Rosa carolina and Some Hybrids

Much of my rose-collecting has been centered around Rosa carolina and its first-generation hybrids-- exactly why, I'm not sure, but there are some factors that might account for why I find this species so attractive...

• It has a relatively short stature;
• It suckers-- effectively propagating itself;
• The glandular flower buds with long stamens are neat;
• It's easy to breed with.

Being native to the Southeast disease is almost never a concern, and it can tolerate significantly more neglect and shade than the complex Chinensis-section hybrids. And the once-blooming habit has never bothered me too much-- after all, the extreme vast majority of other native plants flower once annually.

There is a smidgeon of phenotypic variation out there: the Guide to the Vascular Plants of Tennessee recognizes two subspecies, one, subserrulata, having eglandular flower parts, and ssp. carolina having the characteristic array of pedicel and hypanthia glands. Petal width, flower size and color, and leaf size, color, luster, and degree of corrugation vary too, of course.

R. carolina is widespread in Middle Tennessee cedar glades, in particularly rocky locations made to adopt a relatively small thicket form. These flowers are very pale pink, probably having been bleached white by intense sun.

A Jackson, MS plant with smallish flowers and narrow petals

A Jackson, MS clone with relatively narrow petals-- and are those stable "dimples" at the petal edge or just evidence of herbivory?

A Middle Tennessee plant of darker coloration

Relatively wide petals of an Oxford, MS clone

As with nearly every other rose species, the mutation creating the white alba variety has no doubt occurred countless times-- at some point white R. carolina was in commerce in North America, but currently no nursery offers it, although it is still apparently sold in Europe. And the mutation of some stamens into petals has given rise to the double form plena (which does not seem to be available either).

Fortunately this species has garnered the attention of some amateur breeders who were kind enough to share some suckers with me-- one of my favorites is '3/4 Native' from the writer of Mid-Atlantic Plant Research Center, Tom Silvers; the mother being a cross between the hybrid tea 'Fragrant Cloud' and R. carolina, and the pollen donor being R. virginiana (closely related to carolina, in the same section of the genus). Although the possibility for disease is certainly there, owing to the admittedly somewhat unhealthy hybrid tea heritage, it has proved to be quite resistant for me, even in very humid conditions.

Double but with a glimpse of stamens, '3/4 Native' is almost the ideal result from its parents-- the extra petals, saturated color, and foliage pigmentation from the Chinensis-based hybrid tea, with the wild habit and resilience of the Carolinae natives.

Another hybrid, of the parentage R. carolina X ('Red Dawn' X 'Suzanne') is a cull from Rose Hybridizers Association forum member J. Bergeson. It has interesting cupped semidouble flowers and an attractive arching form, but had some trouble with blackspot, and resembled R. carolina much less than other hybrids I've had.

Quite pretty-- but sadly I don't have it anymore, which might be for the best owing to Southeastern humidity.

The last I'll list here is a cross between R. gallica from Gaul, an important progenitor of many of the roses grown in Europe before the introduction of the repeat-blooming "Stud Chinas," and R. carolina-- uniting the carolinae and gallicinae sections in the most direct way possible. The plant is pretty as all wild roses are, but might be most interesting for what it represents genetically.

Carolina-gallica.

Although few carolina hybrids are commercially available, and many of those currently grown might not actually be the best use of space, if one is looking for roses of maximum ornamental value, the group represents what cultivars might be possible if native plants were used genetically in conjunction with the traditional Old World imports. This might not be the future of moneyed corporate rose breeding, but it certainly has seemed to become the theme among many amateur breeders-- which is certainly a good thing owing to the historical supremacy of hybrid teas and their relatives.

Boursault Rose 'Morletii'

The Boursaults constitute one of the most obscure classes of roses. Bred mostly in France in the Nineteenth Century, they are little more than novelties today, but likely succeeded as niche collector's items back in novelty-obsessed Victorian-era gardening, as their flowers arrive very early in the season, blooming just slightly later than the Banksias (a group of related climbing roses known to flower in conjunction with tulips and hyacinth). 'Morletii" is blooming now in central Mississippi.

'Morletii,' a Boursault from 1883

They are very distinctive in appearance, with violet-colored, totally-thornless wood, soft leaden leaves, and procumbent or climbing habit. They sucker very lightly, and are best grown as short climbers or large, arching shrubs. Traditionally, they are said to descend from Rosa pendulina, or the "Alpine Rose," but it is possible that a case of Nineteenth-Century misidentification occurred, and that they are really the descendants of the North-American Native R. blanda. 

