Monstera deliciosa care guide

The maximum near 250 µmol/m²/s was measured on single leaves after at least 3 days under a blue-red lamp at 500 µmol/m²/s and 21 °C.⁴ Another measurement on M. deliciosa reported net photosynthesis above this saturated rate at lower light, and the two results stand unreconciled.⁴

In pothos grown at the same photon flux of about 90 µmol/m²/s, the light source it grew under shifted the fitted saturation point: about 91 µmol/m²/s under fluorescent tubes against 132 and 236 under two red-blue LEDs; that the growth light shifts the fitted saturation point carries over to Monstera, which way and by how much does not.⁷

Above about 300 µmol/m²/s under a steady lamp a green leaf is not expected to gain further photosynthetic capacity, and plants under glasshouse midday peaks of 1500 µmol/m²/s ended with no higher photosynthetic capacity than plants under peaks of 300.¹

These light sentences rest on glasshouse and growth-chamber measurements on green M. deliciosa.¹ In a naturally lit glasshouse, plants grown under midday peaks of 1500 µmol/m²/s did not differ in photosynthetic capacity from plants grown under peaks of 300, and their leaves showed no lasting photoinhibition.¹ Leaves developing under the 1500 peaks built much more fast photoprotection than under 300, while shade-grown leaves moved straight to 700 µmol/m²/s in a growth chamber were badly photoinhibited after 5 days and raised no such protection.¹ Shade leaves lost 21 % of their photosystem efficiency after 1.3 hours at 600 µmol/m²/s, and more at higher light.²

Under a constant 12–14-hour lamp day, a green leaf needs about 0.5–0.6 mol/m²/day for net carbon gain in the lamp hours and saturates at about 10.7–12.4 mol/m²/day.⁴ A green leaf acclimated to bright lamp light starts net carbon gain at about 12 µmol/m²/s.⁴ After acclimation at about 20 µmol/m²/s with 8-hour days, a value of about 3 is given for M. deliciosa, second-hand and under the name Philodendron pertusum, and a second fit of the same data by the same group gives a much higher value.⁸

Green M. deliciosa can be grown indoors at 10 µmol/m²/s, but leaves grown there had significantly lower photosynthetic capacity than leaves grown under glasshouse peaks of 300 or 1500 µmol/m²/s.¹ After three months at 10 µmol/m²/s, a potted plant in a closed chamber released more CO₂ than it fixed over the light-dark cycle, while at 40 µmol/m²/s it ended with net uptake.⁹ Shade-grown plants moved straight from 10 to 700 µmol/m²/s were badly light-damaged after 5 days and gained no photosynthetic capacity.¹

In shade it is described as forming long, narrow internodes (the stretches of stem between two leaves) and staying smaller, and young plants in low light as keeping thin internodes instead of thickening.¹⁰ Young plants under LED light with 12 % far-red were not taller than under 1 % far-red, in a winter greenhouse with daylight plus at most 100 µmol/m²/s of LED light and one greenhouse half per spectrum.¹¹ In its native forest it is described as growing across the full range of natural light, from the deep shade of the forest floor to the sunlit canopy.¹

A lux meter’s own error is about 10–20 %, and light across a lit area can vary by up to 30 %.⁵ A conversion factor of about 53.8 lux per µmol/m²/s, used for daylight and white LED alike, overstates the photon flux of white LEDs by 19–38 %.^12,5,13

The support result comes from a related Monstera and from pothos, carried over to M. deliciosa.^1,2 On the support, the last leaf of the related Monstera obliqua reached about six times the first leaf’s area, against about twice on hanging shoots; these multipliers belong to that species.¹ In pothos under high light, contact tripled leaf size, while a shoot led straight up without touching a support made leaves no larger than one lying flat.² In pothos under low light, the support made no difference to leaf size.² In Monstera obliqua, even hanging shoots doubled their leaf size, a difference between the species.^2,1

In climbing aroids including Monstera, a shoot that gains a support makes short internodes with well-developed leaves and a stem that thickens until the species’ full size is reached.⁵ In Monstera and its relatives, side shoots arising from the axils of perforated leaves are described as soon making leaves with more holes and deeper cuts when they cling and grow upward, and not when they hang as whips.⁶

In the largest Monstera species, plants reach flowering size only on the largest forest trees: how large a plant can become depends on the size of its host.³ In the wild, a large Monstera on a tree too small for it grows away from the trunk at the first branches, and its hanging tip grows back down to the ground.³ In Monstera, adult stems that come loose and hang can turn juvenile again, with long internodes and reduced leaves, while M. deliciosa’s own section of the genus is named as a possible exception.⁷ In two wild Monstera species, large plants stay connected to the soil through their roots after the base of the old stem has died back.⁸

