One of the greatest joys of keeping a planted tank (or any live plants in general) is to watch something that you take care of grow, thrive, and multiply! At some point however, your aquatic plants will be too overgrown and need to be trimmed, or maybe you'd like to propagate them to use in other projects or to farm them. With so many different types available, it can be a little overwhelming to learn how to trim each type of aquarium plant. 

In a broad sense, we can generalize most of the plants we use in the hobby into 6 broad groups: rhizome plants, stem plants, rosette plants, carpeting plants, bulbs, and mosses. That leads to the question: how do you trim, prune, and propagate the many types of live aquarium plants?

In this article, we'll review how to trim:

1. Rhizome Plants

2. Stem Plants

3. Mosses

4. Bulb Plants

5. Rosette Plants

6. Carpeting Plants

Rhizome Plants

Most epiphyte and rheophyte plants that we use in the hobby fall under the this category. Some examples are Anubias, Microsorums (Java fern varieties), and Bucephalandra. The rhizome of these plants are a thick modified stem in which the roots and leaves grow from.

It's important to note that the rhizome should never be planted in substrate. Instead, epiphytes can be attached to driftwood, rocks, or other hardscape. The rhizome itself must never be buried because it will prevent air or water to adequately flow across the rhizome, which will cause rot and ultimately, death of the plant.

When is it time to trim a rhizome plant?

Unhealthy, rotting, or browning leaves should always be trimmed off so that the plant can focus its resources and energy into new leaves and healthy parts. When trimming a leaf, make sure to cut the leaf off as close to the rhizome as possible.

The roots that come from the rhizome function as anchors for the plant to attach itself to wood and rock surfaces. When these holdfast roots become overgrown or unsightly, you may trim the roots as needed to maintain the look you want for your aquarium. Trimming of these roots will not harm the plant because their main function is not to absorb nutrients, but just to anchor itself to a surface.  

How do I identify and treat rhizome rot?

You can identify an unhealthy rhizome by its color and how it feels when you touch it. A dying section of rhizome will turn yellow, brown, or black, and will become soft and spongy. When you notice the rhizome rotting or dying, it is best to trim away the dying part of the rhizome in order to save the rest of the plant.

If the ends of the rhizome are rotting, simply cut off the unhealthy part with a pair aquascaping of scissors or a razor blade. If a middle section of the rhizome begins to rot, you’ll have to trim that rotting part off and you will have 2 healthy ends of the plant to reuse.

How do I propagate a rhizome plant?

To propagate or split the plant, simply cut the rhizome with sharp scissors or a razor to separate a few leaves from the original plant.

Stem Plants

Aquatic stem plants are a widely popular category used in the backgrounds or as the focal point of freshwater aquariums. Dutch style aquariums which feature an abundance of different stem plants and zero hardscape, have become increasingly popular in the hobby. Aquascapers love their attractive colors and bushy growth pattern, which make them an attractive attention grabber for any tank. Some examples of popular stem plants are Rotala H'ra, Ludwigia Natans Super Red, and Bacopa Monnieri. 

Should I trim my stem plants before planting?

When first planting new stems that have been propagated out of the water (emersed), it’s best to trim the emersed portions before planting in an aquarium. Emersed leaves will eventually melt once submerged since they are not suited for an underwater environment, so to avoid this whole process it is best to remove these portions prior to planting them in your aquarium. (Learn more about it in our article How to Prevent Plant Melt)

How do I trim and propagate stem plants?

Stem plants under ideal conditions can grow fairly fast, and when they reach the water surface, it's usually a good time to give them a trim. Stem plants exhibit an interesting characteristic, when cutting the stem between nodes (a section along the stem in which the leaves grow from), two new stems can sprout from the original stem.

The cutting you've just made can be replanted to continue growing, therefore with each trim you could potentially triple your stem count and density if you replant your cuttings. During planting, roots may be trimmed to make it easier to bury the stem into the substrate.

A good set of aquascaping pinsettes helps greatly when it comes to planting stems. We recommend using pinsettes with thin tips, such as the UNS Fine Tip Pinsettes, in order to plant each stem deep enough into the soil without issue. The thin tips of these planting pinsettes are beneficial because they help against damaging the delicate ends of the stems, the same thin tips also help with pulling the pinsettes out of the soil easily without pulling the plant back out with it.

Mosses

Mosses are the easiest plant species to propagate and trim. Good examples of mosses commonly used in aquascaping include the classic Java moss, Flame moss, and Christmas moss. Riccardia chamedryfolia is technically a liverwort, but is often referred to as a moss in the hobby and can be treated as such.

