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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.

  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.

    1. margaret 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. Christine 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!)

    1. margaret 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.

    1. Laura says:

      A landscaper planted 5 of them in a sloping but small bed to help hold the soil and mulch 5 years ago. Washington DC area, Zone 7, sun all day until late afternoon. One died the first season, was replaced and that one died, too. The rest spread at first but gradually died off. Not the winter bronzing, but dead. Pruning off the die back did not save the plants and I finally had the remaining ones dug out today. I don’t know what killed them. The sun and heat? The mulch? Too crowded for the size of the bed? Perhaps it is some unidentified disease, but the perennials in the bed are very happy. I love this plant. Great winter and summer color, soft needles, graceful form. It looked great spilling over a low wall. But I don’t think I’d chance it again without knowing how to keep it alive.

  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.

    1. margaret 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.

    1. Margaret 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.

    1. Margaret 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.
    But.
    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

    1. Margaret 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. :)

    1. Margaret 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.

    1. margaret 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:

    Hello
    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?

    1. 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.

      1. 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.

  14. Jenny says:

    I am a landscape designer and have planted Microbiota many times without issue, in both shade and sun. It’s so deer resistant in the Baltimore area where deer are a huge problem. I have also been so pleased with this plant in my own garden. Until now. I planted 25 ‘Celtic Pride’ along the front foundation of a house 2 months ago and at least 7 are dead, more have yellow branches. The plants are yellow, but still alive — very well rooted! The client is doing an excellent job watering. Everything else is thriving including the transplants. Very disheartening to say the least.

    1. margaret says:

      I had the same experience with half of my plants years ago, Jenny. I am told that since then more disease-resistant varieties have been introduced…and Celtic Pride is one of those with resistance bred in. Uh-oh.

  15. robert gardner says:

    I have just gotten my first Microbiota decussata plants. I am going to try and make a Bonsai out of it.
    It has such wonderful trunk lines and exfoliating bark. Have you heard of any of these as Bonsai, with their long graceful branches, awesome bark I thing that they will make a wonderful subject. They will be placed in a deep oval pot with lots of well draining soil. A good amount of Pumice, pine bark finds on time release fertilizer.
    Please feel free to answer this new project for me.

    1. margaret says:

      Hi, Robert. I don’t know about it as a bonsai, but I will say this: It is known for being inclined to dieback/browning of the tips of some branches, requiring regular removal of whole shoots, so I wonder if that would be a challenge with a carefully trained bonsai — to potentially lose bits to browning.

  16. Chris Tracey says:

    Hi Margaret,
    Over the last 2 years, i have been watching, both newly planted and long established (7+years)
    microbiota rapidly die off. Large, long limbs just turning off-green to yellow to brown with no apparent reason. My first thought was that voles, or some other rodents, were eating the bark/cambium at the base of the plants, but no. I really have no idea at this point, but i’m thinking that we may just be getting to warm, in the Boston area, for these siberian transplant to thrive.
    Chris Tracey
    Avant Gardens Inc

    1. margaret says:

      Mine, too — mine are very old plants, so not the newer disease-resistant varieties that are now offered that supposedly resist the grunge. Like Celtic Pride that I have read about. I was thinking that might be the issue…but as you point out nothing is like it was and the plants seem to know it acutely. The last 2 weeks I cut out about 10 long limbs from various plants. Talking about removing them altogether this fall. Guess I need to call some of the breeders and ask whether this is the “disease resistance” we need or another matter…

  17. Marie Tulin says:

    My husband just finished hacking out the largest of the three microbiotas left in the garden. I planted 5 of them at least 10 years ago just as they were becoming popular.

    The dead /dying branches finally defeated this getting-older -gardener. I don’t have the energy, hand strength or time to sit in the middle of a prickly plant and hand prune or lop off 1/4 of the plant each year.

    It’s too bad because it has a graceful, undulating texture at the edge of a big border. I hoped it would replace perennials and lessen maintenance. Alas, it’s susceptibility to disease is a fatal flaw.

    I’ll let others field test the supposedly ‘resistant’ variety. If the reports are good in 5 years I may try “new, improved” version. Meanwhile, looking for a lower maintenance edger.

    1. margaret says:

      I hear you, Marie. Some of mine just keep on ticking but one big one in particular keeps having bits go brown. Ugh.

  18. Barbara says:

    I need to transplant a couple of my Siberian Cypress. When is the best time to do so–when dormant? Just before spring growth? I love these plants and have many of them in my landscape under various light conditions. Per the advice above I will try to keep the dead leaves that accumulate off their centers.

    1. margaret says:

      Hi, Barbara. Don’t know where you live (what zone) but I like to allow things to get rooted in before my long cold winters here in the Notheast, so though I could try it I think I’d wait till earliest spring when the ground is workable again.

  19. Frances Koehlinger says:

    I have 3 of the microbiota decussata bushes in my front landscape. I noticed they’re turning brown underneath. Are they dying? Is there something I should be doing?

    1. margaret says:

      They get bronze-colored (almost purple-brown) in the winter cold…but if the foliage is brown/gold/tan and brittle, then those branches are dying and should be cut back or cut out. I cannot tell you what is up — I have had some thrive and some brown and die on the very same hillside bed over many years (like 15 or 20). Early on, there was an unimproved variety for sale that supposedly had less resistance to disease, and now most plants for sale are supposedly more resistant. I know that it hates poor drainage, like clayey or damp soil, and will get root diseases that presumably lead to dieback…so though it doesn’t want bone dry or sand, it cannot be in a mucky spot. Other than that…its behavior mystifies me, because as I say I have lost like every other plant in the same bed and had to try again.

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