Bred by Morlet (reportedly something of a charlatan) in 1883, the rose in question has semidouble flowers of a rather ragged shape much like crumpled paper, with a paler center marked by golden stamens. The flowers are short lived but the plant provides color for a few weeks in spring, before most other roses have developed flower buds. In my experience, it is quite sterile-- so there aren't any ornamental hips for fall; however, the leaves turn bright red come autumn. It is not much troubled by disease, but can get some black spot in humid climes.

Why grow Boursaults? Admittedly, the best thing this small class has going for it is its obscurity and history. Today they are much outclassed by other roses which are repeat-blooming and more disease-resistant. But I always find something charming and rustic about roses with "informal" (to put it charitably) flower shapes and a scrambly habit; one certainly can't image the likes of 'Knock Out' being as graceful next to a split-rail fence or in a mixed perennial assemblage. So I can safely grant the rose Luddite seal of approval to 'Morletii,' which is still currently sold by Rogue Valley Roses.

The Weedy Introduced Geraniums

I remember that, when I was little, I loved to look at springtime weeds-- especially the introduced annual Geraniums that are the subject of this post-- assigning my own common names to them and trying to find interesting variants. Among these Geraniums there's quite a diversity of leaf shapes, with the "Cutleaf" G. dissectum at one end, the staidly normal-geranium-looking G. pusillum in the middle, and G. molle rounding out the other end with its rotund leaves with little space between the lobes.

G. dissectum. Taller than its brethren, dissectum's flowers are some permutation of saturated carmine pink.

G. pusillum, in pale pink, approaching white.

Note that, as always, my IDs may be imperfect, and there are other introduced annual geranium species of wide distribution.

The flowers are what one would expect, small versions of the "civilized" varieties of cranesbill and the native perennial sorts. I suppose their size is an adaptation to the relatively ephemeral life cycle of these plants, facilitating speedy reproduction while requiring little energy expenditure. Their seed capsules have the classic cranesbill shape.

A blurb on Wikipedia-- without citation-- claims that G. carolinianum tolerates relatively alkaline soil conditions, which could very well be the case, given these plants' predilection to spring up among concrete rubble, gravel, and other limey substrates.

My affection for weeds crops up again-- they might be promiscuous aliens, but I think the introduced annual geraniums are charming.

Zonal Geranium 'Mrs. Quilter'

"Fancy-leaved" geraniums (Pelargoniums) were quite popular for bedding in Victorian gardens, so many of the fancy zonals grown today were bred/ discovered during the Nineteenth Century. One of the lesser-known cultivars is 'Mrs. Quilter.'

Striking leaves of 'Mrs. Quilter'

Nondescript pink flowers

The leaves feature prominent bronze-red zones on a chartreuse ground. The small flowers, like those of many other fancy pelargoniums, are not the focal point, and are a pretty but rather plain pink. The plant is not dwarf, and can become leggy, so for the bushiest plants rigorous pinching is required-- or the grower can regularly root new plants and discard the older shrubby ones.

According to the nursery Geraniaceae.com, 'Mrs. Quilter' was bred by Laing in the UK in 1860.

Kyuzo Murata's Rose Bonsai

Years ago I found a copy of Kyuzo Murata's (1902-1991) Four Seasons of Bonsai at a local library. I was delighted for several reasons:

• Murata used relatively unusual species for bonsai-- for instance, Virginia creeper, hydrangea, redbud, spiraea, and fothergilla. 
• He grew his plants in a very naturalistic style, with loose branching and a semi-wild look.
• The plants were often photographed in a garden setting where they grew normally, rather than in the polished confines of an exhibition hall.

Much of his work is a strong contrast against the multitude of tightly-wired, manicured juniper, pine, and maple bonsai. I've always had a predilection towards a more naturalistic style and Murata was perhaps the quintessential practitioner of this. 

His use of roses-- semi-woody plants not immediately suitable for traditional bonsai treatment-- is really magnificent. A photo of Murata's Rosa bracteata bonsai is widely circulated on the internet, seldom with attribution. The book also contained specimens of R. rugosa and R. wichurana, which are apparently not widespread across the net. These images are from a rather mediocre scan of the book:

Rosa bracteata. Growing roses in this manner requires years of diligent sucker removal-- the plant's natural tendency is to constantly replace the old woody growth with new basal shoots.

