Friday, February 16, 2018

Conifer Blue

Chamaecyparis obtusa 'Splitrock'

Pinus mugo 'Mr. Wood'

Abies veitchii 'Glauca'

Ginkgo biloba 'Blue Cloud'

John Lindley
Imagine the botanists of yore sitting in their studies at their universities or botanical gardens: they would be happy to know the study of botany continues in the 21st century, in fact it is more wonderfully revealing than ever. But what about horticulture? They must have known that before them the ancient cultures had intervened with nature to produce better olives, apples and grains. Could they have imagined that one day normally green species would have horticulturists discover and promote blue variants? Do you think that Siebold and Zuccarini, two German botanists who first described Chamaecyparis obtusa, could predict that we would be planting a blue hinoki like 'Splitrock'? I'll bet that Antonio Turra (1730-1796), the Italian botanist who first described Pinus mugo, would never have guessed that conifer aficionados would one day covet the miniature blue 'Mr. Wood'. When John Gould Veitch introduced the green Abies veitchii from Japan, it was first described by the English botanist John Lindley. Now I have the silver-blue 'Glauca' in my collection. And when Linnaeus first described Ginkgo biloba in his publications he certainly could not have foreseen the Buchholz Nursery introduction of 'Blue Cloud', allegedly.

Everyone admires blue, maybe because we react happily to blue skies. In polls in both Europe and America blue is considered peoples' favorite color. Even though the Japanese flag is red and white, my wife Haruko also supposes that blue is the favorite color in Japan. I don't know about ancient Greece, though, for they classified colors by whether they were light or dark and not by their hue. Kyaneos for “dark blue” could also be used for dark green, black or brown. “Light blue” or glaukos, could also mean light green, gray or yellow.

Acer japonicum 'Ao jutan'
Pinus parviflora 'Aoi'

Haruko tried to explain for me again (10th time) how the Japanese word ao can be used for both green and blue, and that aoi is an adjective – or was it the noun? All I know is that the maple Acer japonicum 'Ao jutan' has green leaves and that Pinus parviflora 'Aoi' is a blue-needled pine. I get agitated by her vague language, or so it seems to me, but it's not worth a marital fight, and I have to accept that her explanation is beyond me. Anyway, blue is a fun color, so let's have a look at some blue conifers.

Picea pungens 'The Blues'

I have grown Picea pungens 'The Blues' for quite a few years and I think it has one of the best cultivar names in horticulture. It originated at Stanley & Sons Nursery, Oregon as a more-weeping and silver-blue mutation on the old Picea pungens 'Glauca Pendula'. Larry Stanley was/is a keen plantsman and when he noticed the mutation he thought he might have something wonderful; in a large or more plebian nursery the potential might have been overlooked. The photo above is at Stanley's Nursery and I take it to be the original, or one of the original grafts from the mutation. It is grown by the thousands now, but sadly Stanley doesn't get a dime whenever one is sold. 'The Blues' has a stout leader and you could probably grow it to a considerable height, but I warn you that if you turn your back on it for even a short time the leader will begin to wander sideways and you cannot resurrect it.

Cedrus deodara 'Feelin' Blue'

Another weeper with a great name is Cedrus deodara 'Feelin' Blue', but its color is more gray-blue than the shiner 'The Blues'. Monrovia Nursery describes it as “the lowest of the dwarf cedars...” but it is not* and they should get out more. It can certainly be grown low but we prefer to stake ours into small upright weeping trees, and in 10 years we can achieve about 8' in height when grafted onto C. deodara rootstock. The growth rate is slower if propagated on its own roots. I got my start of 'Feelin' Blue' from Kools Nursery in Holland, and no wonder because it was discovered (seedling origin) in Boskoop, Holland in the 1980's. The C. deodara species is native to the western Himalaya and I have seen old specimens in northern India at about 10,000'. The botanical name is derived from the Sanskrit devadaru which combines deva for “god” and daru for “wood” or “tree.” C. deodara is the national tree of Pakistan, but the most cold-hardy** selections come from the Paktia Province in Afghanistan.

Cedrus deodara 'Vaneta'

*C. deodara 'Vaneta' is much more dwarf and low. So is C. libani 'Whitehouse WB'.

**I have grown some of these: 'Karl Fuchs', 'Polar Winter', 'Eiswinter' and others that are hardy from -15 F to -22 F, but I would considered 'Feelin' Blue' to be no more hardy than -10 degrees F.