The two root kinds are described on wild climbing Monstera.^3,4 In one wild example, a stem growing past the top of a stump formed fewer roots on the following internodes, and these stopped growing at about 1 cm.³ On wild M. deliciosa the clinging roots are grey and 5–8 mm thick.^3,4 Free-hanging aerial roots of M. deliciosa in a summer greenhouse grew on average 9.6 mm a day.⁹ The part of an aerial root that hangs in the air loses water more slowly than the part of the same root that has grown into the soil.¹⁰ On one outdoor M. deliciosa whose hanging feeding roots were cut back regularly, the cut roots branched, while uncut feeding roots of the species normally stay unbranched in the air.^4,3

In two wild climbing aroids, Philodendron radiatum and Anthurium clavigerum, soil-rooted feeding roots cut about 1.5 m above the ground dried at the cut end, and new tips grew on 87.7 % and 50.5 % of the cut roots against 7.7 % and 36.9 % of uncut aerial roots; in A. clavigerum cut and uncut roots did not differ statistically.¹¹ In excised 5-cm pieces of host-attached feeding roots of two related climbing aroids, Rhodospatha and pothos, a tracer applied only to the bark-facing side reached the root’s core within two hours; the air-facing side was not offered the tracer, and no pole or moss was involved.^12,10

The night-temperature series was measured on pothos, a close relative, and its direction holds for Monstera.³ In pothos, vines grew 115, 165 and 179 cm in eleven weeks at minimum nights of 15, 18 and 21 °C; for Monstera only the direction carries over, not the size of the gain.³ Young M. deliciosa made 1.5 to 2 times the above-ground weight over a winter at a 21 °C daily mean as over one at 18.4 °C, but that warmer winter also brought larger starting plants, another substrate, stronger feed and longer lamp days.⁴

A temperature of 12 °C or more is named as its suitable temperature, without saying whether that is a limit for growth or for survival.^1,2 M. deliciosa is described as unable to tolerate frost, in accounts that give no plant temperature, while outdoors in central Florida it grows vigorously, flowers and sets fruit although it is exposed to frost every year.^1,2,5

In pothos held at 1 °C for 28 days, chlorophyll and membrane integrity were lost first, by day 7, water content and photosystem function (Fv/Fm) followed from day 14 and severe cell deformation from day 21; for Monstera the sequence carries over in direction, not in timing.⁶

Potted pothos ‘Marble Queen’ in dark cold storage stayed unmarked after 4 days at 7.8 °C.⁷ Scindapsus pictus ‘Argyraeus’ at 4.5 °C in the dark showed water-soaked, black-grey leaves after 2 days, and every plant chilled for 4 days or longer died within 8 weeks.⁸ Heart-leaf philodendron kept full grade after 1 day at 2.2 °C, 2 days at 5 °C or 4 days at 7.8 °C in the dark, and longer spells at 2.2 °C lowered it.⁷ Philodendron domesticum stepped down weekly to 0 °C still looked intact, but wilted with lasting cold injury once back at 25 °C.⁹ In chilled foliage plants, among them Scindapsus and Dieffenbachia, damage appeared with delays ranging from the time of chilling to about day 11–13.^10,7,8

For foliage plants in general, growth is said to slow to little or nothing once the root medium is below about 15.5 °C while nights stay at or below about 18.3 °C, yet a heart-leaf Philodendron held at that boundary grew nearly normally.¹¹ In Spathiphyllum seedlings, a non-climbing aroid, a 32/22 °C day/night regime gave the poorest plants, against 22/16 and 27/19 °C.¹²

The watering rule is a conclusion from four links: overwatering is the more frequent cause of rot in M. deliciosa, the base of a drained pot is its wettest part, air returns to the mix as it dries, and in pothos water use rose with light, so need changes with the spot.^1,2,3 That overwatering is the more frequent cause of rot comes from one houseplant account, without counts.¹ One houseplant account describes rot of M. deliciosa as wilting leaves and stems, a stem girdled by rot at soil level, and brown to black, mushy roots that pull away easily.¹ Wilting alone has several causes in house plants generally: too little water, too much light, or root rot from overwatering, and white roots are healthy while brownish-black roots point to rot.^6,1

In a just-drained 4.5-cm peat cell, the air sat near the top: about 20 % of the volume at 0.5 cm depth was air, and about 1 % from 3 cm down.⁷ The same cell, dried from 72 % to 51 % water by volume, held 24–29 % air at every depth.⁷