R. rugosa, for some reason called "Sweet briar," which usually refers to R. rubiginosa.

R. wichurana. Although there's a good grouping of woody trunks, the naturally spreading nature of wichurana is still evident. The plant is shown in fall, with its hips.

Two Solanaceae Weeds

For some reason I find the Solanaceae ("nightshade") weeds quite ornamental. Maybe it's just their strong resemblance to deliberately-cultivated plants, such as pepper, potato, and tomato, also in Solanaceae, that makes me look at them differently from other weeds.

Physalis peruviana, Peruvian Ground Cherry or Cape Gooseberry. First cultivated by the Inca for its edible fruit, it's now widespread globally both as a weed and an appreciated garden plant.

Solanum carolinense, Horse Nettle or Devil's Tomato. All parts are toxic due to the presence of solanine, which serves as a chemical pest defense.

Of course when we consider that the definition of "weed" is situational, and in home gardens quite subjective, maybe to me they aren't weeds! It'd be interesting to see if good cultivation and some pinching could make a passable ornamental plant out of horse nettle, for instance.

Leafy Sepals and Proliferation

The one 'Double Knock Out' seedling that I kept recently issued a new basal shoot, the blooms of which were quite leafy:

Large leafy sepals, each looking almost exactly like a normal terminal leaflet. The stamens have also proliferated into leafy structures.

These sepals are so leaf-like that they have both terminal and side leaflets. 

Underside, showing a very convincing petiole to the left.

Although at the moment I'm not sure what causes blooms to develop like this, I hope the trait proves to be stable. How novel it would be if this variety consistently made these little "boutonnieres," framing each flower with a cluster of basal "foliage" derived from the sepals.

Rose Hips, and Growing Roses from Seed

Rose hips have been ripe and full-colored for some time now. In the case of the species, hips represent roses' primary ecological contribution (food for wildlife), and in many other roses hips are an important part of the late-season display.

Ripe hip on R. carolina, on the Natchez Trace

Although they are seedy and not very fleshy, hips are edible; in World War II in Britain, the hips were gathered for use as a vitamin C supplement. There are also many recipes for rose hip jam. Some amateur breeders have expressed interesting in selecting for hips for human consumption, but as far as I know little has come of this effort-- so for edible fruits from Rosaceae we'll have to stick to such staples as cherry, apple, pear, strawberry, peach, plum, et. al.

Hip on R. spinosissima repens at the National Arboretum

As many roses hail from regions of the Northern Hemisphere with appreciable winter cold, the most common method for breaking the seed dormancy is stratification. Seeds can be left in the fridge for months, up to a year or two. Many will not germinate even when given this winter period, so pots of rose seeds should be kept for several years after sowing. The wearing off of natural germination inhibitors is also a factor.

Unripe hip on large flowered climber 'Stormy Weather,' at the National Cathedral Bishop's Garden

Conventional wisdom dictates that seed be collected when the hips are ripe, but in practice it is possible to have equally good germination rates if the seed is collected slightly early. Once I was able to raise seedlings of Rosa rubiginosa from hips that were completely green-- so if you are in a pinch, late-season hips that aren't visibly ripe can still yield seedlings.

Here is the method that has worked best for me:

1. Clean the seeds and wrap in a damp paper towels, wet with dilute Captan (fungicidal) solution; store in labeled ziploc bags
2. Refrigerate for six months before checking the bags for any germinations; remove and pot seedlings as they appear
3. Water the potted seedlings with dilute Captan

A major problem I've encountered is damping-off, with affects the base of the seedlings and causes them to rot. The fungicide Captan has proved to be an effective preventative. I have also read of a layer of perlite over the soil being used, as this reduces the moisture level around the seedling base where the fungus wreaks havoc. In my experience most commercial fine-texture seedling mixes work fine as long as they drain freely enough.

Seedlings from repeating parents can bloom very quickly after germinating.

Species or once-bloomer seedlings take years to grow before they bloom, but seedlings from reliably repeat-blooming parents bloom in the first year.

For the species, propagation via seed is preferred since each seedling will be genetically distinct. Seedlings of roses with complex pedigrees will usually be inferior to their parents and may exhibit significant visual differences-- the facet of mystery is what makes raising them so fun, even though the seedlings will likely only be of value to you.