Juniperus horizontalis 'Icee Blue'

There are at least two conifer cultivars named 'Icee Blue': one is a Podocarpus elongatus and the other a Juniperus horizontalis. I don't know which was named first, but it was bad form to have likewise named the second one. The J. horizontalis species is native to northeastern North America where it can be found growing in rocky soil and over cliffs. 'Icee Blue' forms a low-growing dense mat that stays less than a few inches tall, but it can be problematic in Oregon winters where the constant rain can cause shoot die-back. Maybe the problem is my own, for I have happy soil with plenty of irrigation, and perhaps my long new growth is too soft to withstand the winter.

Podocarpus elongatus 'Icee Blue'
Podocarpus elongatus is commonly known as the “Breede River yellowwood” from South Africa which grows into a multibranched bush, and it is the national tree of that country. The specific name is due to relatively elongated leaves in comparison to many other Podocarpus.* The type features blue-gray leaves but 'Icee Blue' is much deeper in color. It should be grown in full sun for best color, but unfortunately is only hardy to USDA zone 9 (20 degrees F).

Podocarpus henkelii

*P. henkelii has much longer leaves, but it wasn't discovered until P. elongatus was already named. Oops.

Cupressus arizonica var. glabra 'Blue Ice'

I don't know – or really want to know – the difference between Cupressus arizonica and C. arizonica var. glabra, but in the Hillier Manual of Trees and Shrubs (2014) it states that the var. glabra is more common in cultivation. A cultivar with stunning blue foliage is 'Blue Ice' which grows into a small conical tree. According to Hillier it originated in New Zealand about 1984. Shortly thereafter the now bankrupt firm of Duncan & Davies sent samples of 'Blue Ice' and Chamaecyparis obtusa 'Fernspray Gold' to the large wholesale nursery where I toiled. My employer showed the samples to me, but stated, “What am I going to do with these?” His nursery was frankly a boring place with mugo pines, Alberta spruce and Rhododendrons by the many thousands. I found the two conifers to be fascinating and I offered to buy them. I was starting my own nursery then so he gave them to me gratis, and after a few years I had both in production, probably the first company in North America to offer them. 'Blue Ice' is fast growing and I took a 6' specimen to our Farwest Nursery Show where it was an instant hit. At one point we propagated about 5,000 grafts and sold them as lining-out-stock...which is funny because we don't produce even one now. The problem is that the plants weren't hardy enough for most of my liner customers' customers. When they were dug from the field the stress caused them to produce unsightly gray male pollen, and if they were grown in containers they would flop around and require a stake. On their own roots – which I was never very successful at – they grow thin and feeble. Worst of all the grafted tops would grow too fast in the field and the roots (on Cupressus arizonica) couldn't keep up, so after a rainy windstorm the field of 'Blue Ice' would all be leaning at a 45 degree angle. We had about a 12-year run with it, but now nobody even asks.

Chamaecyparis pisifera 'Baby Blue Ice'

You get it by now that the word “ice” or “icee” sounds catchy with the word “blue,” and another conifer is Chamaecyparis pisifera 'Baby Blue Ice'*, which I admit is a fun name to say. It forms a compact pyramid grown either in a container or in the ground, and my oldest specimen (above) is now 6 or 7' tall. The pisifera species (Latin for “pea bearing” due to the size and shape of the seed cone) strikes readily from cuttings at just about any time of the year. The various cultivars are hardy to -30 degrees F and are relatively problem free; my only trouble is a wet snow that makes me want to dump my outside plants, but by the following summer they look good and compact again. 'Baby Blue Ice' was discovered by Stanley & Sons Nursery, the same company that found Picea pungens 'The Blues', in 1998 as a dwarf mutation on C.p. 'Baby Blue', the latter a cultivar nobody grows any more.

Picea pungens 'Baby Blue Eyes'

*Baby Blue Ice is a cute name. There also exists a 'Baby Blue Eyes' for a Picea pungens cultivar, and I grow one in the Flora Wonder Arboretum.

Picea engelmannii 'Blue Magoo'

When I began my nursery years ago I grew a lot of conifers from seed. The resulting seedlings might yield something interesting, but if they didn't you could either throw them away or perhaps use them as rootstock (which I still do with Japanese maples). In the mid 1980's I germinated a few hundred Picea engelmannii, and three years later I set aside about five of them that were the most blue. These were grown in the field, and one became my favorite, so I propagated and named it 'Blue Magoo'. The branches did not weep at all, but the new shoots drooped in spring giving the tree a graceful appearance. I sold a fair number because others agreed, and the western North American species is hardy and relatively easy to grow. Well – easy – except the species is prone (along with Picea pungens) to attack by a dreaded moth which lays eggs in the terminal leaders, and as the larvae develop they kill the spruce tops. Dwarf and miniature cultivars of P. engelmannii are not targets for the moth for they prefer to infest the succulent leader at the top of taller trees. Rather than a battle with the creatures with chemical control, I just don't grow them anymore. Buchholz Nursery is too small and diverse with affected trees in many locations, so preventative measures are inconvenient and costly. You win some, you lose some.

