Plant Rambles

-by Andrew Osyany

Plant Rambles by Andrew Osyany is an article in the Ontario Rock Garden Society Journal - November 2003

Andrew Osyany gardens 60 miles northeast of Toronto where he now has seedling beds resulting in far higher surval rates - which, together with the root prunings, means plants coming out of our ears!

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Common and wonderful
The distribution maps show Houstonia caerulea covering the entire Eastern U.S., with the exception of Florida. The Flora of Nova Scotia mentions it being often abundant around Halifax and in the north-central area. The Flora of Canada extends its range westward questionably into Ontario. My sightings have only been in different places in New England and along the Appalachian mountains down to North Carolina. Clearly it is a widespread plant, but not necessarily easy in our environment. Probably where it is easy to grow, it is treated with contempt.
Houstonia caerulea	Closely packed basal tufts of small (7mm) ovate (mostly) glabrous leaves rise only about 2cm. The tufts can be small, but can glom into a fairly large mat. Flower stems are about 10-20cm long and initially are unbranched but, as the season progresses, one or two little side branches elongate and replace the spent flowers on the principal stem. The first flush in May is the heaviest but there is, or can be, sporadic bloom for a couple of months. Flowers are typical four-petalled Rubiaceae type pointed petals, each about 4mm long, light blue or violet at the tips, fading to white with a yellow centre. Lovely individually, enchanting in large groups. Unobtrusive seed capsules house a few small dark seeds. Needless to say, with such a large area of distribution, there are lots of local variations, some populations are utter gems, others are rather worthless in comparison.
Of course, I wanted to have Houstonia caerulea in my garden (no, it is not a typo, it was my garden, as this goes back to my distant bachelor days), but purchased plants did not thrive and seed-grown plants have not persisted. Yes, I asked and read about the required conditions - after all, just seeing them grow in diverse places shouldn't make me presumptuous enough to think that I know what the plants want. Instinctively, I always want to blame pH problems for apparently intractable situations, and it is true that I have generally seen the plant in what appeared to be slightly acidic conditions, and my situation has always been dead neutral. But the advice did not make for success. For such a common plant, it is unexpected that seed is not always available in seedexes. I tried to collect some from my current little tuft, but I have ended up with very little and will have to make a difficult judgment call as to whether to hang on to the crop, or recklessly give it away, in the belief that Houstonia caerulea is here to stay. The current little tuft comes from AGCBC seed two years ago, and the first flowers were in July 2002 while the plant was still in a seed pot. I decided to tuck it into one of our troughs and it came through last year's unusually hard winter just fine and has finally finished blooming in mid-September. Were it not for my wanting to collect seed, I could have been barbering the tuft, but even with the capsules at the end of the stems, it's not making the trough look unkempt.
The illustration, taken from Britton & Brown, is a good botanical drawing, but does not convey the beauty and attractiveness of the plant. Colour printing is hugely expensive. so we will likely be continuing with line drawings. However, with our web site, we can have colour pictures available to our largely internet-connected members. I know that our web-master welcomes pictures and really it is up to our authors to provide them to him so that we can have the slide illustrations for our articles. Gee, in this case, the finger seems to be pointing at me...
Houstonia canadensis	There are at least 18 species in the genus. I have also grown H. nigricans and H. pygmaea and I recommend them both. On Manitoulin Island we came across H. canadensis, which was mostly white but otherwise very much like H. caerulea. Incidentally, the Flora of Canada says that in H. caerulea the peduncles are one-flowered, while in H. canadensis the peduncles are several-flowered. H. longifolia is reputed to be in Ontario. From the illustration it looks quite attractive. I also want to draw to your attention H. minima and rubra, which come from further west. Mostly, houstonias are perennial rather than annual. Some, at least from illustrations, don't look terribly worthwhile. If you prefer pink or red to blue go for H. pygmaea, rubra, nigrescens. Some members of the genus you will find under Hedyotis rather than Houstonia. I do not know the taxonomic reason for this and I have not bothered to find out. In addition to the usual seedexes try the various Western seedsmen. We rock gardeners are not very well served for seeds collected in Eastern North America so I cannot refer you to commercial seed sources in the east. If only somebody could make me eat my words, I would be happy. For instance, there are lots of interesting things on Manitoulin Island that should be collected in addition to the Hymenoxis herbeum that Harvey Wrightman has as plants and Gardens North as seed.
More in the family
The Rubiaceae are thought of primarily as tropical and semi-tropical (coffee, gardenia), but there are some important temperate members as well.
Mitchella repens This sub-shrub is an easy and long-lived woodlander; my bunch is now 19 years old and has spread only modestly. Some years ago we planted Dicentra 'Bacchanale' as a companion, which ramped all over and through the mitchella but did not manage to overwhelm it. Smallish dark green half-shiny ovate leaves make for an attractive mat. Typical white Rubiaceae flowers in the spring, about 1cm across; followed by small red berries in the fall. Propagation is easy by layering and cuttings, though we have some plants a bit of a distance from the mother plant, so it must seed a little as well. Deno says that the seeds do not tolerate dry storage. Bedstraws-fellows Galium is perhaps the largest genus in the family and it houses some dreadful weeds with gangly and bristly stems, minuscule but very fecund flowers. Galium odoratum, commonly known as sweet woodruff, is moderately attractive and will survive dry shade. Survive, heck, it will thrive in dry shade! It's a member of the Vinca minor-Aegopodium podagraria Horde of the Ramp. But in Turkey you can find some exquisite minuscule sub-shrubs like Galium cilicicum which can proudly take a place in any small trough, with its congested little branches, small leaves and quite nice-sized white flowers. This is not difficult to grow. The genus Asperula probably has more to offer the rock gardener. AA. gussonii, nitida, suberosa, are desirable little gems, well worth growing. There is a light pinkish tinge in some asperulas. In this case, apart from the seedexes, you are probably best off checking with the Czech seedsmen.
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