In one winter, young plants in a peat-free mix dried faster than in a peat mix and needed extra hand watering about 3 to 4 times while both shared one watering section; with another peat-free mix the next winter they needed none.⁸ In potted pothos at 30 µmol/m²/s, the middle of three watering regimes gave the largest leaf area, and the driest and the wettest both gave less.⁹ In self-watering containers indoors, golden pothos used more water at higher light across 50–200 foot-candles.¹⁰

For the same weekly salt input, pots of four foliage plants, Dieffenbachia among them, given 2 litres a week in a bright greenhouse ended with a far less salty mix than pots given 1 litre in a dim interior room, because less water passed through; light there changed together with temperature and humidity, and the watering volume followed the plants’ demand.¹¹ The direction holds for Monstera where watering follows demand, while in Impatiens watered by a fixed amount across light the difference did not appear.¹¹

In small peat–perlite pots of 370 and 615 mL watered from below with no water draining through, feed salts gathered in the top layer: after 77 days the top layer’s EC was 2 to 5 times that of the layers below.¹² A pot watered from below does not wet evenly: coarse particles and tall pots slow the rise of water, and in one peat–perlite pot the top layer stayed dry up to 20 hours after watering.^13,14

The misting sentence comes from pothos.⁴ Pothos leaves sprayed with dew-sized amounts of water took in only 2.45–6.15 % of it, and the film was gone in under an hour at about 23 °C and 80 % relative humidity.⁴ M. deliciosa leaves carry most of their pores (stomata) on the underside between the veins and the next most along the upper midrib, while the upper blade between the veins has almost none.¹⁵ On wound-inoculated Araceae, taxa not named per case, spots of the bacterium Pseudomonas cichorii stayed small when the leaves were kept dry after the first symptoms, but on susceptible taxa covered much of the leaf under intermittent misting.¹⁶

The mix sentence is a chain about waterlogging, none of its links measured in a potted aroid: a coarser grade drains to more air, a saturated root zone is short of oxygen, and root-rot organisms do best there.^1,6,7 In tomato pots flooded 1 cm above the soil for five days, drip water enriched to 10–20 mg/L dissolved oxygen partly reversed the leaf and root losses against water at 5 mg/L.³ Finer grades of the same material held less air after draining: air-filled porosity fell from 38.7 to 13.5 % in pumice and from 45.02 to 7.97 % in pine bark.^6,7,8 In a drained pot the base is wettest, and in a just-drained peat cell almost no air remained from 3 cm down.^9,6,10 In M. deliciosa as a houseplant, overwatering is named as the more frequent cause of root and stem rot than drought, in one account without counts.⁵ In hydroponic tomato, the root-rot organism Pythium colonised roots more at low dissolved oxygen than at 11–14 %.² In container cherry seedlings (Prunus), a 4–5-day flood cut survival from 99 % to 84 %.¹² Caladium roots kept saturated from a saucer of standing water rotted within 3 days of Pythium inoculation, under conditions chosen to favour the pathogen and with no arm that was not saturated.¹ The chain covers waterlogging, not every watering level: with a root pathogen present in tomato and chrysanthemum, the drier of two sensor-held watering levels worsened its harm in two of three mixes per crop, and no mix showed a significant worsening on the wet side.¹³

M. deliciosa cuttings, watered three times a week and fed weekly, grew about the same in stem length and largest new leaf over 58 days across eight 1:1:1 potting mixes, three of them without peat (n and test not stated).⁴ The cuttings were misted for their first month, and soluble salts across the eight mixes ranged from 196 to 3,262 ppm without a difference in growth.⁴ That trial measured growth, not how a mix forgives a watering mistake.⁴ Across many pot-mix trials on ornamental pot plants, the aroids Spathiphyllum and Aglaonema among them, the mix changed growth in most designs, yet in none could the effect be pinned on one property.^14,15,16 Young M. deliciosa grew for 18 weeks in a peat-free mix without visible harm to shoots or roots, at a pot pH of 4.8–4.9 against 5.9–6.4 in the peat mix.¹⁷

More pot volume gave more plant across 65 pot experiments on many species, and that direction carries over to Monstera, while none of these experiments looked at watering, rot or waterlogging.^11,18 For M. deliciosa itself, one houseplant account describes a tight pot as tolerated far better than an oversized one and gives roots reaching the bottom and sides of the pot as the cue for repotting, one size up at a time; another view on climbing aroids advises thinking ahead to the final size, since a large climber is hard to repot.⁵ That tight-pot advice sits under root and stem rot, and no reason is given for it; growth and rot risk are two different questions, and the two statements are not opposed.⁵

