How to Plant, Grow, and Care for Microbiota Decussata

Looking for an alternative ground cover that’s reminiscent of juniper? Siberian cypress, botanically known as Microbiota decussata, is great. This evergreen, low-growing shrub has a wealth of garden uses.

Unlike junipers, it’s a bit more shade-tolerant. Its bright green leaves turn a coppery bronze in the fall, adding to its appeal. Spreading with ease, it will gradually fill in an area with lush color.

Though it was found in 1923, the world didn’t discover the shrub until nearly fifty years later. Since then, it’s become beloved for its feathery foliage and good looks. You’ll love it, too!

So let’s settle in and discuss this short little shrub and how best to incorporate it into your garden.

What is Microbiota Decussata?

In the spring, the Celtic pride plant’s foliage is bright, vivid green. As the seasons shift, this member of the cypress family becomes dark green in summer, then gradually turns to a bronze hue for the fall. It remains this color until the spring returns, and then undergoes a dramatic shift back to green.

Native Area

Mountainous portions of southeastern Siberia are where its native range lies. Because of political secrecy, the USSR did not share it with the rest of the world… at least for a while. Nearly fifty years after it was first named, it was revealed to the world at large as a medium maintenance planting.

Characteristics

Its foliage has a feathery shape. Each of the fan like sprays is comprised of many overlapping scale-like bits, giving it texture. These join together at the stem to create a fan or feather-like spray. Where juniper tips tend to curve up towards the sun, these branch tips gracefully bend downward.

While it does flower (especially in its native range), its flowers are ornamentally insignificant. From the spent flowers it forms its fruit. These are tiny spherical cones, each one covered in woody scales. They look like a brown berry from a distance, but the layering of woody scales on these berry like cones is visible up close.

It’s considered an evergreen conifer, as it does not shed bright green leaves in the fall. As it grows, newer growth appears over the older stems, overlapping old growth. Usually, it stays at a height of eight to twelve inches, but can spread anywhere from six to twelve feet in diameter. This makes is great for rock gardens.

Often this ground cover is used in foundation plantings on hillsides for erosion control. It makes an excellent lawn replacement in mass plantings. When combined with other evergreen plants, it can be quite striking. This is especially true in its fall coloration, as its dark bronze stands out from greener shrubs.

This lovely shade tolerant shrub is easy to grow, and won the Royal Horticultural Society Award of Garden Merit, too!

Planting

To grow it successfully, plant it in a location with well-draining soil, as it prefers slightly acidic to neutral pH levels. While it thrives in partial shade, it can also tolerate full sun in cooler climates. Ensure the planting area is free of weeds, and space the plants about three to five feet apart to allow for their spreading habit.

Water regularly during the first growing season to establish deep roots, then reduce watering as the plant is drought-tolerant once mature. Mulching around the base helps retain soil moisture and suppress weeds.

How to Grow

Conifers like Microbiota decussata tend to be pretty self-reliant, needing medium maintenance from humans. This one is no different in this regard! Let’s talk about setting up for success. With the right start, it will provide living color for you for years to come.

Light

While creeping juniper prefers full sun conditions in its native range, Microbiota decussata enjoys partial shade, and is fairly shade tolerant. In fact, that’s where it grows best. While it can tolerate full sun conditions in cool summer climates, it’s easiest to plan for some cover. It can grow in full shade, but performs best if it gets at least a little sunlight.

Water

Your conifer with its fan like sprays will enjoy consistent moisture, but it doesn’t like standing water. Keep the soil evenly damp, but not soggy to avoid problems, like root rot. Once established, tit is very drought-tolerant. Its roots can pull moisture from deep down.

I prefer a slow, gradual irrigation method for this conifer. Knowing how to use a soaker hose, and placing one beneath your plants when they’re young is best. This allows the moisture to ooze into the soil and thoroughly permeate. Water only when the soil is dry at the surface, but do a long, slow watering to soak the soil to six inches down.

