Selaginella lyallii

Care Guide: Planting, Soil & Watering

Overview: Selaginella lyallii (spikemoss) is a moisture-loving, shade-dwelling foliage plant that wants high humidity, rich organic soil and steadily moist — but never soggy — conditions. Unlike a succulent it must not be allowed to dry out, yet it still needs good drainage to keep its shallow roots from rotting.

Quick Care Requirements

Requirement	Ideal Condition
Planting Season	Spring to summer in zone 10b (avoiding the hottest days); spring to autumn in zone 11; year-round in zones 12+
Growth Rate	Moderate to Fast
Soil Type	Rich, moisture-retentive soil high in organic matter — a peat-based mix with perlite
Water Need	Moderate to High — keep the soil constantly moist and never let it dry out

Planting & Establishment

• Best Planting Season: Plant in spring once the weather is warm and settled, avoiding peak summer heat; it is frost-tender, so in cool climates grow it indoors or in a sheltered, shaded spot.
• How to Plant:
  • Hole Preparation: Prepare a hole only a little larger than the small, shallow root ball; spikemoss roots run near the surface and want a moist but well-aerated pocket rather than a deep one.
  • Soil Amendments: Work in plenty of compost, leaf mould or peat plus a little perlite so the soil holds moisture yet still drains — rich, spongy, humus-filled ground is ideal.
  • Planting Depth: Set it at the depth it grew before, leaving the creeping stems resting on the surface where they root as they spread.
• Growth Speed & Expectations: In warm, humid shade it grows at a moderate to fast pace, spreading into a soft, low carpet of foliage.

Soil, Watering & Drainage Care

• Soil Mix & Drainage Needs: Use a rich, organic, moisture-retentive mix (potting or peat soil with perlite); in pots choose one only 40–50% larger than the root ball with good drainage, so the soil stays evenly damp without turning stagnant.
• Watering Schedule & Technique:
  • Young / Newly Planted: Keep the soil evenly moist from the start and never let it dry; mist regularly to give young plants the high humidity they need to establish.
  • Established: Water regularly so the soil stays consistently damp — this is not a plant to let dry between waterings — and pair steady moisture with high humidity, especially indoors.
  • Seasonal Adjustments: Water a little less in cool winter weather when growth slows, but never let it dry out; increase misting and watering during hot, dry spells.

Growing in Pots, Balconies & Indoors

Selaginella lyallii is a low, moss-like spikemoss that the grower confirms grows well as a houseplant – as long as you keep the humidity up – and it grows well in containers too. Its love of shade and constant moisture makes it a natural terrarium and indoor plant.

Quick Details

• Container Size: A small pot 40-50% larger than the root ball for this tiny 5-15 cm plant (grower’s value)
• Indoor Suitability: A genuine houseplant – excellent indoors and in terrariums if humidity is high
• Best Spot: Full shade / bright indirect light – never direct sun
• Soil & Drainage: Rich, moisture-retentive but free-draining mix with organic matter
• Watering in Pots: Average to generous – keep evenly moist; never let it dry out for long

Indoors & On the Windowsill

• A humidity-loving houseplant: The grower confirms it grows well indoors provided you keep the humidity high. Give it bright, indirect light, steady moisture, and humid air – a terrarium, a covered dish or a pebble tray is ideal, as dry room air quickly browns it.
• Warmth: Keep it warm and away from dry heater or air-conditioner draughts, which dry it out fast.

On a Balcony or Patio

• Light & shelter: Outdoors it needs deep shade, shelter and constant humidity – only a protected, damp, shaded corner suits it; it dislikes sun, wind and drought.
• Practicalities: In open air it dries out very fast – it is far happier in an enclosed, humid setting than on an exposed balcony.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: Choose a pot 40-50% larger than the root ball (grower’s value), with strong drainage holes; keep the mix moist but not waterlogged.
• Potting mix: Rich, organic mix – potting or peat soil with perlite (grower’s spec), holding moisture while still draining.
• Feeding: Feed very lightly – the grower adds only a small amount of fertiliser every 3-4 years, plus humus and mulch.
• Repotting: Pot up when the roots fill the pot; once at its final size, every few years renew the soil and trim back some roots and foliage (grower’s method).

Grower’s Container Tip

• A little feed goes a long way: The grower feeds only sparingly – a small dose every 3-4 years with added humus and mulch – rather than regular feeding, which this delicate plant does not need.

Pruning, Training & Seasonal Maintenance

Selaginella lyallii is a compact, low mat-forming spikemoss, its green fronds sometimes edged in brown or yellow. It never flowers, and its naturally low, tight growth habit means it needs less shaping than larger, more sprawling Selaginella species – pruning is essentially grooming: removing dead or discolored fronds and containing the mat’s spread. It tolerates trimming year-round, with no bloom cycle to time around.