In cores of fine peat–perlite without plants, the taller core of 15.2 cm held 0.311 cm³/cm³ air after draining against 0.203 in the 7.6-cm core, by the per-mix statement, while the main effect of height on air space was not significant; the container capacity of coarse bark did not change.^9,6,10 That the base of a drained pot is its wettest part is a cited mechanism of about 1 hPa per cm of height.^9,6,10 Grain size and pot height interact: the finest pumice gained air as the container got taller, a calculated 6.3 % in an 8-cm bag against 12.7 % in a 24-cm pot, while the coarsest grade drained to near its residual water.⁶

Finer is not simply wetter: in pumice, easily available water was highest in the 0–5 mm grade and lowest in the 4–8 mm grade.⁶ A mix’s total pore space does not describe its air: in two series total porosity stayed flat while air moved, and in a third total porosity rose while air stayed the same.^19,20,21 A recipe of named components does not fix the mix’s physics: one compost gave 13.7 to 25.9 % air depending on the supplier.^22,23,24

A mix changes over time: in unplanted pots fed for 14 weeks, air space fell in peat-lite and in fine pine bark, and not significantly in coarse pine bark.²⁵ In a seven-month pot crop, the share of particles above 1 mm fell by 38.0 % in pure peat but by 7.6 % in pure green-waste compost.²⁶ A vigorous root system lowers a mix’s total porosity within weeks.^27,28 In a bark-based mix, coir changed least in air and water-holding over eight months, while sedge peat, the airiest at the start, largely reversed; a coir mix under Dieffenbachia, though, fell to 3.6 % air within five months.^29,30

In three foliage mixes, coir dust in place of peat held more water, and Dieffenbachia grown in it had higher top grade and top mass, while growth index and roots did not differ; the water effect was not separated from the coir mixes’ higher starting potassium and salt, and the direction carries over to aroids in pots.³⁰ In tissue-cultured Syngonium liners grown for four months, replacing a fifth of the peat with biochar or biochar plus compost raised air space from 9.06 to 13.76–16.36 % and gave larger plants, but salts, pH and leaf nutrients rose with it.³¹ In a 2 sawdust : 1 peat mix under tomato with about 20–30 % air, gas oxygen at mid-height stayed above 17 % on four dates, also under constant wetting from below, yet aeration limits were still reported for that crop.^32,33

Vines with established aerial roots are described as rooting well with little rot when buried to within 2–3 inches of the first leaf node, while buried growing tips are more likely to rot.⁵ Moved from potting mix into clay pebbles, pothos with all roots removed ended with 43–59 % less root mass than unpruned plants, and all survived; the direction carries over to Monstera.³⁴

The mineral-against-compost result comes from sandy beds under 63 % shade netting, and its direction holds for a pot.¹ In sandy beds under 63 % shade netting, M. deliciosa given ammonium sulphate as its only nitrogen made leaves of 745 cm² (length × width) against 432 unfed and 485 with compost only, and leaf size fell as the compost share rose.¹

At dim interior light of 100 foot-candles, two other aroids, Aglaonema and Dieffenbachia, kept grade and height unchanged at 0, 1 or 2 g of 19-6-12 per 6-inch pot over six months, and that direction, no gain from feed in dim light, holds for Monstera.³ Pothos in an indoor hydroponic unit at about 1 µmol/m²/s room light grew no better fed than unfed, while from 20 µmol/m²/s of added 12-hour lamp light, fed plants outgrew unfed plants at twice the light.²

Pothos, a Philodendron hybrid and Syngonium showed no significant growth difference (data not shown) between captured water with an alkalinity of 95.0 mg per litre and well water with 111.8 mg per litre; the two alkalinities lie close together, and for water of this alkalinity the same is expected for Monstera.⁵ In hibiscus, with sodium changing alongside, bicarbonate water raised the mix pH and paled new leaves while the conductivity (EC) of the mix stayed flat; both directions carry over to Monstera.⁶ In salvia on limed peat–perlite watered with deionised water, the share of nitrogen given as ammonium moved the mix pH more than any other feed factor tested, from 6.01 to 4.95 between 0 and 5.6 mM ammonium, and the direction carries over to Monstera.⁷

Leaves of good-quality M. deliciosa grown in Florida held 2.5–3.5 % N, 0.20–0.35 % P, 3.0–4.5 % K, 0.4–1.0 % Ca and 0.3–0.6 % Mg in dry weight; these describe healthy plants, not deficiency limits.⁸ In Florida foliage production, M. deliciosa is placed in fertilizer category 4 of 5, for a 20-cm pot 8.6 g of a 19-6-12 controlled-release fertilizer every 3 months, a production rate.⁹ For pothos and philodendron in the brightest band of an interior feed table, about a third of that nitrogen is listed.^10,9

In a Florida foliage greenhouse, captured water (pH 9.7 in the collection basin, 8.8 in the pipes) and well water at pH 7.6 left a peat-based mix at a mean pH of 6.6 and 6.3.⁵

