Friday, October 5, 2012

The Conifer Blues

The conifer hill at Hillier's Arboretum

Conifer blues? Do conifers give Buchholz the blues? No, no...I'm not down on conifers at all; well, I mean I am down in the modern sense of the word. Ah, this isn't starting well.

How about: Today's web log will examine and celebrate coniferous trees with blue foliage. That's better.

My horticultural career began nearly forty years ago, and I worked for a large nursery that factorially produced Rhododendrons, Alberta spruce and a slew of junipers. The limitations in product line didn't bother me then, as I was new and all plants were fabulous. One plant was different though, because it was a tree, not a shrub, and that was the "Blue Atlas Cedar," Cedrus atlantica 'Glauca'. The small trees were narrow and sparsely branched, and that was the "alpine-like" charm of them. Later I realized that they grew to enormous size and were wide-spreading, and that planting one next to the house was not a good idea.

"Glauca" is from Latin glaucus or glaucum, referring to a white coating on the leaves. My Atlas cedar appeared to be blue, and yes, on close inspection it also appeared to shine with white. However, one could rub off this blue, and during one particular cold snap with strong winds, the blue disappeared on the side of the trees bearing the brunt of the storm. In some climates this is an annual event.

Cedrus atlantica 'Glauca Pendula'

Now I don't grow Cedrus atlantica 'Glauca', and I have only a couple of the 'Glauca Pendula' around. The reason they were discontinued is simple: it's because of you--it's your fault. You stopped buying them. But just as well, as you have shifted your preference to more dwarf forms which are just as blue, or just as glaucus.

Cedrus atlantica 'Sapphire Nymph'

Cedrus atlantica 'Sapphire Nymph'

Cedrus atlantica 'Sapphire Nymph' is one such dwarf. The needles are silvery-blue but the new growth is creamy-white. It glitters, like I guess a sapphire should. You can decide for yourself if it is a nymph -- I could write an entire web log on the mythological and popular connotations of the word, but it is a name I would never use for a plant. Of course the "nymph," or nympha, could refer to a larval stage of certain insects which can resemble the adult, only smaller, as 'Sapphire Nymph' does resemble the atlantica 'Glauca', but grows to one percent of the latter's size. 'Sapphire Nymph' grows low and spreading, naturally, or it can be staked into a dwarf pyramidal tree.

Cedrus atlantica 'Horstmann'

A new cultivar of blue Atlas is 'Horstmann', from the famous Horstmann Nursery in Germany. It grows at half the rate (or less) as atlantica 'Glauca', and the needles are far more short as well. It should be grown in full sun for best blue color, and will attain 7' to 8' tall by 3' wide in ten years. And thanks, for you do continue to buy this cultivar from me.

Cedrus atlantica 'Blue Cascade'

A mounding selection of some interest is Cedrus atlantica 'Blue Cascade', and its needles are more blue than 'Glauca Pendula'. It is staked to the preferred height, be it 6' or 10' or more, then topped. Eventually the side branches will descend, and you're left with a dense blue haystack. It seems like at least one branch would continue to shoot upward but none do. Where space allows, 'Blue Cascade' makes a fantastic lawn tree.

Cedrus deodara 'Karl Fuchs'
Cedrus deodara 'Eiswinter'

Cedrus deodara 'Electra Blue'

Now to the Cedrus deodaras. The fast-growing blue cultivars tend to have narrow shapes, and they are known to be more cold-hardy, for they originate in the mountains of Afghanistan, Pakistan and India. 'Eiswinter' (Ice Winter), 'Eisregen' (Ice Rain) and 'Karl Fuchs' are three popular clones. 'Electra Blue' is the most blue, or shiny; also it is more fat and dense. Apparently it was selected by the late Dick Bush of Oregon, and some still refer to it as 'Bush's Electra'. When Bush gave me a start twenty years ago, however, he called it 'Electra Blue'.

Cedrus deodara 'Devinely Blue'

Cedrus deodara 'Feelin Blue'

Cedrus deodara 'Feelin Blue'

Cedrus deodara 'Devinely Blue' makes a cute miniature tree if staked. Short branches will arch downward in time. If left unattended, i.e. unstaked, it will grow more broad than tall. But perhaps a better selection is 'Feelin Blue', a dense prostrate spreader, which looks great in a small garden or arching over a wall. It too can be staked, and then will develop into a narrow weeping tree. 'Feelin Blue' originated as a seedling in a Boskoop, Holland nursery, and was introduced in 1986. Winter cuttings of both of these dwarves root easily, or they can be grafted onto Cedrus deodara rootstock.

Sequoiadendron giganteum 'Glaucum'

Sequoiadendron giganteum 'Glaucum' at Bedgebury Arboretum

I look out the office window and the tallest tree in the original Display Garden is Sequoiadendron giganteum 'Glaucum'. Fortunately it forms a narrow spire, and so is permitted to remain in the rather overcrowded garden. The most impressive specimen of 'Glaucum' must be the giant growing at Bedgebury Arboretum in England, which I could spot from half a mile away. I propagated 'Glaucum' twenty eight years ago by grafting, and it has already surpassed two older Picea abies seedlings. At the time I was simply looking for stature, for size, for relevance in this garden; perhaps just a tree to piss behind.

Sequoiadendron giganteum 'Powder Blue'

Acer circinatum 'Burgundy Jewel'

Sequoiadendron giganteum 'Powder Blue' grows a little more wide than 'Glaucum', but it is aptly named and the foliage shines, even on inner branches. Gordy Halgren of Peacedale Nursery in Washington state discovered 'Powder Blue' as a neighborhood specimen and introduced it into the trade in about 1996. Don't forget Mr. Halgren's other major find and introduction, the excellent Acer circinatum 'Burgundy Jewel'.