How do I trim and propagate moss?

Simply cut the moss to shape as you desire, even the tiniest fragments of moss can grow after it has been snipped. Having said that, when trimming your moss, make sure to turn your filter off and have a siphon handy to suck out any free floating bits right after you've trimmed it so that the moss doesn't float away and grow in any unwanted places in your aquarium. 

If you wish to replant and propagate your moss, simply take your trimmings and plant as normal. One of the most popular ways is to place the aquatic moss trimmings on the surface you wish to cover, and then use black thread to attach it. This method may be visible to begin with, but the aquatic moss will grow very quickly to cover.

Bulb Plants

Aquatic bulb plants have generally larger leaves that sprout from a thickened leaf base (the "bulb") that acts as a storage organ. The bulb part of the plant is arguably the most important, and we'll explain why below. Popular examples of bulb plants are Aponogeton Ulvaceus, Barclaya Longifolia, and Crinum Thaianum.

How do I trim and propagate aquatic bulb plants?

Plants which grow via bulbs, such as lilies and many Nymphaea species, can be propagated if you notice side-shoots coming from the bulb and sprouting new leaves in place near the original plant.

However, the bulbs cannot be split for propagation. Instead, these aquatic plant bulbs are better left alone and not divided or cut. The bulbs contain important organs vital to the survival of the plant and damaging such parts will lead to the death of the entire plant.

In regards to trimming, sometimes there are too many leaves or some older or unhealthy leaves start dying. When leaves start rotting of dying, simply cut off the old leaf with your curved scissors as close to the base of the leaf as possible. New leaves will not re-grow from where you trimmed, instead, they will emerge from the shoot tip of the tuber.

Rosette Plants

Rosette plants have a thick stocky section that resembles a rhizome. However, as opposed to the rhizome plants mentioned previously, the base of the plant should be planted in a nutrient-rich substrate, such as UNS Controsoil, and is typically smaller and more compact than a rhizome. The new leaves of rosette plants with appear in the middle, and branch out in a way similar to a rose's petals. Cryptocorynes, Blyxa, and Amazon Sword are common examples of rosette plants, and each are considered heavy root-feeders.

How do I prepare rosette plants for planting?

It's important to note that the base of these rosette plants is the most important part. In fact, you can trim off all of the leaves and cut back the roots, and it can completely develop into a healthy plant under proper conditions. Roots are commonly trimmed right before planting to make it easier to grab the rhizome and push it into the substrate.

How do I trim and propagate rosette plants?

Leaves should be trimmed if they have been damaged before planting, or if they start to rot in your tank. When trimming, use sharp scissors to cut as low on the stem as possible. This process will encourage new, healthy growth and leaves that are acclimated to your tank's conditions.

This is especially important with Cryptocorynes, which are notorious for melting in new environments. (Read more about crypt melt in our article, How to Prevent Cryptocoryne Melt)

• Note: Don't be scared to trim off yellowing or dying leaves of rosette plants. Remember that trimming these leaves allow will the plant to focus its energy and resources into the healthy leaves and new growth rather than waste it on the dying leaf.

To propagate, new side shoots will grow close to the mother plant, which can be cut and replanted elsewhere or in the same general area as the mother plant. 

Carpeting Plants

Carpeting plants grow to fill space and create an attractive foreground for any planted tank. Classic choices include Eleocharis, Marsilea, Monte Carlo, and Glossostigma just to name a few. These plants tend to grow horizontally rather than vertically (especially in high light with sufficient CO2 injection).

How often should I trim my carpet plants?

You should trim carpeting plants periodically. Not only will this encourage healthy horizontal growth, but it can prevent issues down the line. When carpet plants grow too dense and too tall, it can result in the lower portion of the plant to slowly rot and die because its not getting enough light.

Unfortunately, this can result in the plant detaching from the substrate and float to the surface. Although overgrowth can look great in some aquascapes, it can be short-lived if not properly and regularly pruned.

How do I trim and propagate carpeting plants?

Trimming your aquarium carpet is quite easy when using UNS wave scissors. Simply cut the plants horizontally while following the curvature of the substrate. The trimmings will float up to the surface where they can be skimmed or netted out for disposal (remember to dispose of your trimmings of all types responsibly!)

Alternatively, most cuttings of carpet plants may be used to propagate new plants if sprinkled onto some aquasoil and covered via dry start method. This works great with plants such as Monte Carlo or HC Cuba, however this method will not work with hairgrass trimmings because this plant grows via runners.

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