Flora Wonder Blog: The Rosaceae Family

Holodiscus discolor

Karl Koch

Every day I pass a weed-bush on the public road near the nursery. Holodiscus discolor grows amongst the blackberries, poison oak and Oregon grape, and it is a complete non-event for ten months out of the year. The "Ocean Spray" is gorgeous for two weeks when it is freshly blooming, then absolutely horrible for the following six weeks when the flower sprays wither and turn to brown. 100 degree F weather is not its friend, and the ugly flowers persist like uninvited relatives who stay too long. It came to my attention that Holodiscus is in the Rosaceae family, which doesn't seem right, but its membership was confirmed by the Hillier Manual of Trees and Shrubs (2014). I checked the old Hillier 2^nd edition – which, by the way: Sir Harold, is falling apart – and yep, even back then the David Douglas introduction (1827) was included in Rosaceae. The botanic name Holo is Greek for "whole, entire disc," referring to a section of the flower below the pistil. Discolor means "two-flowered" since the leaves are green above and hairy gray beneath. But the Holodiscus discolor name doesn't roll off the tongue very well, and we can blame the German botanist Karl Koch (1809-1879) for that. He was best known for his botanical explorations in the Caucasus region, and he never ventured to America to see our crappy Northwest bush; and actually I hate that part of botany: that some European geek is "credited" with a plant's scientific name when the locals who grew up with, and made use of the plant were never consulted.

Since I had my Hillier's open, I proceeded to page through to see what other genera is placed in the Rosaceae family. Of course I know that roses – Rosa – is in the family, but I discovered quite a number of plants that I have never heard of before, such as Polylepis, Rhodotypos, Sibbaldiopsis, Sibiraea and Heteromeles. You don't know any of them either, am I right? The latter, Heteromeles, is a monotypic genus that used to be included in Photinia. H. salicifolia is the "Christmas berry," a shrub with white flowers that later produces bright red berries that are used for Christmas decorations in its native southern California. This "holly" is what gave rise to the name of the famous film capital – Hollywood. I have been to southern California quite a number of times, but I have never knowingly seen a Heteromeles.

Photinia villosa

Speaking of Photinia, it is also in the Rosaceae family, another fact that I didn't know until I began this blog. What is most typically seen in horticulture is the cross x fraseri which is P. glabra – a Japanese/Chinese native – crossed with P. serratifolia from China and Taiwan. The hybrid's new growth can be spectacular, but it often occurs in late April when we can still receive hard frosts. Well-groomed hedges can be brilliant with red tops one day and then turn to black mush the next, but usually after a month they bounce back with new growth again. I used to grow P. villosa, another Asian species, but I cut it down as it grew into an unwieldy large tree that simply didn't fit into the landscape. The origin of the word Photinia is from Greek photeinos for "shining" or "bright," though judging by a large collection of species in Portland's Hoyt Arboretum, most of them have grown into large shrubs and trees, so the shining brightness is not so apparent, not even in spring. Actually the Hoyt trees are downright ugly.

Stephanandra incisa 'Crispa'

Stephanandra tanakae

I also did not know that the Stephanandra genus is in the Rose family. Hillier describes them: "Though of subtle beauty in flower, their graceful habit and attractive foliage qualifies them for a place in the garden." I guess I would agree with that – I have one in my front yard where it sits minding its own business, never really impressing me or anyone else. Both the incisa species and the tanakae species root easily, but sales were always very slow. The generic name comes from Greek stephanos meaning a "crown" and aner meaning "man" since the stamen supposedly looks like a crown. I would never have thought to name it that and I think it's another example of a poorly named plant. Philipp von Siebold is guilty in this case. The specific name tanakae honors Yoshiro Tanaka (1836-1916), a noted Japanese botanist.

Spiraea morrisonicola

Hillier relates that Stephanandra is "a species of shrubs allied to Spiraea and native to E Asia." Well, I didn't know about Steph's affinity to Spiraea – a genus, the latter, that I featured in last week's blog about Spiraea morrisonicola. Spend enough time in horticulture/botany and you will feel cozy about many relationships amongst plants. It seems that everybody (sort of) sleeps with everybody. Though there's no need to do so, I wonder if you could successfully graft a Spiraea onto a Stephanandra, or vice versa?