Quick Pruning & Maintenance Specs

Pruning Tolerance	Moderate (light grooming, minimal shaping)
Primary Pruning Window	Any time of year
Typical Frequency	Light, ongoing grooming as fronds brown or the mat spreads past its space
Main Objective	Remove dead/discolored fronds; keep the compact mat within bounds
Young Plant Priority	Let the mat fill in; no shaping needed yet
Mature Plant Priority	Trim spreading edges; thin dense patches for airflow
Best Tool Type	Precision snips

Pruning by Plant Age & Size

Newly Established

No trimming needed while the small plant (5–15cm) is filling in; remove only visibly damaged fronds from planting.

Young / Formative

No structural training applies to this naturally low, compact mat; it needs little if any pinching to stay dense, unlike more sprawling Selaginella species.

Mature / Established

Trim back the mat only where it has spread beyond its space, and thin occasional dense patches for airflow, since this species is noted to attract mealybugs, whitefly and spider mites in humid, poorly-ventilated conditions.

Special Growth to Remove

Fronds that have died or discolored at the edges (brown or yellow tipping is noted for this species and should be distinguished from normal leaf coloring before removing). Where the mat has spread beyond where it is wanted (this species is noted as invasive in favorable conditions), trim or lift out the unwanted sections.

Container & Small-Space Pruning

At repotting – typically every few years, or once roots fill the pot – growers are advised to switch the soil and cut back some of the roots and leaves together. Because this species is naturally compact, container specimens generally need less frequent shaping between repottings than larger, faster-spreading Selaginella species.

Tools

Precision snips are the only tool needed for this small, fine-fronded plant.

Tool Hygiene & Disease Risk

Routine risk – clean tools are sufficient. The pests noted (mealybugs, whitefly, spider mites) are not cut-transmissible, so blade disinfection is not a priority; improving airflow through occasional thinning helps more with pest prevention.

Cut Placement & Technique

Snip dead or discolored fronds close to their base without disturbing the surrounding healthy mat.

Post-Pruning Care

Maintain consistent humidity and soil moisture after trimming; no feeding is needed immediately after a light grooming.

Common Pruning Mistakes

Mistaking this species’ natural brown/yellow leaf-edge coloring for dieback and over-removing healthy fronds. Letting the mat spread untrimmed into neighboring plants instead of containing it early.

When NOT to Prune

Avoid heavy trimming right after repotting or root-pruning, while the plant is recovering from root disturbance.

Recommended Tools (by task)

Task	Plant Age/Size	Stem/Frond Size	Tool Category	Why
Remove dead fronds / contain spread	Any age, 5–15cm	Fine fronds and thin creeping stems	precision_snips	Delicate, controlled cuts suited to soft, small-scale foliage

Pests, Diseases & Troubleshooting

Overview: Spikemosses are moisture- and humidity-loving fern allies with delicate, scale-like foliage that is largely trouble-free when its cultural needs are met; most problems trace back to dry air, stagnant soil moisture, or the sap-sucking insects that colonise soft indoor foliage. Manage it culturally first — steady humidity, gentle airflow, and clean plants — and reach for treatments only when pests are confirmed.

Quick Troubleshooting Overview

Issue / Pest	Main Symptom	Primary Solution
Mealybugs	White cottony tufts in leaf junctions; sticky honeydew	Dab with alcohol; insecticidal soap or neem
Spider mites	Fine stippling, faint webbing, bronzed dry foliage	Raise humidity; rinse; insecticidal soap or oil
Whitefly	Tiny white flies rising when disturbed; sooty mould	Yellow sticky traps; insecticidal soap
Fungus gnats	Small black flies at the soil; larvae in wet mix	Let surface dry; sticky traps; Bti drench
Leaf browning / crisping	Fronds dry, brown at the edges or tips	Raise humidity, keep evenly moist, shade from sun
Root & crown rot	Blackened stems, collapse, sour wet soil	Improve drainage; ease off water; remove rotted parts

Common Pests & Management

• Mealybugs (Pseudococcus spp.):
  • Symptoms: White, cottony, waxy clusters tucked into the crown and where the tiny leaves meet the stems; they excrete sticky honeydew that can turn black with sooty mould. Slow-moving and easily missed on congested, mat-forming foliage.
  • Prevention & Control: Isolate the plant and wipe or spot-treat colonies with a cotton bud dipped in diluted rubbing alcohol. Follow with insecticidal soap or a light neem-oil solution, repeating every 7–10 days to catch newly hatched crawlers. Keep new plants quarantined and inspect the crown regularly, as dense growth hides infestations.
• Spider mites (Tetranychus urticae):
  • Symptoms: Fine pale stippling on the fronds, a dull bronzed cast, and in bad cases gossamer webbing over the tips — almost always a symptom of air that is too dry. Confirm by tapping foliage over white paper and watching for moving specks.
  • Prevention & Control: Prevention is humidity: mist, group plants, or use a pebble tray so the air never dries out. Rinse foliage to dislodge mites, then treat with insecticidal soap or a fine horticultural oil, covering the undersides and repeating twice at weekly intervals. Predatory mites work well in enclosed terrariums.
• Whitefly (Trialeurodes vaporariorum):
  • Symptoms: Clouds of tiny white flies lift off when the plant is disturbed; nymphs on the leaf undersides suck sap and produce honeydew and sooty mould, leaving foliage weak and dull.
  • Prevention & Control: Hang yellow sticky traps to monitor and thin the adults. Spray insecticidal soap or neem to the undersides in the evening, repeating every few days to break the cycle. Encourage airflow and avoid over-feeding, which produces the soft growth whitefly prefer.
• Fungus gnats (Bradysia spp.):
  • Symptoms: Small dark flies running over the soil surface and around the pot; their larvae live in the top layer of permanently wet mix and can nibble tender roots of young plants.
  • Prevention & Control: Let the surface dry slightly between waterings even though the plant likes moisture, cover the mix with a thin grit layer, and set yellow sticky traps. For persistent problems drench with Bacillus thuringiensis israelensis (Bti) or use beneficial nematodes.