All holes of one Monstera blade, large and small, start together as tiny sites 7–20 cells across, and growth then enlarges each about 10,000-fold in area.⁵ In a Monstera leaf, most perforation happens before the leaf is visible, and a hole opening later in a mature leaf is rare, the tissue between two veins thinning over about a month.⁶ A marginal split can begin as a hole between two side veins that widens toward the edge and finally tears through it.⁷

Adult wild M. deliciosa carries 10–101 holes per side of the blade, of very unequal sizes, with 6–12 lobes per side.⁸ Wild adult blades are mostly 40–75 cm long and 40–55 cm wide, juvenile-phase blades 15–23 cm long.^9,10

The sun and shade leaves grew at one site, without a light reading.³ At sun and shade sites on one campus, mature leaves had close total leaf areas while their hole area differed strongly, and shade leaves carried more leaf area per gram.³ Across leaf-size trials on pothos, Syngonium and other aroids, more light gave slightly smaller single leaves in the brighter range, while in very deep shade more light gave larger leaves.^11,12

One stem kept outdoors in summer and indoors in winter made smaller, more oval leaves with entire edges in winter and split its leaves again the next summer; season, light, warmth and the move indoors changed together.⁷ That stem made about one leaf a month in its first summer and one every two months otherwise.⁷ One rooted cutting made two entire leaves first and its first marginal split at leaf 4, about four months after its first leaf; on a separate plant, one new side branch carried split leaves again from its second or third leaf.⁷ One main stem cut back to about 10 cm above the ground regrew with a split first leaf and strongly split leaves after it.⁷

One thidiazuron drench on a related Monstera that does not branch from its base made basal buds elongate but gave no shoots within 12 weeks and cost roots from 5 ppm on, and the same is expected here.¹³

In a conservatory, one plant climbed about 12 m.¹⁴ Growth speed differs widely between Monstera species: in the wild, M. obliqua added 2–5 m of stem and 30–70 leaves a year, adult M. lechleriana 12–20 cm and 4–8 leaves.¹⁵

Thicker stem pieces survived better, 45.00, 53.33 and 73.33 % from thin to thick, with only the thickest class standing apart, and thickness changed neither the time to break dormancy nor the share that sprouted.² In soil with manure and rice husk, air-dried stem pieces survived, sprouted and rooted better than in soil with manure and sand.² In tissue culture, node pieces gave 2.4–3.1 shoots per cycle from the bud at each node, while adventitious routes gave 13.9 per responding leaf-stalk piece and up to 25 per callus piece.^5,6,7 Carrying callus forward under a high cytokinin dose is the route treated as prone to off-types.^3,4

Vitamin B1 at 1–4 cc per litre of water did not make tip cuttings grow taller or leafier over 84 days.⁸ Air layering, rooting a stem while it is still attached to the plant, is a route named for M. deliciosa among large foliage plants.⁹ Not every Monstera roots easily from stem pieces: twelve stem divisions of M. tenuis gave no rooted plant, in a collection where the other Monstera species propagated with little difficulty.¹⁰

In pothos, node cuttings that kept a 6–8 mm stub of old aerial root reached more fresh mass by day 55 than cuttings with the root removed.¹¹ Pothos cuttings that already carried roots kept growing for 56 days in plain tap water.¹² Cuttings of Ficus benjamina, a non-aroid, formed no roots in water without dissolved oxygen in 38 days, but 83–100 % rooted at 2.5–8.0 mg/L.¹³ In a cool winter root zone, a rooting medium held at about 24 °C raised the rooting grade of pothos and heart-leaf philodendron cuttings.¹⁴ Pothos cuttings started the same number of roots in all 13 mixes tested, and the mix acted on root length; the direction holds for Monstera in its green and yellow-variegated forms, while white-variegated forms are left out of that transfer.¹⁵

A tissue-culture route for M. deliciosa from single-bud stem pieces, without a reported callus step, gave about 3 shoots per piece, rooted almost completely, and 94 % of the plantlets with at least two roots took to pots.⁵ From seedling shoot tips, M. deliciosa gave 8 shoots per culture in 6 weeks, more at 30 °C than at 21 or 24 °C, and the plants matched the original clones in form.¹⁶ In aroid tissue culture, sterilisation is the stage that decides: controls without the full treatment regularly failed, while after 0.5 % sodium hypochlorite 80 % of M. deliciosa node pieces were viable.^6,17,5 Several lab protocols step aroid plantlets down from near-saturated air over two to four weeks, at humidities from 45–55 % to 95–100 %, and misted Philodendron billietiae survived with or without a cover.^6,18,19

