How to Grow Hypnum Moss (Hypnum cupressiforme)

Hypnum moss is a common type of sheet moss with tonnes of utility. 

It grows in dense sheets, so it’s a natural fit for ground cover in terrariums and gardens alike. Plus, it’s great for covering branches and rocks, just as it would in the wild. 

The creeping stems form the mat structure, which is then covered in overlapping leaves – giving the appearance of a cypress tree (hence the nickname, “Cypress-Leaved Plaitmoss”).

Naturally, Hypnum cupressiforme is actually found all over the world, so you can be confident it’s going to do just fine in a variety of terrarium environments.

Find out how to get this versatile moss to flourish!

Lighting

Hypnum cupressiforme grows best in shaded areas, with the kind of soft dappled light that finds its way down to the forest floor in its native environment.

That’s what makes it such a popular ground cover choice in gardens too.

It’ll do well in bright indirect light and should also pair nicely with other low-light tolerant terrarium plants. Just keep it out of direct sunlight, as strong light can easily burn this delicate moss.

Watering

Hypnum Moss is more drought resistant than your typical terrarium moss.

It prefers not to be saturated with water. So where I’d typically give a moss a good soaking prior to putting it into a terrarium, I’d skip that step with this one. 

Just the occasional light misting should be more than enough.

I’d also recommend using purified water (e.g., rainwater or deionized water) where possible.

Hypnum Moss is incredibly good at absorbing chemicals, to the point where it’s actually used to monitor environmental pollution in different areas. So it makes sense that it can be sensitive to tap water, and the salts can add white steaks to terrarium glass anyway

Temperature & Humidity

Hypnum Moss grows well in warm and humid conditions, so in that sense, it’s a natural fit for closed terrariums.

However, it can be susceptible to rotting in low-airflow environments. So it’s arguably better suited to large tank-style terrariums with built-in ventilation than completely sealed terrariums.

Growth

As the ‘Sheet Moss’ term implies, this moss can grow a healthy, thick carpet.

Kind of like a swollen grassy lawn on the ground.

It’s technically a type of feather moss too, but the leaves are extra chunky and rounded at the tips, so it doesn’t quite have the “light and feathery” feel as, say, an Ostrich Plume Moss. This is a heavy-duty, hardy moss!

It’s a pleurocarp, so it grows mostly horizontally. It’ll only reach a few inches tall, making it perfect for lining the bottom of a terrarium.

Propagation

You’ll be happy to hear that Hypnum Moss will happily propagate through simple division.

Simply isolate it into patches (you can just tease/tear it apart), and they should each start a new moss colony.

In fact, for quicker mat growth, you can place a few chunks around a terrarium. That way, their outward growth meets in the middle and covers more ground.

Varieties & Similar Plants

The Hypnales family of mosses has many notable varieties and come in various beautiful colors.

For thick, golden-brown moss, check out Hypnum lacunosum. Alternatively, Hypnum imponens is another solid choice for ground cover too.

That said, Thuidium delicatulum is arguably the more popular type of sheet moss for tropical terrariums.