautiful they were and encouraged them to grow up to be big and strong....

I've often been asked "How do you find new Petrocosmeas?" Admittedly, they can be a challenge to find. I am very fortunate to have great plant friends who know my love for the genus, and when the acquire new selections, the share them with me. The box above was a generous gift from a dear Canadian friend who brought them across the border to me last March when I attended the Buffalo, New York gesneriad and violet show. The included a new unidentified species labeled P. sp. 'Chinese #3' and a new form of P. rosettifolia with nice bluish lavendar flowers...(this made my fifth form of P. rosettifolia...all distinctly different from each other, but all clearly, the same species.....of course DNA analysis helped me to prove that!) How exciting to have five forms of the same Petrocosmea species! So, my advice to those wanting to build a collection is to get the word out to all of your plant friends......Gesneriad lovers are among the most generous people in the world!

Once home, I dutifully put down leaves from each of the new Petrocosmeas in the box above, partly as insurance again loss, and partly to be able to distribute them to others. That is one of the best nuggets of advice I ever got from a wise gesneriad grower.....Whenver acquiring a new gesneriad...PROPAGATE IT!!! That has saved me from losing a precious new acquisition so many times!

It feels good to be back. I'll do my best to post to the blog more often now!

Bloom Potential for Petrocosmea and "How Do I Get Them To Bloom?"

What can we expect from a Petrocosmea when it flowers? How much bloom is the plant capable of? When we look at a Petrocosmea entered in a flower show in bloom, how do we assess if the plant is meeting it's potential for bloom? As an admirer of this fascinating genus, and as both and exhibitor and Master judge for the Gesneriad Society, I am often faced with these questions. When I give a presentation on Petrocosmea, I am often asked how to "make them bloom". So for the past couple of years, I've done a bit of personal research and study on my own plants to assess just what it takes to get the plants to bloom at their full potential. I thought I would share my findings and thoughts with you here.



The plant in the photograph above is Petrocosmea grandiflora (or duclouxii, or floribunda...depending upon the source you obtained your plant from...genetically, they are all turning out to be the same species). This plant is my own plant, and the photo was taken this past January, as one all five of my mature plants of this species came into flower. This one is typical of those that I grew in the basement, in rather cold conditions, with humidity between 45 and 70%. The plant is in a 5" pan pot, where it has now been for four years. I have only top dressed the plant with new soil...it has not been repotted in that time. Starting in August, this plant was given plain water, only watered about once a month, and kept rather dry in between these monthly waterings. At times, the soil dried to the point that the leaves wilted a bit. Temperatures in December and January were as low as 35 degrees F and and as high as 52 degrees F. This is it's bloom potential under these conditions. Other plants of this same species, of the same age, in the same potting mix and pot size, that were kept warmer, and given more frequent waterings, (one was wicked on a reservior of dilute fertilizer water) all flowered significantly less than this one. The plant on the reserviour of water had less than half as many flowers, but did have more leaves on the rosette.



So this is what I got with the cold, dry, humid, and no fertilizer treatment described above. Other species given identical treatment all flowered heavily. They are pictured below.....

Petrocosmea minor smooth leaf form was also kept cold, dry and humid. This is the most this plant has ever flowered for me in several years. This species does not appear to flower heavily at one time, but instead seems to flower over a longer period of time, with a few flowers open at one time. This plant is also in a 5" pot and has been there for three years now without repotting.

The above photo is a showplant, a first place winner, grown by the master gesneriad grower Bev Williams of Canada. Her plants are always grown and shown at full potential. The plant is a lavendar flowered from of Petrocosmea rosettifolia. This species always seems to put flowers out along the outer edge of the rosette, rather than clustering the flowers toward the center of the rosette as some species do. Note the flowers here....when entered in bloom, this is what an exhibitor or judge of Petrocosmea should consider in deciding on the points value of "Quantity of Bloom". Many Petrocosmeas entered into shows here in the USA in flower are in my opinion, entered as either immature plants or they have been grown in such a manner that full bloom potential is not acheived. Often Pets in shows have four or five flowers and they score pretty high on the "Quantity of Bloom" section of the score sheet. This is something that judges should begin to consider and "adjust" when the evaluate Petrocosmeas entered in bloom.....again, just my opinion........

