Microbiota

( mi - kro - bi - OH - ta )

At-A-Glance Information

This genus of evergreen shrubs, commonly called Siberian Carpet Cypress, Celtic Pride or Russian Arbor-Vitae, is native to the Siberian Mountains and is suited for growing in UDSA hardiness zones 3-7 or Sunset growing zones A3, 1-10 and 14-17 (to find your zone, click here: Zone Map). There is only one species in the genus Microbiota, which is a member of the plant family Cupressaceae. Plants in this gens are closely related to those in Thuja (Arborvitae), Chamaecyparis (False Cypress), and Cupressus (Cypress). Plants need partial shade in warmer climates and moderate water for best performance. These ground-huggers have a neat, sprawling habit and reach 1.5 feet tall and 7-8 feet wide at maturity. Branches are horizontal and trailing. Foliage is green in summer, purple-bronze or reddish-brown in wintertime. Cultivars include 'Fuzz Ball' (with a softer texture, to 3 feet tall and 4 feet wide), 'Drew's Blue' (with blue-tinted foliage), 'Jacobsen' (with a dense habit and rich green leaves), and 'Celtic Pride' (with improved resistances and olive-green foliage). 

Caring for Microbiota

Plant Microbiota shrubs in a space in the landscape that receives full sun; ideally, they appreciate between 6 and 8 hours of sun each day for the best blooms. Provide shelter from high afternoon temperatures and too many hours of direct sun; these elements will burn the plant and damage foliage. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 5.0 and 7.0 (acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention.

Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered drought tolerant, but perform better with regular waterings. A good rule of thumb is to deep water these shrubs at the base when the top inch of soil feels dry, saturating the soil so that it becomes wet at least 6 inches down. Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season. The best time of the year to prune for shape and size is in springtime, before new foliage pushes out for the year. Take care to not cut back these shrubs too harshly, as they will typically not re-sprout green growth if old, brown wood is taken off. These shrubs can live for 25 to 30 years in garden cultivation, and have a natural life span of hundreds of years.

Propagation

The most straightforward way to propagate these shrubs is via taking cuttings and rooting them. For information on how to complete this process, read over the instructions below:

Propagating Microbiota by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth on your propagated Abutilon, you'll know you have roots. 
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Problems and Pests

These shrubs are generally pest and disease-free in the landscape, but they can suffer from time to time with issues with the following:
  • Root Rot
For more information on this issue, including how to treat and prevent it, consult the following pages:
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Gallery

The fruit on these shrubs come in the form of cones that appear after flowers have faded.
These ground-huggers are wonderful when planted underneath trees where they can receive filtered light.
Microbiota decussata is great for planting in rock gardens.

Videos

An informational video on this great species.
How to identify Russian Arborvitae.
See Microbiota decussata featured in this video about low-maintenance groundcovers.
All about Siberian Cypress plants.

Resources

Beloved Conifer: Microbiota decussata
Microbiota decussata: Shrubby, Low-Growing Groundcover
Wikipedia: Microbiota decussata
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 443, Microbiota decutassa