Monstera tissue culture sold as ‘Grade B’ meant three different things at three shops: smaller and less variegated, variegation promised after 4–6 leaves, or nothing checked.^20,21,22 Where ‘Elite’ is a certification class, as in a Dutch scheme that covers Anthurium, it marks a health and identity pedigree, not plant size.²³

The paler new leaves are a known pattern in greenhouse-grown M. deliciosa, and growers say the colour often greens again later.³ Growers link the paler new leaves to strong growth and suspect iron shortage, and iron in the feed was raised during that crop.³

In one shade-house plantation for cut foliage, a new leaf reached its full size about 7 days after it had fully unfolded, while its greenness kept rising for about 60 days.⁴

On tree philodendron, a wound let even a small dose of a soft-rot bacterium cause blight, and longer leaf wetness added to it; the direction holds for Monstera.¹ The bacterium Pseudomonas cichorii infected M. deliciosa leaves after needle wounds and a moist chamber, then misting.^2,3

Indoors, M. deliciosa is described, in one crop account without references, as subject to scale insects, mites and mealybugs.⁴ Against aroid leaf rust, an agency’s recommendation for Florida nurseries gives isolating newly bought aroids for 40 days and destroying infected leaves, leaf litter and heavily infested plants.⁵

Aroid leaf rust is a confirmed pathogen of M. deliciosa: all plants inoculated with its spores showed symptoms by three weeks, uninoculated plants none.⁶ Under low humidity, rust lesions on M. deliciosa can stay smooth without visible spores, so missing rust-coloured powder does not rule out rust.⁵ As a house plant, M. deliciosa is also described with anthracnose as yellowing along the leaf edges that turns tan, then dark brown, and spreads inward.¹¹

On coleus, one spray of potassium bicarbonate at 5.9–14.9 g/L killed most young citrus mealybugs within 7 days, while 14.9 g/L burned the coleus leaves; the effect on young citrus mealybugs carries over to Monstera, one contact spray on the same pest species, while no aroid leaf was sprayed.¹⁴ Excess boron marks mature leaves first, as yellowing with brown spots that starts at the tip and spreads toward the base, as seen in pothos and heart-leaf philodendron; the position carries over to Monstera.¹⁵

‘Thai Constellation’ leaves saturated at about 434 µmol/m²/s against 247 for green leaves, with the same compensation point of 12 µmol/m²/s, measured on single leaves after at least 3 days at 500 µmol/m²/s under a blue-red lamp.¹ For variegated forms other than ‘Thai Constellation’, the green form’s saturation of about 250 µmol/m²/s holds only within a wide band of about 100–600 µmol/m²/s, with no direction up or down.^1,6,7

For variegated M. deliciosa leaves at least about 30 % green, the compensation point is expected within a wide band around the green form’s, under the same light history, and in whiter leaves higher; the 30 % limit comes from a dilution model with white tissue respiring at about half the rate of green tissue.^1,6 In six variegated-versus-green pairs of pothos, ivy and other plants, the variegated form came off worse at the lowest light.^8,9

The white-leaf sentence links these findings.^2,3,4 The white margin of a white-margined pelargonium holds almost no soluble sugar and is read as a carbon sink depending on the green sector beside it; this reading carries over to aroids.¹⁰ In the pelargonium margin, glucose stood at 0.08 against 7.73 mmol/g fresh weight in green tissue, values taken from earlier work, and no sugar transport was traced.¹⁰ In a tomato (Solanum lycopersicum) variegation mutant, white leaf sectors respired rather than photosynthesised at 400 µmol/m²/s.¹¹ Chlorophyll-free tissue failed once it had to stand alone: a chimeral petunia’s white sector grew and flowered while attached, but its cutting died, and all-white ‘Albo’ leaves and cuttings are described as browning or dying.^12,13,14 In Anthurium tissue-culture lines moved unfed into moss, 7 of 9 lines with more than 50 % non-green leaf area died and none of 11 at or below 48.7 %, while one line survived at 84.1 %; these shares describe whole plantlets, not single leaves.¹⁵

Every variegated side shoot counted in a variegated Anthurium in tissue culture grew from the axil of a leaf that was variegated itself, and for sectored variegation in Monstera the same one-way rule holds.¹⁶

In one ‘HUTAMT41’ plant, the pale flecks came out white on leaves that grew in a shaded greenhouse at up to about 30 °C and yellow-green on leaves that grew outdoors in brighter light at about 35 °C or more, light and warmth changing together.¹⁷ In two chimeras of ivy and Dracaena, light shifted the white share in opposite directions: ivy ‘Gold Heart’ showed more variegated area in more light, Dracaena ‘Ribbon’ more white in deeper shade.^18,19,20

