Hygrophila Siamensis

Usual aquarium appearance

This medium to tall plant has broad lance-shaped leaves. Its commonly observed colour is green to bronze. Colour, leaf size, and internode length can change with light, CO₂, nutrients, temperature, and the individual plant.

It grows from upright or trailing stems and normally branches after trimming.

It is normally used for fast midground and background groups. During the first few weeks, watch the growing tip, roots, and new submerged leaves. Do not judge success only from old nursery-grown foliage.

Essentials

• Start with low to medium light.
• Provide a planted substrate or inert substrate with suitable root nutrition.
• Use a complete fertiliser routine that supplies both macronutrients and micronutrients when the aquarium does not provide enough through feeding and livestock waste.
• Provide gentle to moderate circulation without repeatedly bending or uprooting delicate stems.
• Keep temperature and basic water conditions stable. Observe the plant instead of chasing one exact number.

Optional improvements

• Stable injected CO₂ can improve branching, colour, density, and recovery where recommended.
• A mature aquarium is easier because early algae and parameter swings are less severe.
• Regular topping and replanting can keep stem groups dense and prevent bare lower sections.

Beginner setup checklist

• Filtered, cycled freshwater aquarium
• Stable light schedule
• Suitable substrate or floating position
• Consistent fertilising
• Gentle circulation around the foliage
• Clean scissors and tweezers
• Space for the plant’s expected spread or height

CO₂ guidance

Injected CO₂ is optional. It can improve establishment, branching, and recovery, but the plant can usually grow without it when light and nutrients are modest and stable.

CO₂ must remain stable and be balanced with light, macro- and micronutrients, circulation, and oxygen. Adding CO₂ does not make very strong light automatically safe.

Increase light or fertiliser only after the plant is producing healthy new growth. Sudden changes can cause melting, algae, or stalled tops.

Preparation

• Remove pots, metal bands, foam, and rock wool.
• Rinse the stems and remove crushed, fully decayed, or badly damaged lower leaves.
• For tissue culture, rinse away all gel and separate the cup into small natural portions.

Planting stems

• Separate the bunch into individual stems or small groups.
• Use tweezers to insert only the bare lower stem and any roots into the substrate.
• Do not bury healthy leaves or pack stems tightly together.
• Leave enough spacing for water movement and light to reach the lower growth.

Attachment does not normally apply

This plant should be rooted in substrate, floated, or allowed to spread through runners according to its growth habit. Do not glue healthy stems, crowns, or roots to wood or stone.

Trimming stems

• Use clean, sharp aquascaping scissors.
• Cut above a healthy node when the group reaches the desired height.
• Replant healthy tops after removing leaves from the section that will be buried.
• Leave rooted bottoms to produce side shoots, or replace old bare bases with the fresh tops.
• Avoid removing most of the plant mass during one trim when the plant is weak or newly established.

Frequent light trimming usually creates denser growth. Long delays between trims can produce shaded, bare lower stems.

Propagation by stem cuttings

• Cut a healthy top section below a node.
• Remove leaves from the lower part that will enter the substrate.
• Plant the cutting with spacing around it.
• Keep the rooted base if side shoots are wanted, or remove it when it has become old and bare.

Propagate only healthy growth. A melting, algae-covered, or recently imported plant should recover before being divided or cut heavily.

Normal adjustment

Transport, planting, and conversion from emersed to submerged growth can cause temporary leaf loss or slow growth.

• Normal signs include firm growing tips, new roots, side shoots, and gradual production of new underwater leaves.
• Emersed-grown leaves may melt while narrower or differently coloured submerged leaves develop.
• Colour can change as the plant adapts to the aquarium.

Signs that need attention

• Softening stems or crowns, transparent new growth, repeated loss of every growing tip, or spreading decay.
• Severe twisting, stunting, or algae appearing mainly after a change in CO₂, light, or fertilising.
• Roots repeatedly lifting from the substrate because the plant was planted too shallowly or the flow is too strong.

Nomaphila siamensis is a synonym of Hygrophila corymbosa. This trade form grows quickly and can become large.