A mature but rather small plant of Petrocosmea sp. 'China 2005' in it's third year in a 3 1/2" pot. This plant was also given the cold, dry, humid, plain water treatment described above, and flowered much better this year than ever before. This plant stays much smaller at maturity than other species, so I grow it in a smaller pot. It's bloom potential makes it a great candidate for hybridizing with the goal of producing hybrids with more bloom potential. Cold and dry seems to to the trick with this one too!

A blooming plant of Petrocosmea sp. 'Yumebutai'. I've only had this plant for three years, and it has remained in a 4" pot since I got it...never repotted. When this plant was given to me, the grower said that he'd never been able to flower it. I've also heard this about this species from one other grower. The plant did not flower for me last year, when it was grown warmer and watered more often. But, this year, the cold, dry, and humid treatment worked well. This photo was taken in early February of this year.

SO, what factors worked best for me? Well, the cold is definitely a positive factor in at least increasing the flower count. I've heard from a correspondent in China, who has seen Pets growing in habitat many times, that the plants often experience short periods where they are covered with snow. My basement gets down to the mid-30's F range. Now, I realize that most growers who grow in the living areas of their homes cannot allow the temperatures to get down into the 30's.... but I'm just saying that it definitely helped in my research. Yes, plants in the warmer areas did flower...just not nearly as much as those in the basement where it was cold.

Secondly, plain water helped. The rationale I used for this is that fertilizers might be forcing more foliage growth at the expense of flower buds. Maybe so, or maybe not. But that was a factor in my experiment and those plants did seem to have more flowers and smaller rosettes. I began with the plain water when the plants were beginning to form buds.

Third, high humidity. I feel this helps the buds to mature and not to blast. In the warmer areas, with more heat, the humidity was lower. I occasionally did see a loss of some flower buds in that situation. But, then I advocate high humidity for Petrocosmeas all year long. Why, because my plants with higher humidity look better, grow better, flower better and set seeds better than those with lower humidity. That's good enough for me!

Fourth, infrequent repotting. I won't go so far as to say that Petrocosmeas resent repotting. I've never had a Petrocosmea show any apparent negative effects of repotting. I'm just saying that I don't think it is necessary. I get great results by leaving them along. As long as the mix is draining well and not washed away, my Pets seem very happy staying where they are. Also, I'm not aware of anyone or anything in nature that repots the Petrocosmeas in the mountains of China? Are you?

Last, maturity. By that I mean that I now feel that it takes three or four years of growth for a newly propagated Petrocosmea to reach it's full potential. My plants clearly perform better with each year of life they have...my older Pets perform the best every time! So, again, when considering a show plant....is it mature? This can be difficult to tell since the grower may have kept the plant smaller intentionally, and should therefore not be faulted for choosing to do so. However, bulk seems to improve performance....perhaps the larger root mass and foliar mass support more flower production?

So there you have the results of what I am seeing as I study these plants more closely over the past few years. I hope these observations will help those who are struggling with getting their Pets to bloom......and judges!!!.....consider bloom potential when awarding a Petrocosmea entered in bloom.

"The Experiment" - Growing Pets Outdoors

Having grown Petrocosmeas in just about every fashion possible INDOORS, I had to try growing them outdoors. Here's my story...........

I'm not sure if the problem was having too much time on my hands or having too many Petrocosmeas on hand, but the thought occured to me, and I just had to do it! Actually, I'm certain it wasn't the former, because there never seems to be enough time in the day.... Nonetheless, I'm now well on my way with an experiment in growing Petrocosmea outdoors in southwestern Pennsylvania. Pittsburgh is in USDA zone 6, and my outdoor growing space is pretty cool and shady. Our summer temperatures here are relatively mild, with lots of rain. As I thought about it, I realized that our climate here is pretty close to what I've read about the natural environment where many Petrocosmea species grow in China, so I figured...."why not?"

