Shell Cypress, Obtusa Nana – Planting, Care and Pruning

In general, the mussel cypress needs a moderately sunny or semi-shady location that is somewhat sheltered. A spot with moving shade provided by a house, hedge, or other surrounding vegetation is ideal. Cultivated as a container plant, mussel cypresses can also stand on east, south or west balconies.

In addition, when choosing the location, it must be considered which Obtusa Nana breeding form has been chosen. Some sub-varieties are just 20 cm high, others reach heights of 4 meters. It is therefore worth taking a close look and planning for the long term.

Substrate

In order for the mussel cypress to thrive, it needs a fresh and unused substrate. This should be rich in humus and permeable, i.e. not tend to compaction and only moderately store water.

Fresh, high-quality garden soil is ideal. If this is very heavy and dense, it can be mixed with sand, coconut fibers or coarse grit to loosen it up. A generous addition of compost is also recommended.

plant

Before the mussel cypress is planted, a sufficiently large hole should be dug. The size of this depends of course on the size of the young plant.

It is better to make the planting hole twice or even three times as big as the Obtusa Nana actually needs. The excavated soil should be mixed with as much compost as possible and, if necessary, sanded.

After inserting, only the substrate has to be pressed down or stepped on and the plant generously watered. If you want to avoid frequent watering, you can also apply a thick layer of bark mulch to the tree disc. This reduces evaporation and prevents the soil from drying out.

maintenance

The care of the mussel cypress is very simple. Watering only needs to be done as needed, occasional fertilizing and pruning can be beneficial – but this depends on substrate, location and plant.

pour

The Obtusa Nana tolerates neither waterlogging nor drought. When it’s dry, brown spots or dead shoots show up very quickly, and when it’s waterlogged, fungal infections have an easy time.

It is therefore advisable to find a balance and keep the mussel cypress slightly moist but not wet at all times. As soon as the top layer of the substrate dries, it can be slightly refilled. In the case of mussel cypresses in tub culture, watering is of course necessary more often than with plants that are free in the garden. The same applies to very sunny locations.

The softest possible irrigation water should be chosen for watering. Collected rainwater or stagnant tap water that is low in lime is ideal.
In case of rain, however, this can be waived.

Fertilize

Anyone who has applied bark mulch to limit evaporation has also contributed to the fertilization of the plant. Because the nutrients from the mulch inevitably go into the substrate and thus into the roots of the mussel cypress.

Nevertheless, it may be necessary to provide the mussel cypress with additional nutrients.

With a sufficiently prepared substrate that has been mixed with compost or, in the case of coniferous soil, has been pre-fertilized, fertilization is only necessary from the second year of growth.

Then you should fertilize for the first time in February or March and add more nutrients again in midsummer.

This can be done with compost, which is lifted under the substrate and then watered abundantly. As a simpler alternative, conifer fertilizer can also be chosen directly, which is poured in liquid form or used as a dry long-term fertilizer.

However, the second application of fertilizer should not take place later than August or September. Otherwise, the evergreen tree will grow too late and can no longer adequately prepare for the dormant phase in winter.

To cut

Pruning the mussel cypress can be easy or dangerous for the plant. The decisive factor here is whether it is a drawn or refined form.

If this fact cannot be found in a tree nursery or garden center, the trunk should first be checked carefully. If there is a thickening relatively close to the surface of the earth, the mussel cypress has been grafted. So here a noble branch was placed on a related wild instinct. Another visual clue can be found when the structure of the bark changes abruptly at a straight point.

In the case of the refined shapes, it is important to cut them as gently and carefully as possible. If too much is cut off, the wild form can take over. This is expressed in the fact that suddenly a clearly defined, usually straighter and less decorative branch shape grows out of the Obtusa Nana.

So very little, if any, should be trimmed and blended here. Normally, however, not even that is necessary, because the mussel cypress grows straight and dense – even without external intervention.

This problem does not occur with extruded shapes that have not been refined. They can therefore be blended without hesitation. In any case and with any form, the following points must be observed:

• Use only clean and if possible disinfected cutting tools
• Choose spring or autumn as the time for cutting
• Better regularly and little than cutting away a lot at long intervals
• The smaller the plant, the gentler it is to blend
• Rub interfaces with a little water to protect the plant

Under no circumstances should be blended in blazing sun. Because in this fresh cuts would burn or dry out within a very short time and then turn brownish.

propagation

To propagate the mussel cypress, either the lengthy and cumbersome rooting of a cutting is necessary or the refinement.
Both variants are not easy, require patience and sure instinct.

