beloved conifer: microbiota decussata

microbiota-by-wallF ILL IN THE BLANK: ___________ is an evergreen ground-covering conifer that can tolerate some shade and minus-30 or colder. I guess I gave away the answer in the headline, but you get the idea: It’s an unusual set of traits. And Microbiota decussata, the so-called Siberian cypress, distinguishes itself just a little further, turning a bronzy-purplish cast in winter.

microbiota-with-buddha-2Unlike the ubiquitous groundcover junipers, Microbiota is lacier-textured, almost Arborvitae-like, and arches in a somewhat graceful manner. My oldest plants are more than a foot tall at the tallest spots, and more than 8 feet across (I have read that they can get to 10 or even 12 feet wide and a couple of feet high). It is good for holding banks, which is how I use it on my hilly site in part shade, such as just above and beyond the pictured Buddha (if one can be above and beyond Buddha, that is).

The plant was first discovered near Vladivostok in the 1920s, above the treeline, where it survived the deep cold of Siberian winters, making it a Zone 3-hardy creature, supposedly.

Although it is a groundcover species, don’t expect it to grow in the dark: That was the mistake made at first when Microbiota reached the American market in any numbers maybe a decade ago. Saying a plant can handle some shade is different from saying it’s a shade plant; this one wants half a day of sun or more, I think, and wholesalers who propagate a lot of it say sun to part sun on their labels. In warmer zones, protection from afternoon sun is important, and in fact Microbiota isn’t a fan of the hottest zones at all.

microbiota-winter-colorThough Microbiota (seen above in winter color) is said to have few if any pest and disease problems, I will confess to this: I have killed a number of them, without ever learning why. What was meant to be a whole bank of Microbiota simply didn’t choose to be that way, and only about half of the ones I planted thrived.  In another spot, I had the same experience. Hmmmm…was it something I did, or had this load of plants suffered some insult or injury en route to me that didn’t show itself until later?

I will never know. (A familiar refrain in gardening: You often never know; the thing just dies.) I have read about a disease-resistant cultivar–but without much detail about what it’s resistant to, and whether that matches what happened to some of my former plants. Give Microbiota well-drained but not dry soil, more sun than shade, and remember: Though it won’t happen instantly, these plants get big, so give them room.

May 6, 2009


  1. Ted says

    Another great plant. I’ve planted them in several yards and either they do well or they fail miserably. They seem to have a bit of a Goldilocks complex. Moist soil with good drainage, but not too dry or wet. Bright light but not too hot.

    My best specimens are on the north side of my house where they get morning and afternoon sun in summer and shade all winter. The sandy loam soil is sloped, but they get extra water from the roof line.

  2. Abby Jane says

    I’ve found they hate having leaves on their branches over the winter. If the leaves aren’t completely removed, branches die.

    • says

      @Ted: Glad it’s not just me, but the *Goldilocks* thing at work. Thanks. :) Funny how some plants are just that way, isn’t it?

      @Abby Jane: This is a very good observation, thank you. I think I only semi-consciously realize that, and will be even more careful. They are in a windswept spot and leaves blow on again and off again all winter, so it’s tricky. See you soon!

  3. says

    I know it’s beside the point, but I have to say how reassuring it is to hear “the thing just dies,” even for master(ful) gardeners. I have been lamenting several inexplicable deaths this spring with a “why do I even bother?” attitude. New attitude: “Oh well, better luck next time!” (I am surprised, though, to hear that many gardeners keep planting “iffy” things. I am not very forgiving, it seems. One strike, two at the most, and you’re out!)

    • says

      Hi, Christine. Trust me, even the *real* experts (my mentors, and their mentors and their mentors’ mentors) lose plants every single year. I think 3 strikes is probably a fairer plan, if you can stomach it. So many variables at work: soil, rainfall, temps, how bad the winter is that year, what condition the poor things arrived in…and on and on.

  4. Marion says

    I have one that has been struggling in the same spot for about 20 years! It won’t prosper and it won’t die! Saw some out in Mill Valley, CA that were enormous! Never too hot in that area!

  5. Elizabeth says

    In the front of my house is a hill/slope that was planted with junipers — two varieties — about 20 years ago. One variety started to die off as the sunny slope became a shady place. (from the maple that was planted after the junipers and is growing above them). So, after two experts recommended the microbiota decussata as a replacement, I had them installed last summer. And, I LOVE them!! Love the way they look and that they don’t prick me. They are soft to the touch, a wonderful thing. So far they look good after their first hard winter, so I hope they stay healthy in this spot. Thanks for mentioning their dislike of leaves as that is a problem for me. I will have to try and keep them free of leaves next winter.

  6. Nancy says

    In the Washington DC area people avoided Microbiota because it would look good for a few years then start to brown out; many blamed our neighborhood’s heavy clay soil. When I moved to the Eastern Shore of Maryland (well-drained, sandy, acidic soil) I planted five in a shady site to offset the effects of our hot & humid summers. They looked great for about five years and now … two are dead and the remaining three continue to brown out. I’ll keep the leaves off this winter and see if that helps, but it seems this Eskimo will never be a southern belle.