So, here's what I've done. First, I selected the plants I wanted to use a couple of weeks ago, and let them dry out to the point of being limp....I did this in order to avoid breaking leaves off of brittle, turgid plants. Then, I took an old terracotta "strawberry jar", (I've had this thing forever!!!) and filled it with a loose, but fertile soil mix that included lots of humus and a little composted manure. I selected a collection of species that offered variety. And, having groomed more than my fair share of dirty Pet leaves, I decided to fill the jar and start to pot from the top, in order to avoid soil from above falling onto the leaves of the plants below. This is backward from the way I would normally pot up a strawberry jar, but for the Pets, it worked flawlessly. And, since Petrocosmeas are "rock plants" I had to include a large rock on the top for some ornamentation and interest. The Pet species I used were : minor veined leaf form, rosettifolia forms #2, and #3, barbata, forrestii, begoniifolia, nervosa, and kerrii. I mulched any exposed soil with small gravel and watered them in with a vitamin root stimulant diluted in water. They will remain in total shade and I sited them so that they will get good air movement. Luckily the spot is also along the path I take into and out of the house each day as I go to work, so I can see my beloved Pets at the start and end of my dayI!

I'll let you know how the experiment progresses!

A Few More Baby Pictures.....

Well, you know how it is with proud parents and pictures of the "kids"...... I found a few more photos from the same P. 'Asa Blue' x begoniifolia cross. The photo above shows a large flower, very full petals, a pinkish coloration and some ruffling in the petals. The slight yellow marks in the throat are still there, and this one has some spotting in the throat. The peduncles on this seedling were also nice and compact, which helped to support the large flowers. This one was also kept for further evaluation. (Sorry that the photo is not in focus.)

This photo shows the flower from the first photo, beside of a sibling which has the more typical flower shape for the cross. I took this photo to show the difference in the roundness and fullness of the petals. The leaves also has a nice purple border, which came from the begoniifolia parent. P. begoniifolia is the only Pet that I've seen that has burgundy red underside to the leaves.

The first seedling to flower....... Wow, was it a surprise and was it different! It has ruffled petals, extra petals, yellow and green in the throat, and white splashed all through the petals. It kept these characteristics in the subsequent flowers to open....but was not as floriferous as I had hoped...I have kept it for further testing...hoping that with maturity, it will prove to be more floriferous.

And one that I kept calling 'Froggy' since it has an odd shape, and lots of green in the flowers..... This flower has four colors...green, white, yellow and purple! Of course, I kept this one to test further too......

Finally, as shot showing the foliage from a seedling...this plant, 'Keystone's Belmont' (photo of flowers in the previous post), was awarded 96 points in the New Gesneriads class at the recent show in Bufflalo. It won a second place ribbon in competitive judging, nudged out of first place by my other Pet. hybrid 'Keystone's Bluejay'. This hybrid shows a bit more of the P. flaccida grandparent in it's ancestry...which is one of the parents of P. 'Asa Blue'...it's mother.

I've been quite happy with the results of this cross. The variation has been stupendous and I am anxious to see the seedlings which I have selected as they flower in the second season this fall.

Baby Pictures - My Petrocosmea Seedlings

Now that spring is officially here in southwestern Pennsylvania, the sun is brighter, the hours of daylight are growing longer and the temperatures are warmer. The plants can certainly sense the changes. I am seeing strong, and rapid growth from the Petrocosmeas, as well as most of the other gesneriads. Today, I spent several hours in the basement growing area repotting seedlings, grooming last years older, yellowing leaves from the outer rows of the Pet rosettes, putting leaves down to root, and dividing those Pets that have formed offsets.

