Cryptomeria japonica 'Radicans' / radicans Japanese cedar

Cryptomeria japonica 'Radicans' is a robust, fast-growing selection of Japanese cedar with columnar to pyramidal growth habit. It has dense, blue-green, feathery foliage that retains its color in winter with less bronzing than other Japanese cedars. After 10 years, ‘Radicans’ grows to heights of 30 to 40 feet (10-12 m) tall (sometimes up to 50 feet/15m) and 15 to 20 feet (5 - 6 m) wide. It is less prone to tip blight and leaf spot than other members of the species.

This cultivar originated in 1941 as a plant selected for the forestry industry in Japan. In 1941, Takenoshin Nakai (1882–1952) made a formal botanical study on the plant, hoping to be able to classify it as a specific variety of the species (Cryptomeria japonica var. radicans). Apparently peer revue determined that there was not enough distinction from the type to warrant such classification, rendering the results of the study synonymous with the typical species. "radicans" translates in "rooting" in the Latin language.

Cryptomeria japonica 'Radicans' — an attractive planting at a tree farm in South Carolina.
Photo by Fast Growing Tree, inc.

Comments

Maureen

How deer resistant is the tree, is it partial shade tolerant and what is the approximate rate of grow per year?

Maxwell Cohn

Deer-resistance completely depends on the deer in your area. In my world (WA-state), deer never touch cryptos ... in the Northeast where there are more deer than food for them to eat, everything is fair game. Young plants are particularly susceptible to buck-rubbing, because the trees are straight and narrow when young.

This cultivar is tolerant of light shade, but might grow a little slower if not in full sun.

'Radicans' is selected in Japan for use in forestry. This implies really fast growth. I would not be surprised to see this one grow 2-3 feet per year.

Tj

I planted 15 Cryptomeria over the last 6 years and in Pennsylvania. The deer seem to eat some of my Cryptomeria and the past year rubbed the heck out of two new (8 ~ 10) feet tall Cryptomeria. I put fencing around them to stop that and repaired the massive damaged caused by rubbing.

Mike

This variety is always described as a maximum height of 30-40ft, maybe 50ft, but I'm wondering what its maximum eventual height might be many years later, for example in Japan (since even the variety was selected / developed there). Could it be this might be a 200ft tall tree in 500 years?

Maxwell Cohn

30-50 feet is a 10-year estimate. If a plant is healthy and happy with its surroundings, there's no reason why it won't grow 3 to 5 feet a year for a century or two.

Malcolm

What about pruning? Can Cryptomeria japonica var radicans be pruned? Let's say, to make it more columnar and less pyramidal? If so, what's the best technique to use?

Maxwell Cohn

no way ... grows too fast. You'll wear out yourself and your equipment. Best technique for you is to select a slower growing cultivar.

Darrell Wheeler

Can it be planted in the northeast in December, or wait until spring?

Maxwell Cohn

that's a really tough question! It's always best to plant in accordance with temperature, not time. Best results will be when air temp during the day is in the 50sF with nights dropping into the 30sF, with the ground not anticipated to freeze for 45 days. The goal is to not have any push of top growth until roots can develop. This is why spring is almost never a good time to be planting trees.

Where I live, the second week of October is usually ideal, on average. I only plant things in the spring that I'm not interesting in seeing live for very long. Nothing I've ever planted in December lived until the following fall. I guess too much opportunity for roots to rot.

Darrell

I’m north of NYC. So based upon your answer I had better wait. Thanks for the quick and detailed response.

Andrea

Hi,
I just ordered 16 of these in a #7 pot with the understanding that they can handle wetter soil. Is this the case? If not do they spread a shallow but wide root system so that a small berm would work?

Ronald Schlak

If my planting spot is on the moister side , I always try to plant shallow .
A small berm always helps

Andrea

Thank you. What size of a berm would you recommend, 1'x4' enough? Do you know how deep the roots typically grow? Thank you!

Ronald Schlak

berm sounds good
Most roots grow in the top 8 in. of soil
if you get the crown of the plants up , they adapt pretty well

David

I have a gravity septic system with a leach field and am concerned with the root system. I have read that cypress trees are dangerous near leach fields. What is the recommendation for planting near the field? What is the root spread distance for this tree at maturity?

Maxwell Cohn

root systems on trees spread to the outer limits of the drip line +10% ... People normally don't plant trees close to their leach fields.

Mir

CRYPTOMERIA JAPONICA ‘RADICANS’
Blue Green Japanese Cedar

Could a person cultivate a high branching Radican shape?

Maxwell Cohn

yes. All you need to do is remove the lower branches as it grows.

Nora Sadler

Is C. 'Radicans' as hardy as C.'Yoshina'

Peter Strobili

yes. Definitely. The only cultivars that are a little more tender are the juvenile-foliage selections.