Sequoiadendron giganteum 'Little Stan'

Sequoiadendron giganteum 'Little Stan' is a miniature "Giant Redwood" with gray-blue foliage that remains juvenile. We have best success rooting 'Little Stan' rather than by grafting. Our website lists it as hardy to -10 degrees F, USDA zone 6, but that seems optimistic. It is not nearly as hardy as the vigorous upright selections.

Tsuga mertensiana at Mt. Rainier, Washington

I can think of no hemlock species or selections with blue foliage except for the "Mountain Hemlocks," Tsuga mertensiana. The species mertensiana is from western North America, and in my state of Oregon, it can be found at high elevations, often in the alpine zone. Since childhood I have visited these wonderful trees, and I'm comfortable around them as I would be with friends. Each one is different, but you often see them grouped as families. Normally they are slender with branches arching downward. At high elevations they can assume a Krummholz position, hunkering down against the elements.

I admire the young "Mountain Hemlocks" the most. To quote Peattie in A Natural History of Western Trees "Long and slender, the arms are held out like a dancer's, and the smaller branches curve gracefully out and away and down, like the fingers of a hand extended but relaxed, and all the twigs are clothed in the bluish green of the softly shining foliage." Also, "A young Mountain Hemlock is all feminine grace..."

Dr. Lewis (left), Dr. Bump (right) with Tsuga mertensiana 'Bump's Blue'

Tsuga mertensiana 'Bump's Blue'

We have introduced a couple of intensely-blue mertensiana cultivars, 'Bump's Blue' and 'Powder Blue'. Dr. Bump of Forest Grove, Oregon discovered an outstanding seedling on Mt. Hood, and brought it back to his garden. I saw it at twenty to twenty five years of age and was impressed. I took cuttings and eventually named and introduced it as 'Bump's Blue'. We also grow the European selection, 'Blue Star', which is also very nice, but it is no more blue than Dr. Bump's wonderful find.

Tsuga mertensiana 'Powder Blue'

'Powder Blue' was our seedling selection, and its foliage is a more light-blue than those mentioned above. All are very slow-growing, whether propagated by rooted cuttings, or by grafting onto mertensiana rootstock. So they're not highly profitable for the grower, but I've never had too many either, and true connoisseurs of conifers can't resist them. They are very popular in our pumice stones and pumice gardens.

Picea glauca 'Blue Tear Drop'

At least three species of Picea feature blue cultivars: engelmannii, glauca and pungens. Picea glauca 'Blue Tear Drop' is a cutie that is aptly named. Picea glauca is a tough species, hardy to USDA zone 1 and easy to grow, and 'Blue Tear Drop' is a neat little dwarf that's useful in many garden situations, or excellent in a container.

Picea engelmannii 'Bush's Lace'

Picea engelmannii 'Bush's Lace' is a bright-blue weeper, introduced by the same plantsman who brought us Cedrus deodara 'Electra Blue'. It is usually staked when young, and it will grow fast and narrow. At maturity, however, it broadens into a full dense mound, and should be sited with adequate room. I like 'Bush's Lace' and we sell a fair number, but I don't see why "lace" got worked into its name.

Picea engelmannii 'Blue Magoo'

Picea engelmannii 'Blue Magoo'

Our selection of engelmannii is 'Blue Magoo', which arose as a seedling about twenty years ago. It is a good blue, but a little more dark than 'Bush's Lace'. 'Blue Magoo' appears most graceful in spring with a flush of drooping new growth. In fact, it is a sight to behold. Later in the summer, the branchlets harden and ascend, as you can see in the photos above. Small purplish-red cones are attractive in spring, then they ripen to light brown. Engelmannii is tremendously hardy -- some suggest to -60 degrees F, USDA zone 1.

Picea pungens 'Coors'

Picea pungens 'Continental'

The Picea pungens species is well-known for many blue cultivars. 'Continental' is one of the very best for excellent color and form. Trees shape up in the field like perfect Christmas trees, with very little staking or pruning required. 'Coors' is more slow and awkward when young, but it too will develop into a formal pyramidal shape. 'Coors', found on the Coors estate in Colorado, is known as a "shiner," i.e. its foliage is more glittery white than the deeper true-blue of 'Continental'.

Picea pungens 'Lucretia'

Picea pungens 'Blue Pearl'

Picea pungens 'Blue Moon'

Picea pungens 'Lucretia' displays the same true-blue of 'Continental' except that it is a dense dwarf spreader. I think 'Lucretia' is an improvement over the ubiquitous cultivars 'Globosa' and 'Montgomery'. 'Blue Pearl' is more dwarf than 'Lucretia', while 'Blue Moon' is the most tiny of them all.

Picea pungens 'The Blues'

Picea pungens 'The Blues'

Coming full circle, I'll end today's web log with "the blues" again, but in this case it is the cultivar Picea pungens 'The Blues'. Larry Stanley of Stanley and Sons Nursery discovered a branch mutation on another pungens cultivar, a mutation that dropped downward. Stanley propagated the shoot and staked it, and eventually found that all the side branches would droop downward. The grower can produce a narrow weeping tree by continuous staking; or if staking is abandoned, the leader will eventually wander sideways, and the result will be something like the photo above. In my opinion I think 'The Blues' is among the very best of all conifer introductions, and Stanley deserves a lot of credit for recognizing its potential. I'll bet that the majority of growers would have pruned out the freak branch instead of propagating it.

We'll continue next week with more blue conifers, for there are still many excellent choices. And I hope that you'll have sweet blue dreams in the meantime.

Blue conifers in the landscape


  1. Picea mariana 'Blue Tear Drop' is a cultivar of Picea glauca not mariana. This is per the founder, Bob Fincham.

    1. Are you aware that he did in fact write glauca instead of mariana?