As I worked, I found myself working with the trays of seedlings from last year's most exciting cross...P. 'Asa Blue' x begoniifolia. I raised around 40 seedlings from that cross. As I worked wtih the seedlings in these trays, I was reminded of the flowers on each one as I picked them up one by one to scrutinize them and groom them. No offsets on any of them....Good!!! (I am choosing seedlings that show a reluctance to form offsets, since I feel that offset formation often ruins a beautiful showplant and spoils the flat, symmetrical contours of the rosettes.) The variation in the flowers from seedling to seedling was fantastic, and I was continually amazed at the different markings and shadings on the flowers. This cross gives me high hopes for the future of Petrocosmea hybridizing. I decided to share some photos that I took from some of the more exciting seedlings......

The photo above is a seedling from this cross. There were four seedlings that showed the extra petals in the center...which surprised me. Most flowers took the form of the petals from the begoniifolia parent, as well as showing the two yellow spots that the white begoniifolia flower exhibits. The seedling above is, so far, unnamed. I've kept it to test for another season of bloom and to test for offset production before deciding whether to name it.

There were a couple of realy odd flowers. This one shows lots of yellow in the throat as well as touches of yellow on the lower petals. I kept this one just to see what it does in the second season. The flower is not necessarily attractive, but it might be helpful in getting more yellow into the petals of future hybrids. This one also hints at striping in the petals....reminded me of chimera African Violet flowers.

I loved this one! The coloring is so delicate and the lower petals retained the greenish coloration seen here. I also liked the cupping of the petals...and the bell-shaped flower apperance. Again, I kept it, but have not named it so far.

The flowers above, were the first to show extra petals, and the deep blue coloring with the white center halo was consistent as the plant continued to bloom over a long season. Flowers were numerous and large. One additional nice thing about this seedling was that as it had finished it's round of bloom, it put up a second round of bloom about two months later...all of this on a seedling that was at that point, only eight months old. I named this one 'Keystone's Belmont' in honor of my college alma mater in Tennessee. The school's colors just happened to be blue and white also!

A trio of siblings from the cross....showing variation in coloring and shading. I kept all three of these. The one on the left was named 'Keystone's Barnswallow' in honor of the barnswallows that I remember so fondly from my childhood on my grandfather's farm.

Petrocosmea flaccida - Part II - Hybrids

In Part I I discussed the two clones of P. flaccida in my collection and the history and culture of this species. In this post, I'd like to begin to showcase some of the hybrids which have P. flaccida in the background. To date, P. flaccida may be the most widely used species in hybridizing. I can recall at least five named hybrids that have P. flaccida parentage or ancestry.



The oldest P. flaccida hybrid and the oldest Petrocosmea hybrid, for that matter, is P. 'Momo', made by Nagahide Nakayama of Japan, by crossing P. flaccida and P. nervosa. The plant, for me, grows very much like a large P. flaccida and is perhaps, a bit more floriferous, with slightly larger flowers than P. flaccida.




A couple of years ago, Mr. Nakayama did a remake of the same cross that produced P. 'Momo' and released two of the resulting seedlings. Those seedlings, named P. 'Asa Blue' and P. 'Imperial Butterflies' are improvements, in my opinion, over P. 'Momo'. I grow both of them and really like them. I have been successful in using P. 'Asa Blue' in one cross with P. begoniifolia.


P. 'Asa Blue' an improvement over P. 'Momo', was the result of a remake of the same cross that produced P. 'Momo'. The plant flowers several times a year, and the flowers are large and show. The plant also shapes very nicely.

The photo above, shows the flowers of the parents of P. 'Asa Blue' - P. flaccida, and P. nervosa. P. 'Asa Blue' is incredibly floriferous and flowers are larger than either parent with improved form. This hybrid is also fertile for further breeding. Seedlings inherited it's early, free-flowering nature.

Another hybrid, boasting P. flaccida as a parent is P. 'Short'nin' Bread'. This cross used P. forrestii as the seed parent. P. 'Short'nin' Bread' is a vigorous, attractive hybrid which can be grown quite large with good culture. It flowers freely at a young age, although generally only once a year, for me.

A sibling to P. 'Short'nin' Bread', P. 'Fluffer Nutter' has the same silvery felt covered leaves, but a more compact and neat leaf habit, seeming to take this from it's P. forrestii parent. This hybrid, sadly, is not free flowering, and is the only Petrocosmea in my collection which I have never flowered, even after several years of growing. Still the foliage is attractive.