Picea pungens 'Blue Pearl'

Picea pungens 'Pali'

Picea pungens 'Herman Naue'

Picea pungens 'Procumbens'

I asked Seth what was his favorite blue conifer and he responded Picea pungens 'Margarite'. Yep, that's a good one, but I don't have a photo to prove it. But there has been a long debate about what is the “best” Colorado blue spruce...which can't be determined until we all agree on what best means. As I mentioned with Picea engelmannii cultivars, I now steer clear of the large-growing pyramidal cultivars such as 'Hoopsii' which was very popular at the beginning of my career. 'Thompsen' (from Denmark) was just as silver-blue but it too was prone to moth attack. Even the more-dwarf and compact 'Sester's Dwarf' suffered some damage, and there's nothing worse than a formal pyramidal tree without its top. On account of that we grow the miniatures like 'Blue Pearl' and 'Pali' Others that are slow-growing – but not “miniature” – include 'Early Cones', 'Ruby Teardrops' and 'Herman Naue'. These cuties produce erect purple cones in the spring, and as summer progresses the cones turn blonde-brown and dangle downward. None of these coners are very profitable for the nurseryman, but then they are easy to sell. Two clones that creep low and at a faster rate include 'Procumbens' and 'Dietz Prostrate', and they are very effective when planted in front of upright golden conifers like Pinus sylvestris 'Gold Medal'.

Juniperus deppeana 'Ohmy Blue'

Juniperus deppeana is the “Alligator bark juniper,” a species from dry areas in central and northern Mexico...up to Arizona, Texas and New Mexico. Other than the interesting checkerbark I find the species to be mostly ugly. Botanists still haggle if there are five distinct varieties: var. deppeana, var. robusta, var. sperryi, var. zacatecensis – the four of which don't interest me. The fifth variety is pachyphlaea and it is known for stunning blue foliage with white resin spots. Thirty years ago I was visiting the garden of the late Dr. Bump of Forest Grove, Oregon, and he led me to a seedling tree of J. d. var. p. I uttered “My God, that's blue.” He invited me to take cuttings if I wanted, and I did. To keep track of it I had to give it a name, and I couldn't call it 'My God That's Blue' so I chose 'Ohmy Blue'. It wouldn't root for me, but I did graft a few onto Juniperus scopulorum 'Skyrocket'. Over the years the grafts onto 'Skyrocket' were not usually successful, besides sales were weak because I was apparently charging too much for a mere juniper. I haven't propagated it in ten years but I do keep a nice specimen in the collection. The specific name deppeana honors Ferdinand Deppe (? - 1861), a German botanist who had given the species a name previously used for another species; which is not allowed so it was changed to deppeana. The variety name pachyphlaea is from Greek pachy for “thick, dense, large, massive,” and I don't know phlaea unless it refers to the bark.

Pinus cembra 'Blue Mound'

Pinus cembra 'Blue Mound' is a dwarf dense tree, and the finder of it – I forget who he was – told me that the original seedling did indeed grow into a “mound” shape. He conceded though, that despite its name all grafted propagules will eventually assume a pyramidal shape. This most garden-worthy “Swiss stone pine” can eventually reach 10' in height – mine is already 8' tall at 30 years old. Horticulture is replete with name tags – like the Podocarpus elongata that I mentioned earlier – that can seem quite inappropriate down the road.

Ephedra equisitina 'Blue Stem'

Even people who are familiar with horticulture are surprised to hear that the Ginkgo genus is (somewhat) classified as a conifer, or at least in the Hillier Manual it is listed with the conifers. Even more strange, I think, is when I first discovered the Ephedra genus included with conifers in Krussmann's Manual of Cultivated Conifers, a comprehensive reference book that I began using at the beginning of my career. Hillier doesn't go so far, and Ephedra in the Ephedraceae family is included in the Trees and Shrubs section. Hillier concedes, however, that Ephedra is, "A genus of great botanical interest, providing a link between flowering plants and conifers." Conifers "flower" too of course, but theirs are not considered true flowers....another example of a gray area in botanical classification. Anyway, I doubt that either Krussmann or Hillier ever encountered E. equisitina 'Blue Stem', whether we call it a conifer or not. Our website describes it as "An interesting conifer-related shrub with slender rush-like powder blue stems. Small orange-red berries sparkle delightfully in the blue foliage. Wonderful addition to a rock garden."

The adjective wonderful...again. Regular readers of the blog know that I use, and probably overuse the word. But I am sincere every time. Blue is wonderful, and the color is no stranger to the Flora Wonder Blog.

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