In one variegated Syngonium, most plastid DNA in white tissue carried a gene defect, against a minority in green tissue, and cells holding both kinds of plastid are described as turning all-white as the plastids sort out at random; the mechanism carries over to Monstera as a model, while no Monstera form has been sequenced.²⁷ In the sectioned ‘Variegata’, single cells of finely striped young leaf areas held both green and white plastids, which points to such sorting-out as the basis of the pattern in that plant.⁵ In one golden pothos plant, pale sectors differed from green ones in how strongly a nuclear chlorophyll gene (EaZIP) was expressed, not in the plastid genome; this is read as a nuclear mosaic and serves as a model for sprinkle cultivars of Monstera, without placing any cultivar in that group.^29,27 Where variegation sits in whole cell layers, a cutting from a node carries it on with a small rate of off-pattern shoots that depends on the arrangement: of six such tobacco chimeras, four showed no off-pattern leaf on 24 plants each and the other two on 3 and 4 of 24, a class rule transferred from tobacco.³⁵ In a layered pelargonium chimera, stem cuttings kept the parental form in 15 of 15 plants and callus shoots in 1 of 166.³⁶

In the sectioned ‘Variegata’, no white-margined or white-cored plant appeared among 9, and since its outer layer forms only the leaf skin, green beside white in one leaf can be read as sectors or mixed cells of the inner layer.⁵ In three-layered chimeras of ornamental dicots, where the outer layer mostly forms only the leaf skin, a mutation in the second layer gives a conspicuous white leaf margin.¹³ A chimera cannot be read from the leaf: an African violet pattern thought layered proved purely genetic, and sharp borders, vein-bound green flecks and seasonal change each occurred in both chimeras and non-chimeras of Ficus, Hosta and other plants.^37,38,39

Of 9 cuttings of the sectioned ‘Variegata’, taken at finely mixed leaf areas in one propagation round and followed over about 19 internodes each, 8 still carried a mixed or sectored pattern, one turned all white and none all green.⁵ In a mixed-cell variegated Syngonium, all-green shoots that had sorted out stayed green when propagated, all 54 plants from 6 such shoots.⁵ In variegated mint, 74 of 87 branches stayed mixed, 12 turned all white and 1 all green, and across six such cultivars of Spiraea, mint and Euonymus, sectored branches whose fate had resolved ended in the mutant form 232 times and in the original form 37 times.^40,39,41 In a variegated pelargonium hybrid, one of four clones kept vegetatively for over 20 years had sorted out to dark green.²⁸

Seed did not pass on a layered chimera’s pattern: a variegated pelargonium chimera as seed parent gave 63 green, no white and no variegated seedlings.^13,42 Where variegation is a plastid mixture passed on through the mother, seed can carry it: in onion (Allium), 40 of 374 seedlings from selfed variegated mothers were striped.⁴³ In Caladium, a nuclear gene for a uniform leaf background colour splits in seed by simple ratios, lemon against green 248 : 76 on selfing.^30,31

In an Anthurium line whose variegation arose in callus, axillary buds kept no more variegated plants than callus did, 15 of 39 against 36 of 79.⁴⁴ Through fast callus or leaf-stalk routes, shoots of layered chimeras stayed true in 0–65 %, and two Caladium cultivars read as non-chimeral in 97.9–100 %, while in nine other Caladium cultivars read as non-chimeral, four threw off-types.^32,33,34 In strawberry ‘Albo-Marginata’, a layered chimera, 86.9–95.5 % of regenerants differed from the starting plant after two rounds on a cytokinin medium, against 0 of 8 without it.⁴⁵ In other aroids, tissue-cultured populations have thrown new forms: about 22 Syngonium cultivars were selected from large cultured populations tracing to ‘White Butterfly’.^46,47,48

Of the lab protocols for four variegated aroid cultivars, ‘Thai Constellation’ among them, three did not score the regenerants’ variegation.^52,51 On ‘White Knight’, regenerated from leaf-stalk pieces, most shoots had plain green leaves and only a subset was variegated, without a count.⁵²

On ‘Thai Constellation’, single keepers report an occasional half-moon leaf, a few in a couple of decades, and on one old plant a half-white side shoot, one plant’s identity unverified.^53,2,54

What is said about ‘Albo’ comes from retailer, blog and forum statements, without counts.^49,50 On trade ‘Albo’, reversion is described per growing point: a shoot tip that switches to all-green leaves is described as staying green, and less often a tip switches to all-white leaves.^54,55,49 Half-moon leaves and growing points turning all green or all white are described on it; a white cell line in the growing tip would give this picture whatever its cause, nuclear or plastid.^49,55