    • says

      Welcome, Nancy. I guess I am not alone, and I am certainly in a much different climate than either of your trial grounds with Microbiota. Oh, my. Thanks for sharing your experience, and do come again soon.

    • says

      Welcome, Linda. I have never seen it listed as such, but that doesn’t mean anything certain. However, based on its native habitat it’s hard to believe it will love much salt. See you soon again, I hope.

  7. abby says

    Hi – I am a new gardener (my first year) and have planted 2 and just bought a 3rd to transition from some boulders down through a root heavy/acidic soiled slope that gets morning sun. A really basic question: how deep should I plant? Is it okay if the bottom branches touch the ground? We just got heavy rains on the east coast and these branches are muddy – I’m afraid of promoting rot or disease. Any ideas? Thanks.

    • says

      Welcome, Abby. A good question. The idea is to end up with the plant at the same level in the ground as it was in the pot — so the top of the former rootball (the big hunk of roots and soil you took out of the pot) should be approximately where it was before, maybe a tiny bit deeper but not much. In many low-growing or creeping plants, you are right: the branches will touch the ground, especially at first. No worry. Don’t bury them though. :) See you soon!

  8. Garden Coach Sheila says

    Yes, I love them, too. Much classier than Junipers in some gardens.
    They don’t seem to tolerate a snow load.
    I’ve lost a couple.
    My client’s brother in law told her to yank them out because they were brown.
    The copper colour was to accent the traceries in the fieldstone of your house front. Arggghhh

    • says

      Welcome, Sheila. Mine are currently under 2 feet of snow, as they often are in winter…but they seem OK. They are on a steep hillside; not sure what difference that would make, but just a note. I have lost some in the early going (when young) but the ones that survived thrived. And haha about the coppery winter color; I love it. :)

    • says

      Hi, Connie. So few things tolerate the allelopathic effects of black walnuts, so I wouldn’t count on it. I don’t even know where to look for info on that, though — sorry to say.

  9. Sandy Otton says

    I learned about Microbiota decussata in my Groundcovers course at Longwood Gardens. At that time (1993) the only pest/diseases listed in my workbook were, “Dieback of unknown origin”. I have a note that my instructor (Marty Kromer) had indicated that he loses 25 % of these when planting. I hope that helps you feel better about the plants in your garden that did not make it!

  10. Charlie benedick says

    Above and beyond the Budha is cracking me up! I read your posts as much for your humorous prose as educational ones!

  11. James Kay says

    I live in the middle of Missouri. In May 2006 I planted 64 Russian Cyprus on a 45 to 60 degree slope (15 feet x 80 feet) at the front of my home as ground cover. These were in 2″ x 2″ by 4″ pots. Most of them grew OK but I would lose one here, another there every year. The summer of 2012, the slope was 90% covered with mature plants. I was away for two weeks during a dry spell and when I returned home all the plants had turned brown. This spring they did not green up so I am replacing them with Blue Rug Junipers.

    During the time I was losing a plant, here and there, I had the local extension service come to inspect the plants to see if they could find a reason they were dying. They could not and suggested I send a plant to the University of Missouri in KC. I never did.

    At the same time I planted the Russian Cyprus, I also planted (10) Blue Rug Junipers. These plants are in the same soil and sunlight. They all got the same care. The Blue Rug Junipers are all alive and doing well. I am now in the process of planting 128 of the Blue Rug Junipers where the Russian Cyprus once were.

    • says

      Hi, James. I think this is a case of when a plant gets into the market in bigger numbers before one of its drawbacks are realized. Apparently Microbiota (the straight species) was/is prone to some kind of tip dieback, and so recently (2010 I think) at least one disease-resistant cultivar was introduced that is not so susceptible. I think you and I started earlier than that so were guinea pigs! :) I have maybe 5 very happy, very large plants but did lose some in the process.

  12. Lucie says

    I have just purchased some microbiota for a slope similar to yours. What is the other plant used on that slope in your photo of stone wall with the Buddha?

  13. Steve Pinkston says

    Hi Margaret, great site. I will be visiting a lot. Last fall, I planted three, fairly large in a site of my deck. The spot is an old annual garden, so the soil is good. Two are doing well, with bright green color, but one is sort of grey green. We live in southeast PA, about 20 miles west of Phila., and our winter was particularly harsh. Would a feeding of Holly Tone give my grey friend a boost?

    • margaret says

      Hi, Steve. Hard to say. Sometimes they just die (as I mention) and I am not sure why. Is it also stiffer/drier? (If so, not good news, of course.) Holly Tone is slow acting so not going to do anything radical instantly, but thorough watering is probably even more important. Fall-planted things before a brutal winter can mean there was desiccation and damage more than with a well-established plant, and conifers and other evergreens are especially vulnerable.

      • says

        I’ll leave it in the ground, give it some Holy Tone and provide plenty of water. Maybe it will come around. The other two are doing great and will eventually cover the spot. Thanks for the info.

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