If your climate has humid summers, be sure that your plant has some shade during the hottest parts of the day. The combination of humidity and heat in humid summers can slow down its growth. Night humidity isn’t a concern.

Soil

Moist and well-drained soils provide the best growth for your cypress. These plants can tolerate poor soils, as well as dry and thin ones, but they will grow quickly in loams. Rock gardens are perfect spots for your Microbiota decussata.

When possible, provide a rapidly-decomposing mulch like mulched dry leaves around new plantings. This helps to keep the soil moist and protects it from erosion. Once the plant has established itself and expanded in size, it will act as a living mulch.

In winter, a wood chip mulch will protect the roots from cold damage. Poorly drained soils will cause problems, so avoid planting in poorly drained soils.

Temperature

Zones 3-7 are where it grows best, and this is where it will thrive in full sun. It’s been known to survive in limited plantings in zones 8 and 9, but must be fully-shaded. It’s very cold-hardy, making it perfect in areas with chilly winters.

However, the opposite is not true of Microbiota decussata. Hot summers are a no-go, and the plant will die if exposed to heat or full sun in these areas for too long.

Fertilizing

If you plan on fertilizing, it’s best done in the early spring before new bright green growth appears. Use a balanced, slow-release fertilizer, preferably a granular form. These are easy to spread around the base of your plants.

Don’t feel as if it’s a necessity, though, it is quite tolerant of poor soil nutrition. It’ll survive even without fertilization. If your soil’s fairly rich, you can skip it with no problem.

Maintenance

Prune in the early spring, focusing on the tips of branches. Be sure to prune before the plant begins to green up again. This annual pruning encourages bushier growth habits.

You may also prune to ensure it remains in its intended growing area at any time. When pruning, be sure to use clean pruning shears to make a clean cut. Don’t use a weed whacker or edger, as this can cause potential damage to the rest of the stem.

Propagation

Propagation for Microbiota decussata is mostly done via stem cuttings. To take a cutting, select a healthy stem and cut it with sterilized pruning shears. Rooting hormone can help speed root development. Keep the cutting in moistened potting soil until it develops roots. Humidity around the young cutting can help keep it vigorous.

Seeds also form in the plant’s berry like cones, but these are slightly less reliable. When the tiny berry like cones begin to open, you can shake the seeds free into a paper bag and then soe seeds shallowly and keep the soil moist until a young plant has developed. A greenhouse cover and a seedling heat mat and thermostat are useful for germination.

Common Problems

You might be surprised at just how care-free growing Microbiota decussata will be. It handles most of its own needs, with only minimal care from you. But what of problems you might encounter? Let’s talk about those.

Growing Problems

Overwatering is likely the riskiest situation for your conifer. It just can’t tolerate standing water, which is why it thrives in rock gardens. The roots will suffer if you overwater, and it can cause major problems. The same goes if you don’t use well-drained soils.

Hot climates, and those with humid summers can be very, very tricky for Microbiota decussata. While it is possible to grow it in hardiness zone 8 or 9, it really needs to be in full shade rather than full sun. The heat of direct sunlight in those warmer regions can be deadly to the plant. Generally, it prefers cool summer climates.

Don’t panic when your plant starts to turn bronze in the winter, it’s a normal progression and it will green right back up in the spring again. Mulch around the base with wood chips to keep the roots insulated from cold.

Pests

Unlike many other ground cover junipers, Microbiota decussata is essentially pest-free. At most, deer may nibble on exposed foliage for food during a snowy winter but it’s not their preferred food, and they’ll choose alternatives whenever possible.

While pests don’t attack the plant, it can house pests. Mice may be discovered living in burrows under this and other ground covers. Some spiders find it to be a good home, too.

Diseases

Like pests, diseases don’t typically strike. It’s immune to many types of disease. Damaged roots may rarely be susceptible to bacterial or fungal root rots. Similarly, damage to the base of the may leave it open to bacterial infection, but it’s pretty unlikely as a whole.

Frequently Asked Questions