All-green leaves on ‘Albo’ are blamed on too little light, on too much direct sun, or on neither; of two white-variegated plants of unnamed cultivar, one made an all-green leaf at a window without direct sun, the other whiter leaves at a very bright window, with the light not read at either.^56,57,54

All-white ‘Albo’ leaves and cuttings are described as browning or dying and as unable to root on their own, and in non-aroid variegated plants, chlorophyll-free shoots likewise failed once they had to stand alone, while in petunia a white sector grew and flowered as long as it stayed attached.^2,3,4

‘Albo’ is propagated by nodal cuttings, air layering and cutting back to a node; a node showing only green tissue is described as giving a green plant, and whether ‘Albo’ is tissue-cultured at all is disputed.^2,57,50 For a reverted ‘Albo’ shoot, cutting back to a node with white in its stem is the remedy described; its outcome is put as odds, not a guarantee, and cutting off green shoots is also called useless.^54,56

One conservatory plant that had climbed about 12 m flowered and fruited regularly, and M. deliciosa is also reported to flower readily once it has reached a certain size.^2,1 One fruit-crop account states, without giving a basis, that potted plants kept indoors, conservatories and greenhouses included, do not bloom or fruit in confinement.³ Both the flowering reports and this statement come without measured conditions.^2,3

Since the stigmas stop before the same flower spike sheds pollen, selfing within one flower spike is described as impossible, yet in wild Monstera lentii some bagged flower spikes still set fruit.^4,5 In wild Monstera lentii, 6 of 11 flower spikes closed to all visitors still set fruit, at about 10 % fruit set against 61.4 % under natural pollination.⁵

Grown outdoors as a fruit crop, plants from cuttings are said to begin bearing after 4–6 years, and a fruit takes 12–14 months from flowering to ripeness.^6,3 Ripe fruit is described as edible only where the rind scales have loosened enough to flick off, and it ripens toward its tip over 5 or 6 days at room temperature.³ Some people report throat irritation even from ripe fruit, and hives and worse are reported after eating it, so eating it in quantity before one’s reaction is known is advised against.³ In Monstera, except M. obliqua, the ripe fruit sheds its cap of needle-bearing cells in large segments or all at once, exposing the seeds in the pulp.⁷

Among recorded hobby crosses, mostly in Anthurium and Philodendron, whether a plant flowers in cultivation limited crosses more than compatibility did.¹

M. deliciosa is listed among the arum family’s oxalate plants poisonous to dogs, cats and small pets, with mouth and skin irritation, swelling, drooling, vomiting, difficulty swallowing and possible throat swelling named as signs for the family.¹ For an animal exposed to an oxalate plant, the first aid given is rinsing or wiping the affected area with cold water and close watching of the airway.¹ For plant poisoning in pets in general, the step given is a visit to the vet, with the rest of the plant or a photo of it when the plant cannot be named.¹

For M. deliciosa, all parts of the plant, the unripe fruit and the flower remnants on the ripe fruit are described as irritating mouth and skin, in accounts without cases or doses.^3,4 Its crystals are also said to irritate the gut lining and the eye.^3,4 Across the genus Monstera, these crystals are most abundant in the fruit and seed coat.² For M. deliciosa itself, one work with one plant per light condition lists raphides in the midrib and leaf stalk in one place, and in another reports none in light and shade plants except a few needles in the leaf stalk.² Of 166 cats treated at one emergency clinic for confirmed or suspected poisoning, two came after assumed M. deliciosa exposure, and both survived to discharge.⁵ In farm animals, M. deliciosa is cited as causing only light changes of the mouth lining.⁶

For Rhaphidophora tetrasperma, the midrib’s width and colour rest on a single description.^2,3 ‘Monstera minima’ is printed as a further name of Rhaphidophora tetrasperma.⁵

On an adult plant, M. deliciosa has no waxy bloom on stem or leaf stalks and holes of very unequal sizes, while M. tacanaensis has a bloom and few holes of similar size; a shaded or dry M. deliciosa also makes few holes, so the hole test alone can mislead.^2,6 A young M. deliciosa resembles an adult M. tacanaensis, so these adult checks do not settle a young pot plant.² The length of the joint under the blade is no reliable check between the two species, since the printed ranges disagree.^2,4,7

On adult leaves and without flowers, a swollen joint directly under the blade points to Monstera, while Philodendron lacks it in all but very rare cases.⁸ A ‘pothos’ label names no genus: nursery plants sold as pothos in one country belonged to Epipremnum, Philodendron, Scindapsus, Rhaphidophora and Monstera, and none to Pothos.⁹ In a tree built from whole chloroplast genomes, M. deliciosa grouped most closely with M. adansonii among the species in that tree.¹⁰