Diseases & Fungal Issues

• Root & crown/stem rot (Pythium / Phytophthora / Rhizoctonia spp.):
  • Symptoms: Stems blacken and collapse at the base, foliage yellows and goes limp, and the mix smells sour — the classic result of soil kept saturated in poor light or cold, stagnant conditions.
  • Treatment & Management: Prevention is everything: use a free-draining, organic-rich mix, keep it evenly moist but never waterlogged, and ensure gentle air movement. Remove rotted sections back to healthy tissue, repot into fresh mix, and reduce watering while it recovers. Avoid cold water and cold, still rooms.
• Grey mould (Botrytis cinerea):
  • Symptoms: Fuzzy grey-brown mould on soft, congested foliage and dead frond tips, usually in cool, damp, still air with poor drying between waterings.
  • Treatment & Management: Increase airflow and reduce leaf wetness in cool spells, remove affected and dead material promptly, and thin overcrowded growth. Sanitation and drier air usually suffice; a copper-based or biological fungicide can be used if it spreads.

Growing Difficulties & Abiotic Problems

• Leaf browning & crisping (low humidity):
  • Cause & Symptoms: Fronds dry out, brown at the margins and tips, and the mat looks scorched — caused by dry indoor air, draughts, or letting the mix dry out. This is the single most common complaint with spikemoss.
  • Correction Strategy: Keep humidity high and consistent with a pebble tray, grouping, a humidifier, or a terrarium/enclosed case. Maintain even soil moisture, keep it out of hot draughts and heating vents, and mist with soft water in dry spells.
• Sun scorch & bleaching:
  • Cause & Symptoms: Direct sun bleaches the colour and burns patches brown; spikemosses are woodland-floor plants adapted to shade and dappled light.
  • Correction Strategy: Grow in bright indirect light or light shade, well back from hot windows. Introduce any new light levels gradually and shade from midday sun outdoors.
• Overwatering vs. drying out:
  • Cause & Symptoms: Both extremes cause browning: soggy stagnant soil rots the base, while any drying-out of this shallow-rooted plant crisps the foliage almost irreversibly.
  • Correction Strategy: Aim for constantly moist but well-aerated mix; water when the surface just begins to feel less wet, and never let the root ball dry completely. Good drainage plus steady humidity is the balance point.

What Helps — Products & Tools

For pest work on spikemoss, the gentle organic staples do the job: insecticidal soap and light horticultural or neem oil for mealybugs, mites and whitefly, rubbing alcohol on a cotton bud for spot-treating mealybugs, yellow sticky traps for whitefly and fungus gnats, and a Bti drench for gnat larvae. On the disease side a copper-based fungicide handles grey mould if sanitation alone falls short. The best ‘tools’, though, are a humidifier or pebble tray and a free-draining, organic-rich mix — keep the air moist and the roots aerated and this plant rarely needs sprays.

Propagation Guide

This spikemoss is propagated by rooting the base of its own leaves rather than by spores, which the site notes are difficult to use successfully, making vegetative propagation effectively necessary for reliable increase. It roots readily this way, making it an easy plant to propagate at home.

Quick Propagation Specs

Best Propagation Method	Leaf-base rooting (left attached until established)
Alternative Methods	Detached leaf-with-root cutting; spores
Propagation Difficulty	Easy (leaf rooting) / Difficult (spores)
Vegetative True-to-Type	Yes
Best Propagation Season	Spring to summer, avoiding the hottest summer days, per the site’s planting-season notes

Leaf & Root Cuttings

Roots naturally form at the base of the leaves. Two rooting approaches work: cut a leaf section that already carries a root and place it in water, changing the water every few days, or set the cut piece into rich, peat-based soil kept moist but well-drained, without letting it dry out. The site’s preferred, faster method is to leave the rooting leaf attached to the mother plant until the new roots have established themselves, only severing the connection once the piece is self-sufficient.

Spores

Spore propagation is possible but the site notes it is difficult, which is why leaf-base rooting is the recommended and effectively necessary method for this species rather than an optional alternative.