Spiraea japonica 'Magic Carpet'

Last week I mentioned that plant snobs generally poo poo Spiraea, but that they shouldn't. As an example, ten years ago I employed interns from Poland, the Czech Republic, Germany and Japan. I conducted a survey – after they served about 6 months at the nursery – about what was their favorite plant. The Polish intern, who far excelled beyond light-bulb-changing jokes, declared that Spiraea x 'Magic Carpet' was his favorite. That statement elicited a guffaw of derision from a spoiled American kid who was a college horticulture graduate (wooo), and who's father operated a successful conifer/Japanese maple nursery. The brat couldn't believe that anyone would admire a Spiraea, that the intern was a simpleton beyond belief. 'Magic Carpet' would not have been my choice either, but after the Polak's declaration I began to admire the Spiraea with renewed interest and I totally understood and valued his opinion. If the Man from Mars – or an intern from Poland – admires the Spiraea cultivar over the thousands of plants at Buchholz Nursery...then you should just shut up and appreciate his perspective.

Kerria japonica 'Variegated Prostrata'

Kerria japonica – are you kidding me? – is that also in the Rosaceae family? I guess so – again, according to Hillier. Kerria japonica is a monotypic genus with small green leaves and small yellow flowers. I've never tried to propagate and sell it, but I do have a plant behind my house that I acquired (from Siskiyou Nursery) as Kerria japonica 'Variegated Prostrata'. Despite the incredibly invalid cultivar name it is a pretty little bush – but not quite so prostrate as it (after 20 years old) is now more tall than wide. Oh...and also, the variegation is mostly gone as the green shoots far outnumber those splashed with cream white. According to Hillier this cultivar would more accurately be known as 'Picta' but nevertheless, since it basically stays green, you only have the species, not a cultivar. The deciduous shrub is native to China, Japan and Korea, and was introduced by William Kerr who introduced the cultivar 'Pleniflora'. Kerr (died 1814) was a mere plant hunter, but he was championed by Sir Joseph Banks and was sent to China, and he is considered the first western professional full-time plant hunter in that country. The first in China – that is amazing when you think about it. Unfortunately he was transferred to Ceylon (Sri Lanka) where he died two years later...in consequence of some "evil habits he had contracted," namely opium addiction.

Cherry tree at the Portland Japanese Garden

Otto Luyken

It is not surprising that the Prunus genus also resides in the Rosaceae family. Generally I have steered away from the genus, from a grower's point of view, although I do admire the flowering Japanese cherries every spring. Prunus is a huge genus of trees and shrubs which includes plums, cherries, peaches, almonds...and of course ornamentals such as P. laurocerasus, the "Common Laurel." I had a hedge of it next to the house when I first moved onto the nursery, and I diligently pruned it my first spring. The following spring when it needed pruned again I ripped it out instead – I wasn't going to waste another minute of my life on a damn hedge. Besides, the smell of its leaves made me sick. Equally repulsive is the 'Otto Luyken' laurel, the plebian greenery that is used in parking-lot plantings. Somebody smashed one with their car a few years ago at a Safeway store; the cripple remains and no one has ever attended to it. It is amazing that 'Otto Lukens' are now ubiquitous in America – I guess we have a lot of parking lots. Otto L. (1884-1953) was director of the Hesse Nursery in Weener, Germany. Geeze, how would you like to be from Weener? ...but I guess we are all from one. His dwarf laurel was discovered in the 1940's, but sadly it was not introduced until 1953, the year of his death.

Malus fusca

Malus – the apples – are of course members of Rosaceae. While most think of them for their fruits, I'll go on record as an aficionado of their trunks, their torsos. One of my all-time favorite of tree trunks is M. fusca – the "Oregon crabapple" – which is growing at the Washington Park Arboretum in Seattle. I have never seen its fruits, whether yellow, orange or red, and its top is unspectacular, in part because it grows in considerable shade. Writing about it makes me realize that I haven't seen it in a half dozen years, so I think I'll undertake a road trip to Seattle this fall.

I have seen a lot of Malus species in various gardens, so I'm happy that someone else grows them since I never have. Some of the flowering crabapples are spectacular in bloom, and they can be very attractive in autumn with their bright fruits, but a neighbor on Vandehey Road near the nursery planted an alley of about 30 trees, all the same cultivar. They bloomed beautifully this past spring but now they are infected with some kind of crud. The leaves are all shriveled up now, in mid July, and hopefully they'll defoliate soon. Malus? Malice indeed.