A flower from one of the selected seedlings from my hybrid cross using P. 'Asa Blue' crossed with P. begoniifolia. These seedlings have been quite free flowering at a young age. Almost all have been attractive and selections have been difficult due to the large amount of variation I've gotten from the cross. (I wanted to keep them all!) I have so far, selected five or six to grow on for further evaluation. The seedling above is unnamed at this point. It inherited a nice deep blue color from P. 'Asa Blue' with flower shape and the white /yellow throat from P. begoniifolia.

P. flaccida is a wonderful old friend among Petrocosmea admirers. If you don't grow it, you should. It's flowers are among the darkest purple of all Petrocosmea species and it is a good bloomer. These characteristics are passed along to it's progeny in hybridizing, which gives it a secure spot among our growing list of Petrocosmea species and cultivars.

The First Show of Spring

The first gesneriad show of Spring! What better way to welcome Spring than to spend a weekend among plants and friends. And if those plants are gesneriads, even better. AND, if those gesneriads are PETROCOSMEAS then it's joyful indeed! I was priveleged to spend my first days and the first weekend of Spring among wonderful friends and wonderful gesneriads while attending the annual spring gesneriad show of the African Violet and Gesneriad Society of Western New York, held in Buffalo, NY. I have attended and judged this show for the past three or four years and it is always a superb time. This year was no exception.

While driving up to Buffalo from Pittsburgh, the promise of Spring was dampened somewhat when I approached Lake Erie near the borders of northwestern Pennsylvania and Southwestern New York. In the photo above, those white clouds in the background behind the vineyards are NOT CLOUDS...but the still-frozen Lake Erie!

Of course, once I arrived at the show, the frozen lake was a faint memory as the abundance of skillfully grown gesneriads took over my visual senses. I love, and grow many plants, many gesneriads too, but my heart always draws me to the Pets! The show this year has number of beautiful Petrocosmea among the entries. This year, I was able to both judge the show as well as enter some of my own gesneriads. I brought three of my new hybrids to enter in the class for "New Gesneriads". The only collection in the show, pictured above, was a spectacular collection of Petrocosmea hybrids and species grown by a master Pet grower...Paul Kroll. His collection won a first place award...not because it was the only collection, but because it also scored greater than 90 points. When exhibiting a collection, the pressure is on the exhibitor to showcase several well-grown plants that show the diversity among the plants within the genus. Pauls collection did a nice job of doing both. I felt that the choice of brown fabric complimented the green plants well.

The Petrocosmeas grown for the ornamental qualities of the foliage had a nice representation as shown here. The public was repeatedly drawn into the table with the Petrocosmea entries. For some reason, the foliar habit of Pets seems to mesmerize people.

A nice surprise this year was that an eductional exhibit entry also showcased some recent and ongoing work studying the Phylogenetic relationships of the species within the genus Petrocosmea! This exhibit was presented by a professor from Niagara University and showcased work being done there. I was quite familiar with the work as I have been honored to have been a small part of it through contributions of plant material, hybridizing data, and morphological information. The authors of the work are hoping to finish the study this year.

One of my entries, a selection of my hybrid cross between P. sericea and P. minor veined leaf form named P. 'Keystone's Bluejay' was honored with a first place award as well as selection for Second Best in Show! The comments and feedback from the judges were quite kind and welcomed. I was very excited to see such enthusiastic support and appreciation for my new hybrids. This is the only plant selected and named so far from that cross, which flowered last year. I have kept four other plants for further evaluation. Judges loved the silvery curls in the center of this plant. I was able to make several distributions of leaves from this plant, and hopefully, will see others exhibiting it in the near future.

The show had a number of spectacular gesneriads, designs and natural gardens. The artistic section of the show was especially nice this year. Petrocosmeas showed up in several of the natural gardens and terrariums this year too. It is great to see a growing interest in my favorite genus.