Propagation by cuttings

After pruning in spring or autumn, the cuttings can be used directly as cuttings. Spring is ideal. The cutting point should be as large as possible, so an oblique, diagonal cut is ideal.

Immediately after cutting off the mother plant, the cuttings must be provided with root aid. It makes sense to place the cuttings prepared in this way in moist potting or coniferous soil and to spend them in a bright location. After cutting in the spring, the cuttings can remain outside. The chances of root formation are significantly greater. But also not guaranteed.
If this form of propagation takes place in the fall, you have to bring the cuttings inside. A stand on a bright window sill is ideal here. Normal room temperatures are optimal.

In any case, the substrate should be kept evenly moist but not wet. Even then, the chances of successful root formation are rather low.

Increase by grafting

Propagation through grafting is safer but also not equipped with a guarantee of success. This requires a wild cypress as a base. This is beheaded about a hand’s breadth above the root.

A shoot of comparable size is grafted onto this base. To increase the chances, the addition of special growth hormones is recommended. The closure around this contact point is made with special wax or fabric.

However, growth is not guaranteed here either. In addition, the grafting alone is a real challenge, requiring a sure instinct and some knowledge.

hibernate

Although the mussel cypress is evergreen, it is only partially winter-hardy and frost-hardy. In very hard and cold winters, separate protection is therefore advisable, but it does not have to be too extensive.

Normally it is sufficient to provide the plant with brushwood at the base and to wrap the trunk and head with garden fleece. However, this only applies to mussel cypresses that have been planted freely in the garden.

Plants grown in tubs need more protection. The easiest way is to bring the container and plant inside. Here the Obtusa Nana should be bright and cool but completely frost-free. A well-insulated room in which the thermometer does not climb higher than 15 °C is ideal. For example, an unheated conservatory, a hallway, a basement room or a garage.

Typical diseases and pests

The greatest enemy of the Obtusa Nana is rot. This occurs when the mussel cypress is too damp and too cold. The fungi attack the roots and decompose them, so the growth is cut off from the supply.
In order to save the mussel cypress in this case, you have to dig it up and free it from the soil as thoroughly as possible. The roots should be rinsed off. The planting hole should be dug generously and filled with fresh soil. Roots that are already greasy should be cut off.

Of course, it’s best not to let rot develop in the first place. The mussel cypress should never be exposed to waterlogging. And especially in the cooler seasons, care must be taken to adjust the watering quantity and ensure good drainage.

On the pest side, aphids, moths and mites can become dangerous. However, they appear much less frequently on the conifers and can be treated with appropriate pesticides without any problems. Natural remedies can also help. For example, for smaller Obtusa Nana that are cultivated in a tub, a solution of solid soft soap and water is ideal, with which the mussel cypress is sprayed and then rinsed off. The solution must not get into the substrate.

With larger trees that are in the garden, however, this is more difficult. A nettle manure can be used here, which is used for spraying and watering.

Is the mussel cypress poisonous?

As beautiful as the mussel cypress is to look at, unfortunately it is just as poisonous. This applies to all parts. So for leaves as well as for bark, flowers, fruits and roots.

The Obtusa Nana is therefore not suitable for rabbits or guinea pigs to run free, as they will inevitably gnaw on it. Likewise, other pets, such as cats or dogs, and small children who may bite the mussel cypress or tear off parts while playing, must be kept away from it. Because even a slight contact with the escaping plant sap can lead to symptoms of poisoning. This includes:

• rashes of the skin
• ulcers
• nausea
• Vomit
• diarrhea
• chills
• dizziness
• a headache
• fever

If you don’t want to or can’t part with the mussel cypress, you should at least fence it off and thus ensure a safe distance between your children and animals.

In addition, it makes sense to wear gloves when blending.

Conclusion
The mussel cypress or Obtusa Nana, as it is also called, is an easy-care and particularly decorative plant. However, the cut can be a challenge and therefore requires some caution.