Crataegus monogyna 'Inermis Compacta' at RBG Edinburgh

While the trunk of the Malus fusca specimen is wonderful, the best torso that I have ever seen – well, except for my wife – is a Crataegus monogyna inermis 'Compacta' growing in the outstanding rock garden at RBG Edinburgh in Scotland. Could they ever have imagined that 'Compacta' would grow so large? My last visit was ten years ago; but please, it must still be there...and don't tell me if it's not. I have grown the "dwarf" hawthorne most of my career, and fortunately have never endured any disease or insect issues. My trees are beautiful with white flowers in spring and brilliant red fruits which persist from fall through early winter, and there's enough of them to keep both me and the birds happy. The cultivar is outstanding in winter as well because of its stout structure. I used to be also, but now...

Crataegus calpodendron

Crataegus calpodendron is another hawthorne species, and don't you think its trunk is amazingly similar to that of the earlier Malus fusca? Of course; these two creatures are cousins in the Rosaceae family. Was the calpodendron photo taken at the Arnold Arboretum in Boston? I think so, as the species is from eastern North America, and it is known as a "round-headed tree; very floriferous; bears orange-red, pear-shaped fruits," according to Hillier. I cannot discover the meaning of the specific name calpodendron, though of course dendron is Greek for tree. A cookie goes to whoever can inform me. Crataegus is from Greek kratos for "strength" and akis for "sharp," referring to the thorns on some species. I don't know about Native Americans with C. calpodendron, but with C. monogyna in Europe the Scots have a saying: "Ne'er cast a cloot til Mey's oot." It is a warning to not shed any cloots (clothes) before summer has fully arrived and the hawthornes are in bloom. I have known and employed a number of Scotsmen in my career, and my advice is that they should never take their clothes off, and we'll leave that to their sisters.

Sorbus alnifolia

Sorbus sargentiana

Well, if Crataegus and Malus are both members of Rosaceae, of course Sorbus must also be. The name sorbus is from Latin sorbum for "serviceberry" and sorbus for "servicetree." A Sorb was a member of a Slavonic people from east Germany, and may be another explanation for the origin of the word. The rowans are not my favorite tree, I quickly confess, though I have nothing against them in particular; and in fact in last week's blog I declared my admiration for Japan's Sorbus commixta. It's perhaps that the Sorbus are a bit too formal for me, with something of a "manufactured" look...with their perfect canopies and glossy fruits. I guess I desire a tree with less predictability, with more flaws maybe but with the potential for more fun and spontaneity, such as I find with my wife. Many times she drives me crazy, but at least I am never bored with her.

Amelanchier laevis

Amelanchier alnifolia

Another "service" tree in the Rosaceae family is the genus Amelanchier, a tribe mainly native to North America. I have never had one on my property but Hillier describes the genus as "beautiful and very hardy small trees or shrubs." I mention them here because thousands are produced each year by Oregon's large shade-tree nurseries, though I doubt that I would ever be able to sell even one. A. alnifolia displays an alder-like leaf obviously, and it is a western North American native that was introduced by David Douglas in 1826. Amelanchier laevis is also a North American species and it is known for fragrant white flowers in May followed by orange-red foliage in fall. Surprisingly you don't readily find the "serviceberry" available in Oregon's retail garden centers, but if I ever do stumble upon one I might just buy it. I guess that my previous problem with Amelanchier is that I toured a medium-sized shade-tree nursery in Oregon when I began my career. They grew thousands of Amelanchier and a lightly-branched 7-8' tree could be had for only 12 dollars. Maybe they each cost 11 dollars to produce, but when you grow thousands of them the math works out. I don't know much about the genus really, but I do know that the nursery I just mentioned folded during our recent brutal recession. A time and place for most everything, but never a guarantee for anything.

Rubus spectabilis 'Golden Ruby'

Pyrus pyrifolia

Pyracantha angustifolia

Potentilla dickensii 'Nana'

Aronia 'Autumn Magic'

Chaenomeles cathayensis

Other Rosaceae genera include Rubus, Pyrus, Pyracantha, Potentilla, Pseudocydonia, Aronia, Chaenomeles and more...but I don't want you to grow weary of the family; like I said: as with uninvited relatives who stay too long. Just a final nod to Portland's famous International Rose Test Garden to celebrate perhaps the most important member of the Rosaceae family, Rosa. A few cultivars are presented below, and beware if you visit this garden on a warm summer evening as the heady fragrance can turn a cold prude into a hot lover.